# Meson Particle Listings

## f₂(1270)

<table><tbody><tr><td>1275</td><td>±10</td><td>AKER</td><td>91</td><td>CBAR</td><td>0.0 p̄p → 3π<sup>0</sup></td></tr><tr><td>1220</td><td>±10</td><td>BREAKSTONE</td><td>90</td><td>SFM</td><td>p̄p → p̄pπ<sup>+π<sup>-</sup></sup></td></tr><tr><td>1288</td><td>±12</td><td>ABACHI</td><td>86B</td><td>HRS</td><td>e<sup>+</sup>e<sup>-</sup> → π<sup>+</sup>π<sup>-</sup>X</td></tr><tr><td>1284</td><td>±30</td><td>BINON</td><td>83</td><td>GAM2</td><td>38 π<sup>-</sup> p → n2η</td></tr><tr><td>1280</td><td>±20</td><td>APEL</td><td>82</td><td>CNTR</td><td>25 π<sup>-</sup> p → n2π<sup>0</sup></td></tr><tr><td>1284</td><td>±10</td><td>16000</td><td></td><td>DEUTSCH...</td><td>76 HBC 16 π<sup>+</sup> p</td></tr><tr><td>1258</td><td>±10</td><td>600</td><td></td><td>TAKAHASHI</td><td>72 HBC 8 π<sup>-</sup> p → n2π</td></tr><tr><td>1275</td><td>±13</td><td></td><td></td><td>ARMENISE</td><td>70 HBC 9 π<sup>+</sup> n → p<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1261</td><td>±5</td><td>1960</td><td></td><td>ARMENISE</td><td>68 DBC 5.1 π<sup>+</sup> n → p<sup>+</sup>MM<sup>-</sup></td></tr><tr><td>1270</td><td>±10</td><td>360</td><td></td><td>ARMENISE</td><td>68 DBC 5.1 π<sup>+</sup> n → p<sup>+</sup>MM</td></tr><tr><td>1268</td><td>±6</td><td>13 JOHNSON</td><td>68</td><td>HBC</td><td>3.7-4.2 π<sup>-</sup> p</td></tr></tbody></table>

¹ Averaged over six nuclear targets, no statistically significant dependence on target nucleus observed.

² Breit-Wigner mass.

³ Mass errors enlarged by us to $Γ/\sqrt{N}$; see the note with the $K^*(892)$ mass.

⁴ From a partial-wave analysis of data using a K-matrix formalism with 5 poles.

⁵ From an energy-independent partial-wave analysis.

⁶ From an amplitude analysis of the reaction $π^+π^- → 2π^0$.

⁷ From an amplitude analysis of $π^+π^- → π^+π^-$ scattering data.

⁸ Fit of the tensor partial waves from BES3 in the multipole basis.

⁹ Using CLEO-c data but not authored by the CLEO Collaboration.

¹⁰ From a fit to a Breit-Wigner line shape with fixed $Γ = 185$ MeV.

¹¹ From analysis of L3 data at 91 and 183–209 GeV.

¹² Systematic uncertainties not estimated.

¹³ JOHNSON 68 includes BONDAR 63, LEE 64, DERADO 65, EISNER 67.

## f₂(1270) WIDTH

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>186.6<sup>+2.8</sup><sub>-2.2</sub> OUR FIT</strong> Error includes scale factor of 1.5.</td></tr><tr><td colspan="5"><strong>185.8<sup>+2.8</sup><sub>-2.1</sub> OUR AVERAGE</strong> Error includes scale factor of 1.6. See the ideogram below.</td></tr><tr><td>190.3 ± 1.9 ± 1.8</td><td></td><td>1 BOGOLYUB...</td><td>13</td><td>SPEC 7π<sup>+</sup>(K<sup>+</sup>,p)A → nγ + X</td></tr><tr><td>175 <sup>+6</sup><sub>-4</sub> ±10</td><td></td><td>2 ABLIKIM</td><td>06V</td><td>BES2 e<sup>+</sup>e<sup>-</sup> → J/ψ → γπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>190 ±20</td><td></td><td>ABLIKIM</td><td>05</td><td>BES2 J/ψ → φπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>171 ±10</td><td></td><td>ALDE</td><td>98</td><td>GAM4 100 π<sup>-</sup> p → π<sup>0</sup>π<sup>0</sup> n</td></tr><tr><td>192 ±5</td><td>200k</td><td>PROKOSHKIN</td><td>94</td><td>GAM2 38 π<sup>-</sup> p → π<sup>0</sup>π<sup>0</sup> n</td></tr><tr><td>180 ±24</td><td></td><td>AGUILAR-...</td><td>91</td><td>EHS 400 p̄p</td></tr><tr><td>169 ±9</td><td>5730</td><td>3 AUGUSTIN</td><td>89</td><td>D2M e<sup>+</sup>e<sup>-</sup> → 5π</td></tr><tr><td>150 ±30</td><td>400</td><td>3 ALDE</td><td>87</td><td>GAM4 100 π<sup>-</sup> p → 4π<sup>0</sup> n</td></tr><tr><td>186 <sup>+9</sup><sub>-2</sub></td><td></td><td>4 LONGACRE</td><td>86</td><td>MPS 22 π<sup>-</sup> p → n2K<sup>0</sup><sub>S</sub></td></tr><tr><td>179.2<sup>+6.9</sup><sub>-6.6</sub></td><td></td><td>5 CHABAUD</td><td>83</td><td>ASPK 17 π<sup>-</sup> p polarized</td></tr><tr><td>160 ±11</td><td></td><td>DENNEY</td><td>83</td><td>LASS 10 π<sup>+</sup> N</td></tr><tr><td>196 ±10</td><td>3k</td><td>APEL</td><td>82</td><td>CNTR 25 π<sup>-</sup> p → n2π<sup>0</sup></td></tr><tr><td>152 ±9</td><td></td><td>6 CASON</td><td>82</td><td>STRC 8 π<sup>+</sup> p → Δ<sup>+</sup>π<sup>0</sup>π<sup>0</sup></td></tr><tr><td>186 ±27</td><td>11600</td><td>GIDAL</td><td>81</td><td>MRK2 J/ψ decay</td></tr><tr><td>216 ±13</td><td></td><td>7 CORDEN</td><td>79</td><td>OMEG 12–15 π<sup>-</sup> p → n2π</td></tr><tr><td>190 ±10</td><td>10k</td><td>APEL</td><td>75</td><td>NICE 40 π<sup>-</sup> p → n2π<sup>0</sup></td></tr><tr><td>192 ±16</td><td>4600</td><td>ENGLER</td><td>74</td><td>DBC 6 π<sup>+</sup> n → π<sup>+</sup>π<sup>-</sup> p</td></tr><tr><td>183 ±15</td><td>5300</td><td>FLATTE</td><td>71</td><td>HBC 7 π<sup>+</sup> p → Δ<sup>+</sup> f<sub>2</sub></td></tr><tr><td>196 ±30</td><td></td><td>3 STUNTEBECK</td><td>70</td><td>HBC 8 π<sup>-</sup> p, 5.4 π<sup>+</sup> d</td></tr><tr><td>216 ±20</td><td>1960</td><td>3 ARMENISE</td><td>68</td><td>DBC 5.1 π<sup>+</sup> n → p<sup>+</sup>MM<sup>-</sup></td></tr><tr><td>128 ±27</td><td></td><td>3 BOESEBECK</td><td>68</td><td>HBC 8 π<sup>+</sup> p</td></tr><tr><td>176 ±21</td><td></td><td>3,8 JOHNSON</td><td>68</td><td>HBC 3.7–4.2 π<sup>-</sup> p</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>168 ± 7</td><td>9 KLEMPT</td><td>22</td><td>RVUE J/ψ(1S) → γπ<sup>0</sup>π<sup>0</sup>, γK<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub></td></tr><tr><td>183 ± 2</td><td>CARVER</td><td>21</td><td>CLAS γp → π<sup>0</sup>π<sup>0</sup> p</td></tr><tr><td>195 ±15</td><td>870</td><td>10 SCHEGELSKY</td><td>06A RVUE γγ → K<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub></td></tr><tr><td>121 ±26</td><td></td><td>TIKHOMIROV</td><td>03 SPEC 40.0 π<sup>-</sup> C → K<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>L</sub>X</td></tr><tr><td>187 ±20</td><td></td><td>11 ALDE</td><td>97</td><td>GAM2 450 p̄p → p̄pπ<sup>0</sup>π<sup>0</sup>π<sup>0</sup></td></tr><tr><td>184 ±10</td><td></td><td>11 GRYGOREV</td><td>96</td><td>SPEC 40 π<sup>-</sup> N → K<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub>X</td></tr><tr><td>200 ±10</td><td></td><td>AKER</td><td>91</td><td>CBAR 0.0 p̄p → 3π<sup>0</sup></td></tr><tr><td>240 ±40</td><td>3k</td><td>BINON</td><td>83</td><td>GAM2 38 π<sup>-</sup> p → n2η</td></tr><tr><td>187 ±30</td><td>650</td><td>3 ANTIPOV</td><td>77</td><td>CIBS 25 π<sup>-</sup> p → p3π</td></tr><tr><td>225 ±38</td><td>16000</td><td>DEUTSCH...</td><td>76</td><td>HBC 16 π<sup>+</sup> p</td></tr><tr><td>166 ±28</td><td>600</td><td>3 TAKAHASHI</td><td>72</td><td>HBC 8 π<sup>-</sup> p → n2π</td></tr><tr><td>173 ±53</td><td></td><td>3 ARMENISE</td><td>70</td><td>HBC 9 π<sup>+</sup> n → p<sup>+</sup>π<sup>-</sup></td></tr></tbody></table>

¹ Averaged over six nuclear targets, no statistically significant dependence on target nucleus observed.

² Breit-Wigner width

³ Width errors enlarged by us to $4Γ/\sqrt{N}$; see the note with the $K^*(892)$ mass.

⁴ From a partial-wave analysis of data using a K-matrix formalism with 5 poles.

⁵ From an energy-independent partial-wave analysis.

⁶ From an amplitude analysis of the reaction $π^+π^- → 2π^0$.

⁷ From an amplitude analysis of $π^+π^- → π^+π^-$ scattering data.

⁸ JOHNSON 68 includes BONDAR 63, LEE 64, DERADO 65, EISNER 67.

⁹ Fit of the tensor partial waves from BES3 in the multipole basis.

¹⁰ From analysis of L3 data at 91 and 183–209 GeV.

¹¹ Systematic uncertainties not estimated.

## WEIGHTED AVERAGE
185.8+2.8-2.1 (Error scaled by 1.6)

<figure><img src="image_452.png" /></figure>

Values above of weighted average, error, and scale factor are based upon the data in this ideogram only. They are not necessarily the same as our 'best' values. Obtained from a least-squares constrained fit utilizing measurements of other (related) quantities as additional information.

<caption>f₂(1270) width (MeV)</caption>

## f₂(1270) DECAY MODES

<table><thead><tr><th>Mode</th><th>Fraction (Γ<sub>f</sub>/Γ)</th><th>Scale factor/<br>Confidence level</th></tr></thead><tbody><tr><td>Γ<sub>1</sub> ππ</td><td>(84.3 <sup>+2.8</sup><sub>-1.0</sub>)%</td><td>S=1.2</td></tr><tr><td>Γ<sub>2</sub> π<sup>+</sup>π<sup>-</sup> 2π<sup>0</sup></td><td>(7.7 <sup>+1.2</sup><sub>-3.1</sub>)%</td><td>S=1.2</td></tr><tr><td>Γ<sub>3</sub> K<span style="text-decoration: overline">K</span></td><td>(4.6 <sup>+0.4</sup><sub>-0.1</sub>)%</td><td>S=2.7</td></tr><tr><td>Γ<sub>4</sub> 2π<sup>+</sup> 2π<sup>-</sup></td><td>(2.8 <sup>+0.4</sup><sub>-0.1</sub>)%</td><td>S=1.2</td></tr><tr><td>Γ<sub>5</sub> ηη</td><td>(4.0 <sup>+0.8</sup><sub>-0.3</sub>) × 10<sup>-3</sup></td><td>S=2.1</td></tr><tr><td>Γ<sub>6</sub> 4π<sup>0</sup></td><td>(3.0 <sup>+1.0</sup><sub>-0.3</sub>) × 10<sup>-3</sup></td><td></td></tr><tr><td>Γ<sub>7</sub> γγ</td><td>(1.42 ± 0.24) × 10<sup>-5</sup></td><td>S=1.4</td></tr><tr><td>Γ<sub>8</sub> ηππ</td><td>&lt; 8</td><td>CL=95%</td></tr><tr><td>Γ<sub>9</sub> K<sup>0</sup> K<sup>-</sup> π<sup>+</sup> + c.c.</td><td>&lt; 3.4</td><td>CL=95%</td></tr><tr><td>Γ<sub>10</sub> e<sup>+</sup>e<sup>-</sup></td><td>&lt; 6</td><td>CL=90%</td></tr></tbody></table>

## CONSTRAINED FIT INFORMATION

An overall fit to the total width, 4 partial widths, a combination of partial widths obtained from integrated cross sections, and 6 branching ratios uses 44 measurements and one constraint to determine 8 parameters. The overall fit has a $χ^2 = 82.3$ for 37 degrees of freedom.

The following off-diagonal array elements are the correlation coefficients $\langle\delta\rho_i\delta\rho_j\rangle/(\delta\rho_i\cdot\delta\rho_j)$, in percent, from the fit to parameters $\rho_i$, including the branching fractions, $x_i \equiv \Gamma_i/\Gamma_{\text{total}}$. The fit constrains the $x_i$ whose labels appear in this array to sum to one.

<figure><img src="image_453.png" /></figure>

<table><thead><tr><th>Mode</th><th>Rate (MeV)</th><th>Scale factor</th></tr></thead><tbody><tr><td>Γ<sub>1</sub> ππ</td><td>157.2</td><td>+5.0<br>-1.0</td></tr><tr><td>Γ<sub>2</sub> π<sup>+</sup>π<sup>-</sup> 2π<sup>0</sup></td><td>14.3</td><td>+2.3<br>-6.0</td></tr><tr><td>Γ<sub>3</sub> K<span style="text-decoration: overline">K</span></td><td>8.5</td><td>±0.8</td></tr><tr><td>Γ<sub>4</sub> 2π<sup>+</sup> 2π<sup>-</sup></td><td>5.2</td><td>±0.7</td></tr></tbody></table>
<table><tr><td>Γ<sub>5</sub></td><td>ηη</td><td>0.75 ± 0.14</td><td>2.1</td></tr><tr><td>Γ<sub>6</sub></td><td>4π<sup>0</sup></td><td>0.56 ± 0.19</td><td></td></tr><tr><td>Γ<sub>7</sub></td><td>γγ</td><td>0.0026 ± 0.0005</td><td>1.4</td></tr></table>

$f_2(1270)$ PARTIAL WIDTHS

<table><thead><tr><th>Γ(ππ)</th><th>Γ<sub>1</sub></th></tr><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

157.2<sup>+5.0</sup><sub>-1.0</sub> OUR FIT

157.0<sup>+6.0</sup><sub>-1.0</sub> 1 LONGACRE 86 MPS 22π⁻p → n2K⁰S

• • • We do not use the following data for averages, fits, limits, etc. • • •

152 ± 8 870 2 SCHEGELSKY 06A RVUE γγ → K⁰S K⁰S

¹From a partial-wave analysis of data using a K-matrix formalism with 5 poles.

²From analysis of L3 data at 91 and 183–209 GeV and using SU(3) relations.

<table><thead><tr><th>Γ(KK̄)</th><th>Γ<sub>3</sub></th></tr><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

8.5±0.8 OUR FIT Error includes scale factor of 2.8.

9.0<sup>+0.7</sup><sub>-0.3</sub> 1 LONGACRE 86 MPS 22π⁻p → n2K⁰S

• • • We do not use the following data for averages, fits, limits, etc. • • •

7.5±2.0 870 2 SCHEGELSKY 06A RVUE γγ → K⁰S K⁰S

¹From a partial-wave analysis of data using a K-matrix formalism with 5 poles.

²From analysis of L3 data at 91 and 183–209 GeV and using SU(3) relations.

<table><thead><tr><th>Γ(ηη)</th><th>Γ<sub>5</sub></th></tr><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

0.75±0.14 OUR FIT Error includes scale factor of 2.1.

1.0 ±0.1 1 LONGACRE 86 MPS 22π⁻p → n2K⁰S

• • • We do not use the following data for averages, fits, limits, etc. • • •

1.8 ± 0.4 870 2 SCHEGELSKY 06A RVUE γγ → K⁰S K⁰S

¹From a partial-wave analysis of data using a K-matrix formalism with 5 poles.

²From analysis of L3 data at 91 and 183–209 GeV and using SU(3) relations.

<table><thead><tr><th>Γ(γγ)</th><th>Γ<sub>7</sub></th></tr><tr><th>VALUE (keV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

2.6 ± 0.5 OUR FIT Error includes scale factor of 1.4.

<table><tr><td>2.93±0.40</td><td>1 DAI</td><td>14A</td><td>RVUE</td><td>Compilation</td></tr><tr><td>3.14±0.20</td><td>2,3 PENNINGTON 08</td><td>RVUE</td><td>Compilation</td><td></td></tr><tr><td>3.82±0.30</td><td>3,4 PENNINGTON 08</td><td>RVUE</td><td>Compilation</td><td></td></tr><tr><td>2.55±0.15</td><td>5 SCHEGELSKY 06A</td><td>RVUE</td><td>γγ → K⁰S K⁰S</td><td></td></tr><tr><td>2.84±0.35</td><td>BOGLIONE</td><td>99</td><td>RVUE</td><td>γγ → π⁺π⁻, π⁰π⁰</td></tr><tr><td>2.93±0.23±0.32</td><td>6 YABUKI</td><td>95</td><td>VNS</td><td></td></tr><tr><td>2.58±0.13<sup>+0.36</sup><sub>-0.27</sub></td><td>7 BEHREND</td><td>92</td><td>CELL</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>3.10±0.35±0.35</td><td>8 BLINOV</td><td>92</td><td>MD1</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>2.27±0.47±0.11</td><td>ADACHI</td><td>90D</td><td>TOPZ</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>3.15±0.04±0.39</td><td>BOYER</td><td>90</td><td>MRK2</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>3.19±0.16<sup>+0.29</sup><sub>-0.28</sub></td><td>MARSISKE</td><td>90</td><td>CBAL</td><td>e⁺e⁻ → e⁺e⁻π⁰π⁰</td></tr><tr><td>2.35±0.65</td><td>9 MORGAN</td><td>90</td><td>RVUE</td><td>γγ → π⁺π⁻, π⁰π⁰</td></tr><tr><td>3.19±0.09<sup>+0.22</sup><sub>-0.38</sub></td><td>2177 OEST</td><td>90</td><td>JADE</td><td>e⁺e⁻ → e⁺e⁻π⁰π⁰</td></tr><tr><td>3.2 ± 0.1 ± 0.4</td><td>10 AIHARA</td><td>86B</td><td>TPC</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>2.5 ± 0.1 ± 0.5</td><td>BEHREND</td><td>84B</td><td>CELL</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>2.85±0.25±0.5</td><td>11 BERGER</td><td>84</td><td>PLUT</td><td>e⁺e⁻ → e⁺e⁻2π</td></tr><tr><td>2.70±0.05±0.20</td><td>COURAU</td><td>84</td><td>DLCO</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>2.52±0.13±0.38</td><td>12 SMITH</td><td>84</td><td>MRK2</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>2.7 ± 0.2 ± 0.6</td><td>EDWARDS</td><td>82F</td><td>CBAL</td><td>e⁺e⁻ → e⁺e⁻2π⁰</td></tr><tr><td>2.9 <sup>+0.6</sup><sub>-0.4</sub> ± 0.6</td><td>13 EDWARDS</td><td>82F</td><td>CBAL</td><td>e⁺e⁻ → e⁺e⁻2π⁰</td></tr><tr><td>3.2 ± 0.2 ± 0.6</td><td>BRANDELIK</td><td>81B</td><td>TASS</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>3.6 ± 0.3 ± 0.5</td><td>ROUSSARIE</td><td>81</td><td>MRK2</td><td>e⁺e⁻ → e⁺e⁻π⁺π⁻</td></tr><tr><td>2.3 ± 0.8</td><td>14 BERGER</td><td>80B</td><td>PLUT</td><td>e⁺e⁻</td></tr></table>

¹Based on a K-matrix analysis of BELLE data from MORI 07, UEHARA 08A, UEHARA 09 and UEHARA 13. The width is derived for the pole on the third sheet which is closest to the physical axis. Supersedes PENNINGTON 08.

²Solution A (preferred solution based on χ²-analysis).

³Dispersion theory based amplitude analysis of BOYER 90, MARSISKE 90, BEHREND 92, and MORI 07.

⁴Solution B (worse than solution A; still acceptable when systematic uncertainties are included).

⁵From analysis of L3 data at 91 and 183–209 GeV and using SU(3) relations.

⁶With a narrow scalar state around 1220 MeV.

⁷Using a unitarized model with a 300–500 keV wide scalar at 1100 MeV.

⁸Using the unitarized model of LYTH 85.

⁹Error includes spread of different solutions. Data of MARK2 and CRYSTAL BALL used in the analysis. Authors report strong correlations with γγ width of $f_0(1370) : Γ(f_2) + 1/4 Γ(f^0) = 3.6 \pm 0.3$ KeV.

¹⁰Radiative corrections modify the partial widths; for instance the COURAU 84 value becomes 2.66 ± 0.21 in the calculation of LANDRO 86.

¹¹Using the MENNESSIER 83 model.

¹²Superseded by BOYER 90.

¹³If helicity = 2 assumption is not made.

¹⁴Using mass, width and B($f_2(1270) \rightarrow 2\pi$) from PDG 78.

<table><thead><tr><th>Γ(e⁺e⁻)</th><th>Γ<sub>10</sub></th></tr><tr><th>VALUE (eV)</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>&lt;0.11</td><td>90</td><td>ACHASOV</td><td>00K</td><td>SND</td><td>e⁺e⁻ → π⁰π⁰</td></tr><tr><td>• • • We do not use the following data for averages, fits, limits, etc. • • •</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>&lt;1.7</td><td>90</td><td>VOROBYEV</td><td>88</td><td>ND</td><td>e⁺e⁻ → π⁰π⁰</td></tr></tbody></table>

$f_2(1270)$ Γ(i)Γ(γγ)/Γ(total)

<table><thead><tr><th>Γ(KK̄) × Γ(γγ)/Γ<sub>total</sub></th><th>Γ<sub>3</sub>Γ<sub>7</sub>/Γ</th></tr><tr><th>VALUE (keV)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

0.121±0.020 OUR FIT Error includes scale factor of 1.3.

0.091±0.007±0.027 1 ALBRECHT 90G ARG e⁺e⁻ → e⁺e⁻K⁺K⁻

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.104±0.007±0.072 2 ALBRECHT 90G ARG e⁺e⁻ → e⁺e⁻K⁺K⁻

¹Using an incoherent background.

²Using a coherent background.

<table><thead><tr><th>Γ(ηη) × Γ(γγ)/Γ<sub>total</sub></th><th>Γ<sub>5</sub>Γ<sub>7</sub>/Γ</th></tr><tr><th>VALUE (eV)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>11.5<sup>+1.8</sup><sub>-2.0</sub>±4.5</td><td>1 UEHARA</td><td>10A</td><td>BELL</td><td>10.6 e⁺e⁻ → e⁺e⁻ηη</td></tr></tbody></table>

¹Including interference with the $f'_2(1525)$ (parameters fixed to the values from the 2008 edition of this review, PDG 08) and $f_0(\gamma)$.

<table><thead><tr><th>Helicity-0/Helicity-2 RATIO IN γγ → f<sub>2</sub>(1270) → ππ</th><th>Γ<sub>1</sub>/Γ</th></tr><tr><th>VALUE (units 10<sup>-2</sup>)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

3.7±0.3<sup>+15.9</sup><sub>-2.9</sub> UEHARA 08A BELL 10.6 e⁺e⁻ → e⁺e⁻π⁰π⁰

• • • We do not use the following data for averages, fits, limits, etc. • • •

9.5±1.8 1 DAI 14A RVUE Compilation

13 2,3 PENNINGTON 08 RVUE Compilation

26 3,4 PENNINGTON 08 RVUE Compilation

¹Based on a K-matrix analysis of BELLE data from MORI 07, UEHARA 08A, UEHARA 09 and UEHARA 13. The width is derived for the pole on the third sheet which is closest to the physical axis.

²Solution A (preferred solution based on χ²-analysis).

³Dispersion theory based amplitude analysis of BOYER 90, MARSISKE 90, BEHREND 92, and MORI 07.

⁴Solution B (worse than solution A; still acceptable when systematic uncertainties are included).

$f_2(1270)$ BRANCHING RATIOS

<table><thead><tr><th>Γ(ππ)/Γ<sub>total</sub></th><th>Γ<sub>1</sub>/Γ</th></tr><tr><th>VALUE</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

0.843<sup>+0.028</sup><sub>-0.010</sub> OUR FIT Error includes scale factor of 1.2.

<table><thead><tr><th>0.837±0.020 OUR AVERAGE</th><th>CHABAUD</th><th>83</th><th>ASPK</th><th>17π⁻p polarized</th></tr></thead><tbody><tr><td>0.849±0.025</td><td>CHABAUD</td><td>83</th><td>ASPK</td><td>17π⁻p polarized</td></tr><tr><td>0.85 ± 0.05</td><td>BEAUPRE</td><td>71</td><td>HBC</td><td>8π⁺p → Δ⁺⁺f<sub>2</sub></td></tr><tr><td>0.8 ± 0.04</td><td>OH</td><td>70</td><td>HBC</td><td>1.26π⁻p → π⁺π⁻n</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.856±0.001±0.05 1 ALBRECHT 20 RVUE 0.9 p → π⁰π⁰η, π⁰ηη, π⁰K⁺K⁻

¹Residue from T-matrix pole, 4 poles, 4 channels, including scattering data from HYAMS 75 (ππ), LONGACRE 86 (K̄K̄), BINON 83 (ηη).

<table><thead><tr><th>Γ(π⁺π⁻2π⁰)/Γ(ππ)</th><th>Γ<sub>2</sub>/Γ<sub>1</sub></th></tr><tr><th>VALUE</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

0.091<sup>+0.015</sup><sub>-0.040</sub> OUR FIT Error includes scale factor of 1.2.

0.15 ± 0.06 600 EISENBERG 74 HBC 4.9 π⁺p → Δ⁺⁺f<sub>2</sub>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.07 EMMS 75D DBC 4 π⁺n → p f<sub>2</sub>

<table><thead><tr><th>Γ(KK̄)/Γ<sub>total</sub></th><th>Γ<sub>3</sub>/Γ</th></tr><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.033±0.001±0.005 1 ALBRECHT 20 RVUE 0.9 p → π⁰π⁰η, π⁰ηη, π⁰K⁺K⁻

¹Residue from T-matrix pole, 4 poles, 4 channels, including scattering data from HYAMS 75 (ππ), LONGACRE 86 (K̄K̄), BINON 83 (ηη).
$\Gamma(K\bar{K})/\Gamma(\pi\pi)$

$\Gamma_3/\Gamma_1$

We average only experiments which either take into account $f_2(1270)-\alpha_2(1320)$ interference explicitly or demonstrate that $\alpha_2(1320)$ production is negligible.

<table><thead><tr><th>VALUE</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

$0.054 \pm 0.005$

0.006 OUR FIT

Error includes scale factor of 2.7.

$0.041 \pm 0.004$

<table><thead><tr><th>0.045 ± 0.01</th><th>1</th><th>BARGIOTTI</th><th>03</th><th>OBLX</th><th>πp</th></tr></thead><tbody><tr><td>0.037<sup>+0.008</sup><sub>-0.021</sub></td><td></td><td>ETKIN</td><td>82b</td><td>MPS</td><td>23 π<sup>-</sup> p → n2K<sup>0</sup><sub>S</sub></td></tr><tr><td>0.045 ± 0.009</td><td></td><td>CHABAUD</td><td>81</td><td>ASPK</td><td>17 π<sup>-</sup> p polarized</td></tr><tr><td>0.039 ± 0.008</td><td></td><td>LOVERRE</td><td>80</td><td>HBC</td><td>4 π<sup>-</sup> p → K<sup>-</sup>π<sup>-</sup> N</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>0.052 ± 0.025</td><td>ABLIKIM</td><td>04e</td><td>BES2</td><td>J/ψ → ωK<sup>+</sup> K<sup>-</sup></td></tr><tr><td>0.036 ± 0.025</td><td>2</td><td>COSTA</td><td>80</td><td>OMEG</td><td>1-2.2 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> n</td></tr><tr><td>0.030 ± 0.005</td><td>3</td><td>MARTIN</td><td>79</td><td>RVUE</td><td></td></tr><tr><td>0.027 ± 0.009</td><td>4</td><td>POLYCHRO...</td><td>79</td><td>STRC</td><td>7 π<sup>-</sup> p → n2K<sup>0</sup><sub>S</sub></td></tr><tr><td>0.025 ± 0.015</td><td>EMMS</td><td>75d</td><td>DBC</td><td>4 π<sup>+</sup> n → p f<sub>2</sub></td></tr><tr><td>0.031 ± 0.012</td><td>20</td><td>ADERHOLZ</td><td>69</td><td>HBC</td><td>8 π<sup>+</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>+</sup> n</td></tr></tbody></table>

1 Coupled channel analysis of $\pi^+\pi^-\pi^0$, $K^+K^-\pi^0$, and $K^\pm K^0\pi^\mp$.

2 Re-evaluated by CHABAUD 83.

3 Includes PAWLICKI 77 data.

4 Takes into account the $f_2(1270)-f_2'(1525)$ interference.

$\Gamma(2\pi^+ 2\pi^-)/\Gamma(\pi\pi)$

$\Gamma_4/\Gamma_1$

<table><thead><tr><th>VALUE</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.033 ± 0.005</td><td>OUR FIT</td><td colspan="3">Error includes scale factor of 1.2.</td></tr><tr><td>0.033 ± 0.004</td><td>OUR AVERAGE</td><td colspan="3">Error includes scale factor of 1.1.</td></tr><tr><td>0.024 ± 0.006</td><td>160</td><td>EMMS</td><td>75d</td><td>DBC</td><td>4 π<sup>+</sup> n → p f<sub>2</sub></td></tr><tr><td>0.051 ± 0.025</td><td>70</td><td>EISENBERG</td><td>74</td><td>HBC</td><td>4.9 π<sup>+</sup> p → Δ<sup>++</sup> f<sub>2</sub></td></tr><tr><td>0.043<sup>+0.007</sup><sub>-0.011</sub></td><td>285</td><td>1 LOUIE</td><td>74</td><td>HBC</td><td>3.9 π<sup>-</sup> p → n f<sub>2</sub></td></tr><tr><td>0.037 ± 0.007</td><td>154</td><td>ANDERSON</td><td>73</td><td>DBC</td><td>6 π<sup>+</sup> n → p f<sub>2</sub></td></tr><tr><td>0.047 ± 0.013</td><td></td><td>OH</td><td>70</td><td>HBC</td><td>1.26 π<sup>-</sup> p → π<sup>+</sup> π<sup>-</sup> n</td></tr></tbody></table>

1 LOUIE 74 was quoted as 0.065 in PDG 74. Factor 2/3 to go from $\pi^+\pi^- \to \pi\pi$ forgotten. Mike L.

$\Gamma(\eta\eta)/\Gamma(\pi\pi)$

$\Gamma_5/\Gamma$

<table><thead><tr><th>VALUE (units 10<sup>-3</sup>)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>4.0 ± 0.8</td><td>OUR FIT</td><td colspan="2">Error includes scale factor of 2.1.</td></tr><tr><td>2.9 ± 0.5</td><td>OUR AVERAGE</td><td colspan="2"></td></tr><tr><td>2.7 ± 0.7</td><td>BINON</td><td>05</td><td>GAMS</td><td>33 π<sup>-</sup> p → ηηη</td></tr><tr><td>2.8 ± 0.7</td><td>ALDE</td><td>86d</td><td>GAM4</td><td>100 π<sup>-</sup> p → 2ηη</td></tr><tr><td>5.2 ± 1.7</td><td>BINON</td><td>83</td><td>GAM2</td><td>38 π<sup>-</sup> p → 2ηη</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>4.0 ± 1.0 ± 2.0</td><td>1</td><td>ALBRECHT</td><td>20</td><td>RVUE</td><td>0.9 πp → π<sup>0</sup> π<sup>0</sup> η<sub>1</sub>, π<sup>0</sup> π<sup>0</sup> K<sup>+</sup> K<sup>-</sup></td></tr></tbody></table>

1 Residue from T-matrix pole, 4 poles, 4 channels, including scattering data from HYAMS 75 ($\pi\pi$), LONGACRE 86 ($K\bar{K}$), BINON 83 ($\eta\eta$).

$\Gamma(\eta\eta)/\Gamma(\pi\pi)$

$\Gamma_5/\Gamma_1$

<table><thead><tr><th>VALUE</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.003 ± 0.001</td><td></td><td>BARBERIS</td><td>00e</td><td>450 pp → p f<sub>ηη</sub> p<sub>S</sub></td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>&lt;0.05</td><td>95</td><td>EDWARDS</td><td>82f</td><td>CBAL</td><td>e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> 2η</td></tr><tr><td>&lt;0.016</td><td>95</td><td>EMMS</td><td>75d</td><td>DBC</td><td>4 π<sup>+</sup> n → p f<sub>2</sub></td></tr><tr><td>&lt;0.09</td><td>95</td><td>EISENBERG</td><td>74</td><td>HBC</td><td>4.9 π<sup>+</sup> p → Δ<sup>++</sup> f<sub>2</sub></td></tr></tbody></table>

$\Gamma(4\pi^0)/\Gamma(\pi\pi)$

$\Gamma_6/\Gamma$

<table><thead><tr><th>VALUE</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.0030 ± 0.0010</td><td>OUR FIT</td><td></td><td></td><td></td></tr><tr><td>0.003 ± 0.001</td><td>400 ± 50</td><td>ALDE</td><td>87</td><td>GAM4</td><td>100 π<sup>-</sup> p → 4π<sup>0</sup> n</td></tr></tbody></table>

$\Gamma(\gamma\gamma)/\Gamma(\pi\pi)$

$\Gamma_7/\Gamma$

<table><thead><tr><th>VALUE (units 10<sup>-5</sup>)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>1.57 ± 0.01<sup>+1.39</sup><sub>-0.14</sub></td><td>UEHARA</td><td>08A</td><td>BELL</td><td>10.6 e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> π<sup>0</sup> π<sup>0</sup></td></tr></tbody></table>

$\Gamma(\eta\pi\pi)/\Gamma(\pi\pi)$

$\Gamma_8/\Gamma_1$

<table><thead><tr><th>VALUE</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>&lt;0.010</td><td>95</td><td>EMMS</td><td>75d</td><td>DBC</td><td>4 π<sup>+</sup> n → p f<sub>2</sub></td></tr></tbody></table>

$\Gamma(K^0 K^- + \text{c.c.})/\Gamma(\pi\pi)$

$\Gamma_9/\Gamma_1$

<table><thead><tr><th>VALUE</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>&lt;0.004</td><td>95</td><td>EMMS</td><td>75d</td><td>DBC</td><td>4 π<sup>+</sup> n → p f<sub>2</sub></td></tr></tbody></table>

$\Gamma(e^+ e^-)/\Gamma(\pi\pi)$

$\Gamma_{10}/\Gamma$

<table><thead><tr><th>VALUE (units 10<sup>-10</sup>)</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>&lt;6</td><td>90</td><td>ACHASOV</td><td>00k</td><td>SND</td><td>e<sup>+</sup> e<sup>-</sup> → π<sup>0</sup> π<sup>0</sup></td></tr></tbody></table>

$f_2(1270)$ REFERENCES

<table><tbody><tr><td>KLEMP</td><td>22</td><td>PL B830 137171</td><td>E. Klempt et al.</td><td>(BONN)</td></tr><tr><td>RODAS</td><td>22</td><td>PL B82 80</td><td>A. Rodas et al.</td><td>(JPAC Collab.)</td></tr><tr><td>CARVER</td><td>20</td><td>PL 126 082002</td><td>M. Carver et al.</td><td>(CLAS Collab.)</td></tr><tr><td>ALBRECHT</td><td>20</td><td>EPJ C80 453</td><td>M. Albrecht et al.</td><td>(Crystal Barrel Collab.)</td></tr><tr><td>DOBBS</td><td>15</td><td>PR D91 052006</td><td>S. Dobbs et al.</td><td>(NWES)</td></tr><tr><td>DAI</td><td>14a</td><td>PR D90 036004</td><td>L.-Y. Dai, M.R. Pennington</td><td>(CEBAF)</td></tr><tr><td>BOGOLYUB...</td><td>13</td><td>PL 76 1324</td><td>M.Yu. Bogolyubsky et al.</td><td>(HYPERON-M Collab.)</td></tr><tr><td>UEHARA</td><td>13</td><td>PTEP 2013 123C01</td><td>Translated from YAF 76 1389.</td><td></td></tr><tr><td>UEHARA</td><td>10A</td><td>PR D82 114031</td><td>S. Uehara et al.</td><td>(BELLE Collab.)</td></tr><tr><td>ANISOVICH</td><td>09</td><td>UMP A24 2481</td><td>S. Uehara et al.</td><td>(BELLE Collab.)</td></tr><tr><td>UEHARA</td><td>09</td><td>PR D79 052009</td><td>S. Uehara et al.</td><td>(PNPI)</td></tr><tr><td>PDG</td><td>08</td><td>PL B667 1</td><td>C. Amsler et al.</td><td>(PDG Collab.)</td></tr><tr><td>PENNINGTON</td><td>08</td><td>EPJ C56 1</td><td>M.R. Pennington et al.</td><td></td></tr><tr><td>UEHARA</td><td>08A</td><td>PR D78 052004</td><td>S. Uehara et al.</td><td>(BELLE Collab.)</td></tr><tr><td>MORI</td><td>07</td><td>PR D75 051101</td><td>M. Ablikim et al.</td><td>(BELLE Collab.)</td></tr><tr><td>ABLIKIM</td><td>06V</td><td>PR B642 441</td><td>S. Ablikim et al.</td><td>(BES Collab.)</td></tr><tr><td>SCHEGELSKY</td><td>06A</td><td>EPJ A27 207</td><td>V.A. Schegelsky et al.</td><td></td></tr><tr><td>ABLIKIM</td><td>05</td><td>PL B607 243</td><td>M. Ablikim et al.</td><td>(BES Collab.)</td></tr><tr><td>BINON</td><td>05</td><td>PAN 68 960</td><td>F. Binon et al.</td><td></td></tr><tr><td>ABLIKIM</td><td>04E</td><td>Translated from YAF 68 998.</td><td>M. Ablikim et al.</td><td>(BES Collab.)</td></tr><tr><td>BARGIOTTI</td><td>03</td><td>EPJ C26 371</td><td>M. Bargiotti et al.</td><td>(OBELIX Collab.)</td></tr><tr><td>TIKHIOMIROV</td><td>03</td><td>PAN 66 828</td><td>G.D. Tikhomirov et al.</td><td></td></tr><tr><td>ACHASOV</td><td>00K</td><td>PL B492 8</td><td>M.N. Achasov et al.</td><td>(Novosibirsk. SR Collab.)</td></tr><tr><td>BARBERIS</td><td>00E</td><td>PL B47 59</td><td>D. Barberis et al.</td><td>(WA 102 Collab.)</td></tr><tr><td>BOGIONE</td><td>99</td><td>EPJ C9 11</td><td>M. Boglione, M.R. Pennington</td><td></td></tr><tr><td>ALDE</td><td>98</td><td>EPJ A3 361</td><td>D. Alde et al.</td><td>(GAM4 Collab.)</td></tr><tr><td>Also</td><td></td><td>PAN 62 405</td><td>D. Alde et al.</td><td>(GAMS Collab.)</td></tr><tr><td>ALDE</td><td>97</td><td>PL B397 350</td><td>Translated from YAF 62 446.</td><td></td></tr><tr><td>BERTIN</td><td>97</td><td>PL B408 476</td><td>D.M. Alde et al.</td><td>(GAMS Collab.)</td></tr><tr><td>GRYGOREV</td><td>96</td><td>PAN 59 2105</td><td>A. Bertin et al.</td><td>(OBELIX Collab.)</td></tr><tr><td>YABUKI</td><td>95</td><td>Translated from YAF 59 2187.</td><td>V.K. Grigoriev, O.N. Baloshin, B.P. Barkov</td><td>(ITEP)</td></tr><tr><td>PROKOSHKIN</td><td>94</td><td>JPS 64 435</td><td>F. Yabuki et al.</td><td>(VENUS Collab.)</td></tr><tr><td></td><td></td><td>PD 39 420</td><td>Y.D. Prokoshkin, A.A. Kondashov</td><td>(SERP)</td></tr><tr><td>BEHREND</td><td>92</td><td>ZPHY C56 381</td><td>Translated from DANS 336 613.</td><td></td></tr><tr><td>BILOVIN</td><td>92</td><td>ZPHY C53 33</td><td>H.J. Behrend</td><td>(CELLO Collab.)</td></tr><tr><td>AGUILAR...</td><td>92</td><td>ZPHY C50 405</td><td>A.E. Bilovin et al.</td><td>(NOVO)</td></tr><tr><td>AKER</td><td>91</td><td>PL B264 249</td><td>M. Aguilar-Benitez et al.</td><td>(LEBC-EHS Collab.)</td></tr><tr><td>ADACHI</td><td>90</td><td>PL B230 185</td><td>E. Aker et al.</td><td>(Crystal Barrel Collab.)</td></tr><tr><td>ALBRECHT</td><td>90G</td><td>ZPHY C48 183</td><td>I. Adachi et al.</td><td>(TOPAZ Collab.)</td></tr><tr><td>BOYER</td><td>90</td><td>PL D42 1350</td><td>H. Albrecht et al.</td><td>(ARGUS Collab.)</td></tr><tr><td>BREASTSTONE</td><td>90</td><td>PR B41 569</td><td>J. Boyer et al.</td><td>(Mark II Collab.)</td></tr><tr><td>MARSISKE</td><td>90</td><td>A.M. Breakstone et al.</td><td>A.M. Breakstone et al.</td><td>(ISU, BGNA, CERN-B)</td></tr><tr><td>MORGAN</td><td>90</td><td>PR D41 3324</td><td>H. Marsiske et al.</td><td>(Crystal Ball Collab.)</td></tr><tr><td>OEST</td><td>90</td><td>PR C48 623</td><td>D. Morgan, M.R. Pennington</td><td>(RAL, DURH)</td></tr><tr><td>OEST</td><td>90</td><td>ZPHY C47 343</td><td>T. Oest et al.</td><td>(JADE Collab.)</td></tr><tr><td>AUGUSTIN</td><td>89</td><td>NP B320 1</td><td>J.E. Augustin, G. Cosme</td><td>(DM2 Collab.)</td></tr><tr><td>VOROBYEV</td><td>88</td><td>NP B48 273</td><td>P.Y. Vorobiev et al.</td><td>(NOVO)</td></tr><tr><td>ALDE</td><td>87</td><td>PL B198 286</td><td>Translated from YAF 48 436.</td><td></td></tr><tr><td>AUGUSTIN</td><td>87</td><td>ZPHY C36 369</td><td>D.M. Alde et al.</td><td>(LANL, BRUX, SERP, LAPP)</td></tr><tr><td>ABACHI</td><td>86B</td><td>PL R1 5990</td><td>J.E. Augustin et al.</td><td>(LALO, CLER, FRAS+)</td></tr><tr><td>ALHARA</td><td>86B</td><td>PL C2C 54</td><td>S. Abachi et al.</td><td>(PURD, ANL, IND, MICH+)</td></tr><tr><td>ALDE</td><td>86</td><td>NP B269 485</td><td>H. Alhara et al.</td><td>(LEBC-EHS Collab.)</td></tr><tr><td>LANDRO</td><td>86D</td><td>PL P172 445</td><td>D. Alde et al.</td><td>(BEL, LAPP, SERP, CERN+)</td></tr><tr><td>LONGACRE</td><td>86</td><td>PL B177 223</td><td>M. Landro, K.J. Mork, H.A. Olsen</td><td>(UTRO)</td></tr><tr><td>LYTH</td><td>86</td><td>PL G11 459</td><td>R.S. Longacre et al.</td><td>(BNL, BRAN, CUNY+)</td></tr><tr><td>BEHREND</td><td>84B</td><td>ZPHY C23 223</td><td>D.H. Lyth</td><td></td></tr><tr><td>BERGER</td><td>84</td><td>ZPHY C26 199</td><td>H.J. Behrend et al.</td><td>(CELLO Collab.)</td></tr><tr><td>COURAU</td><td>84</td><td>ZPHY C16 107</td><td>C. Berger et al.</td><td>(PLUTO Collab.)</td></tr><tr><td>SMITH</td><td>84C</td><td>PR 147B 227</td><td>A. Courau et al.</td><td>(CIT, SLAC)</td></tr><tr><td>BINON</td><td>84C</td><td>PR D30 851</td><td>J.R. Smith et al.</td><td>(SLAC, LBL, HARV)</td></tr><tr><td>Also</td><td></td><td>NC 78A 313</td><td>F.G. Binon et al.</td><td>(BELG, LAPP, SERP+)</td></tr><tr><td>CHABAUD</td><td>83</td><td>SJNP 38 561</td><td>F.G. Binon et al.</td><td>(BELG, LAPP, SERP+)</td></tr><tr><td>DENNEY</td><td>83</td><td>PL B223 1</td><td>Translated from YAF 38 934.</td><td></td></tr><tr><td>MEENNESSIER</td><td>83</td><td>PR D28 2726</td><td>V. Chabaud et al.</td><td>(CERN, CRAC, MPIM)</td></tr><tr><td>APEL</td><td>83</td><td>ZPHY C16 241</td><td>D. L. Denney et al.</td><td>(IOWA, MICH)</td></tr><tr><td>CASON</td><td>82</td><td>PR D15 197</td><td>G. Mennesser</td><td>(MONP)</td></tr><tr><td>EDWARDS</td><td>82F</td><td>PL 48 1316</td><td>W.D. Apel et al.</td><td>(KARLK, KARLE, PISA, SERP+)</td></tr><tr><td>ETKIN</td><td>82B</td><td>PR D25 1786</td><td>N.M. Cason et al.</td><td>(NDAM, ANL)</td></tr><tr><td>BRANDELIK</td><td>81B</td><td>ZPHY C10 117</td><td>C. Edwards et al.</td><td>(CIT, HARV, PRIN+)</td></tr><tr><td>CHABAUD</td><td>81</td><td>APP B15 575</td><td>A. Etkin et al.</td><td>(BNL, CUNY, TUFTS, VAND)</td></tr><tr><td>GIDAL</td><td>81</td><td>PL 107B 153</td><td>R. Brandelik et al.</td><td>(TASSO Collab.)</td></tr><tr><td>ROUSSARIE</td><td>81</td><td>PL 105B 304</td><td>V. Chabaud et al.</td><td>(CERN, CRAC, MPIM)</td></tr><tr><td>BERGER</td><td>80B</td><td>PL 94B 254</td><td>G. Gidal et al.</td><td>(SLAC, LBL)</td></tr><tr><td>COSTA</td><td>80</td><td>NP B175 402</td><td>A. Roussarie et al.</td><td>(SLAC, LBL)</td></tr><tr><td>LOVERRE</td><td>80</td><td>ZPHY C6 187</td><td>C. Berger et al.</td><td>(PLUTO Collab.)</td></tr><tr><td>CORDEN</td><td>80</td><td>NP B157 250</td><td>G. Costa et al.</td><td>(BARI, BONN, CERN, GLAS+)</td></tr><tr><td>MARTIN</td><td>79</td><td>NP B158 520</td><td>P.F. Loverre et al.</td><td>(CERN, CDEF, MADR+)</td></tr><tr><td>POLYCHRO...</td><td>79</td><td>PR D19 1317</td><td>M.J. Corden et al.</td><td>(BIRM, RHEL, TELA-)</td></tr><tr><td>PDG</td><td>78</td><td>PL 75B 1</td><td>A.D. Martin, E.N. Ozmutlu</td><td>(DURH)</td></tr><tr><td>ANTIPOV</td><td>77</td><td>NP B119 45</td><td>V.A. Polychronakos et al.</td><td>(NDAM, ANL)</td></tr><tr><td>PAWLICKI</td><td>77</td><td>PR D15 1396</td><td>C. Bricman et al.</td><td></td></tr><tr><td>DEUTSCH...</td><td>76</td><td>NP B103 426</td><td>Y.M. Antipov et al.</td><td>(SERP, GEVA)</td></tr><tr><td>APEL</td><td>75</td><td>PL 57B 398</td><td>A.J. Pawlicki et al.</td><td>(ANL)</td></tr><tr><td>EMMS</td><td>75D</td><td>NP B96 155</td><td>Deutschmann et al.</td><td>(AACH3, BERL, BONN+)</td></tr><tr><td>HYAMS</td><td>75</td><td>NP B100 205</td><td>W.D. Apel et al.</td><td>(KARLK, KARLE, PISA, SERP+)</td></tr><tr><td>EISENBERG</td><td>74</td><td>NP B152 290</td><td>M.J. Emmas et al.</td><td>(BIRM, DURH, RHEL)</td></tr><tr><td>ENGLER</td><td>74</td><td>PR D14 2070</td><td>B.D. Hyams et al.</td><td>(CERN, MPIM)</td></tr><tr><td>LOUIE</td><td>74</td><td>PL 48B 385</td><td>A. Engler et al.</td><td>(CMU, CASE)</td></tr><tr><td>PDG</td><td>74</td><td>PL 50B 1</td><td>J. Louie et al.</td><td>(SACL, CERN)</td></tr><tr><td>ANDERSON</td><td>73</td><td>PL R1 31 562</td><td>V. Chaloupka et al.</td><td></td></tr><tr><td>TAKAHASHI</td><td>72</td><td>PR D6 1266</td><td>J.C. Anderson et al.</td><td>(CMU, CASE)</td></tr><tr><td>BEAUPRE</td><td>71</td><td>PL B26 77</td><td>K. Takahashi et al.</td><td>(TOHOK, PENN, NDAM+)</td></tr><tr><td>FLATTE</td><td>71</td><td>PL 34B 551</td><td>J.V. Beaupre et al.</td><td>(AACH, BERL, CERN)</td></tr><tr><td>ARMENISE</td><td>70</td><td>LNC 4 199</td><td>S.M. Flatte et al.</td><td>(LBL)</td></tr><tr><td>OH</td><td>70</td><td>CNC 199</td><td>N. Armisen et al.</td><td>(BARI, BGNA, FIRZ)</td></tr><tr><td>STUNTEBECK</td><td>70</td><td>PR D1 2494</td><td>B.Y. Oh et al.</td><td>(WISC, TINTO) JP</td></tr><tr><td>ADERHOLZ</td><td>70</td><td>PL 32B 391</td><td>P.H. Stuntebeck et al.</td><td>(NDAM)</td></tr><tr><td>ARMENISE</td><td>69</td><td>PR B14 259</td><td>M. Aderholz et al.</td><td>(AACH3, BERL, CERN+)</td></tr><tr><td>ASCOLI</td><td>68D</td><td>NC 54A 999</td><td>N. Armenise et al.</td><td>(BARI, BGNA, FIRZ+)</td></tr><tr><td>BOESEBECK</td><td>68</td><td>NP B4 501</td><td>G. Ascoli et al.</td><td>(ILL)</td></tr><tr><td>JOHNSON</td><td>68</td><td>PR 176 1651</td><td>K. Boesebeck et al.</td><td>(AACH, BERL, CERN)</td></tr><tr><td>EISNER</td><td>67</td><td>PR 164 1699</td><td>R.L. Eisner et al.</td><td>(NDAM, PURD)</td></tr><tr><td>DERADO</td><td>65</td><td>PR 14 872</td><td>I. Derado et al.</td><td>(NDAM)</td></tr><tr><td>LEE</td><td>64</td><td>PL 12 342</td><td>Y.Y. Lee et al.</td><td>(MICH)</td></tr><tr><td>BONDAR</td><td>63</td><td>PL 5 153</td><td>L. Bondar et al.</td><td>(AACH, BIRM, BONN, DESY+)</td></tr></tbody></table>
$f_1(1285)$

$I^G(JPC) = 0^+(1++)$

$f_1(1285)$ MASS

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>1281.8 ± 0.5 OUR AVERAGE</strong></td></tr><tr><td colspan="5">Error Includes scale factor of 1.7. See the ideogram below.</td></tr><tr><td>1280.2 ± 0.6 <sup>+ 1.2</sup><sub>- 1.5</sub></td><td>126K</td><td>ABLIKIM</td><td>23M</td><td>BES3 J/ψ → γK<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub>π<sup>0</sup></td></tr><tr><td>1281.0 ± 0.8</td><td></td><td>DICKSON</td><td>16</td><td>CLAS 2.55 γp → ηπ<sup>+</sup>π<sup>-</sup> p</td></tr><tr><td>1287.4 ± 3.0</td><td>87</td><td>ABLIKIM</td><td>15P</td><td>BES3 J/ψ → K<sup>+</sup> K<sup>-</sup> 3π</td></tr><tr><td>1281.16 ± 0.39 ± 0.45</td><td></td><td>1 LEES</td><td>12X</td><td>BABR τ<sup>-</sup> → π<sup>-</sup> f<sub>1</sub>(1285)ν<sub>τ</sub></td></tr><tr><td>1285.1 ± 1.0 <sup>+ 1.6</sup><sub>- 0.3</sub></td><td></td><td>2 ABLIKIM</td><td>11J</td><td>BES3 J/ψ → ω(ηπ<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>1281 ± 2 ± 1</td><td></td><td>AUBERT</td><td>07AU</td><td>BABR 10.6 e<sup>+</sup> e<sup>-</sup> → f<sub>1</sub>(1285)π<sup>+</sup>π<sup>-</sup> γ</td></tr><tr><td>1276.1 ± 8.1 ± 8.0</td><td>203</td><td>BAI</td><td>04J</td><td>BES2 J/ψ → γγπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1274 ± 6</td><td>237</td><td>ABDALLAH</td><td>03H</td><td>DLPH 91.2 e<sup>+</sup> e<sup>-</sup> → K<sup>0</sup><sub>S</sub>K<sup>±</sup>π<sup>+</sup> + X</td></tr><tr><td>1280 ± 4</td><td></td><td>ACCIARRI</td><td>01G</td><td>L3</td></tr><tr><td>1288 ± 4 ± 5</td><td>20k</td><td>ADAMS</td><td>01B</td><td>B852 18 GeV π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>1284 ± 6</td><td></td><td>ALDE</td><td>97B</td><td>GM4 100 π<sup>-</sup> p → ηπ<sup>0</sup> π<sup>0</sup> n</td></tr><tr><td>1281 ± 1</td><td>1400</td><td>BARBERIS</td><td>97B</td><td>OMEG 450 pp → pp2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>1281 ± 1</td><td></td><td>BARBERIS</td><td>97C</td><td>OMEG 450 pp → ppK<sup>0</sup><sub>S</sub>K<sup>±</sup>π<sup>+</sup></td></tr><tr><td>1280 ± 2</td><td></td><td>3 ANTINORI</td><td>95</td><td>OMEG 300,450 pp → pp2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>1282.2 ± 1.5</td><td></td><td>LEE</td><td>94</td><td>MPS2 18 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> 2π<sup>-</sup> p</td></tr><tr><td>1279 ± 5</td><td></td><td>FUKUI</td><td>91C</td><td>SPEC 8.95 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td></tr><tr><td>1278 ± 2</td><td>140</td><td>ARMSTRONG</td><td>89</td><td>OMEG 300 pp → K<sup>+</sup> K<sup>-</sup> pp</td></tr><tr><td>1278 ± 2</td><td></td><td>ARMSTRONG</td><td>89G</td><td>OMEG 85 π<sup>+</sup> p → 4ππp, pp → 4πpp</td></tr><tr><td>1280.1 ± 2.1</td><td>60</td><td>RATH</td><td>89</td><td>MPS 21.4 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub>π<sup>0</sup> n</td></tr><tr><td>1285 ± 1</td><td>4750</td><td>4 BIRMAN</td><td>88</td><td>MPS 8 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>1280 ± 1</td><td>504</td><td>BITYUKOV</td><td>88</td><td>SPEC 32.5 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>1280 ± 4</td><td></td><td>ANDO</td><td>86</td><td>SPEC 8 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td></tr><tr><td>1277 ± 2</td><td>420</td><td>REEVES</td><td>86</td><td>SPEC 6.6 p p → K KπX</td></tr><tr><td>1285 ± 2</td><td></td><td>CHUNG</td><td>85</td><td>SPEC 8 π<sup>-</sup> p → N K<sup>+</sup> Kπ</td></tr><tr><td>1279 ± 2</td><td>604</td><td>ARMSTRONG</td><td>84</td><td>OMEG 85 π<sup>+</sup> p → K<sup>+</sup> K<sup>-</sup> ππp, pp → K<sup>+</sup> K<sup>-</sup> pp</td></tr><tr><td>1286 ± 4</td><td></td><td>CHAUVAT</td><td>84</td><td>SPEC ISR 31.5 pp</td></tr><tr><td>1278 ± 4</td><td></td><td>EVANGELIS...</td><td>81</td><td>OMEG 12 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> π<sup>-</sup> p</td></tr><tr><td>1283 ± 3</td><td>103</td><td>DIONISI</td><td>80</td><td>HBC 4 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> πn</td></tr><tr><td>1282 ± 2</td><td>320</td><td>NACASCH</td><td>78</td><td>HBC 0.7,0.76 p p → K<sup>+</sup> K<sup>-</sup> 3π</td></tr><tr><td>1279 ± 5</td><td>210</td><td>GRASSLER</td><td>77</td><td>16 π<sup>+</sup> p</td></tr><tr><td>1286 ± 3</td><td>180</td><td>DUBOC</td><td>72</td><td>HBC 1.2 p p → 2K 4π</td></tr><tr><td>1283 ± 5</td><td></td><td>DAHL</td><td>67</td><td>HBC 1.6-4.2 π<sup>-</sup></td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>1289.3 ± 2.8</td><td>234</td><td>ABLIKIM</td><td>19BA</td><td>BES3 e<sup>+</sup> e<sup>-</sup> → ψ(2S)</td></tr><tr><td>1284.2 ± 2.2</td><td></td><td>5 AAIJ</td><td>14Y</td><td>LHCB (s) → J/ψ2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>1281.9 ± 0.5</td><td></td><td>5 SOSA</td><td>99</td><td>SPEC pp → p<sub>slow</sub>(K<sup>0</sup><sub>S</sub> K<sup>+</sup> π<sup>-</sup>) p<sub>fast</sub></td></tr><tr><td>1282.8 ± 0.6</td><td></td><td>5 SOSA</td><td>99</td><td>SPEC pp → p<sub>slow</sub>(K<sup>0</sup><sub>S</sub> K<sup>+</sup> π<sup>+</sup>) p<sub>fast</sub></td></tr><tr><td>1270 ± 10</td><td></td><td>AMELIN</td><td>95</td><td>VES 37 π<sup>-</sup> N<sup>-</sup> → π<sup>-</sup> π<sup>+</sup> π<sup>-</sup> γN</td></tr><tr><td>1280 ± 2</td><td></td><td>ABATZIS</td><td>94</td><td>OMEG 450 pp → pp2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>1282 ± 4</td><td></td><td>ARMSTRONG</td><td>93C</td><td>E760 p p → π<sup>0</sup> ηη → 6γ</td></tr><tr><td>1270 ± 6 ± 10</td><td></td><td>ARMSTRONG</td><td>92C</td><td>OMEG 300 pp → ppπ<sup>+</sup> π<sup>-</sup> γ</td></tr><tr><td>1281 ± 1</td><td></td><td>ARMSTRONG</td><td>89E</td><td>OMEG 300 pp → pp2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>1279 ± 6 ± 10</td><td>16</td><td>BECKER</td><td>87</td><td>MRK3 e<sup>+</sup> e<sup>-</sup> → φK Kπ</td></tr><tr><td>1286 ± 9</td><td></td><td>GIDAL</td><td>87</td><td>MRK2 e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> → ηπ<sup>+</sup> π<sup>-</sup></td></tr><tr><td>1287 ± 5</td><td>353</td><td>BITYUKOV</td><td>84B</td><td>SPEC 32 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>~ 1279</td><td></td><td>6 TORNQVIST</td><td>82B</td><td>RVUE</td></tr><tr><td>1275 ± 6</td><td>31</td><td>BROMBERG</td><td>80</td><td>SPEC 100 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> πX</td></tr><tr><td>1288 ± 9</td><td>200</td><td>GURTU</td><td>79</td><td>HBC 4.2 K<sup>-</sup> p → nη2π</td></tr><tr><td>~ 1275.0</td><td>46</td><td>7 STANTON</td><td>79</td><td>CNTR 8.5 π<sup>-</sup> p → n2γ2π</td></tr><tr><td>1271 ± 10</td><td>34</td><td>CORDEN</td><td>78</td><td>OMEG 12-15 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> πn</td></tr><tr><td>1295 ± 12</td><td>85</td><td>CORDEN</td><td>78</td><td>OMEG 12-15 π<sup>-</sup> p → n5π</td></tr><tr><td>1292 ± 10</td><td>150</td><td>DEFOIX</td><td>72</td><td>HBC 0.7 p p → 7π</td></tr><tr><td>1280 ± 3</td><td>500</td><td>8 THUN</td><td>72</td><td>MMS 13.4 π<sup>-</sup> p</td></tr><tr><td>1303 ± 8</td><td></td><td>BARDADIN...</td><td>71</td><td>HBC 8 π<sup>+</sup> p → p6π</td></tr><tr><td>1283 ± 6</td><td></td><td>BOESEBECK</td><td>71</td><td>HBC 16.0 π p → p5π</td></tr><tr><td>1270 ± 10</td><td></td><td>CAMPBELL</td><td>69</td><td>DBC 2.7 π<sup>+</sup> d</td></tr><tr><td>1285 ± 7</td><td></td><td>LORSTAD</td><td>69</td><td>HBC 0.7 p p, 4,5-body</td></tr><tr><td>1290 ± 7</td><td></td><td>D'ANDLAU</td><td>68</td><td>HBC 1.2 p p, 5-6 body</td></tr></tbody></table>

WEIGHTED AVERAGE
1281.8±0.5 (Error scaled by 1.7)

<figure><img src="image_454.png" /><figcaption>$f_1(1285)$ mass (MeV)</figcaption></figure>

$f_1(1285)$ WIDTH

Only experiments giving width error less than 20 MeV are kept for averaging.

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>23.0 ± 1.1 OUR AVERAGE</strong></td></tr><tr><td>28.2 ± 1.1 <sup>+ 5.5</sup><sub>- 2.9</sub></td><td>126K</td><td>ABLIKIM</td><td>23M</td><td>BES3 J/ψ → γK<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub>π<sup>0</sup></td></tr><tr><td>18.4 ± 1.4</td><td></td><td>DICKSON</td><td>16</td><td>CLAS 2.55 γp → ηπ<sup>+</sup> π<sup>-</sup> p</td></tr><tr><td>18.3 ± 6.3</td><td>87</td><td>ABLIKIM</td><td>15P</td><td>BES3 J/ψ → K<sup>+</sup> K<sup>-</sup> 3π</td></tr><tr><td>22.0 ± 3.1 <sup>+ 2.0</sup><sub>- 1.5</sub></td><td></td><td>1 ABLIKIM</td><td>11J</td><td>BES3 J/ψ → ω(ηπ<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>35 ± 6 ± 4</td><td></td><td>AUBERT</td><td>07AU</td><td>BABR 10.6 e<sup>+</sup> e<sup>-</sup> → f<sub>1</sub>(1285)π<sup>+</sup> π<sup>-</sup> γ</td></tr><tr><td>40.0 ± 8.6 ± 9.3</td><td>203</td><td>BAI</td><td>04J</td><td>BES2 J/ψ → γγπ<sup>+</sup> π<sup>-</sup></td></tr><tr><td>29 ± 12</td><td>237</td><td>ABDALLAH</td><td>03H</td><td>DLPH 91.2 e<sup>+</sup> e<sup>-</sup> → K<sup>0</sup><sub>S</sub>K<sup>±</sup>π<sup>+</sup> + X</td></tr><tr><td>45 ± 9 ± 7</td><td>20k</td><td>ADAMS</td><td>01B</td><td>B852 18 GeV π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>55 ± 18</td><td>1400</td><td>ALDE</td><td>97B</td><td>GAM4 100 π<sup>-</sup> p → ηπ<sup>0</sup> π<sup>0</sup> n</td></tr><tr><td>24 ± 3</td><td></td><td>BARBERIS</td><td>97B</td><td>OMEG 450 pp → pp2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>20 ± 2</td><td></td><td>BARBERIS</td><td>97C</td><td>OMEG 450 pp → ppK<sup>0</sup><sub>S</sub>K<sup>±</sup>π<sup>+</sup></td></tr><tr><td>36 ± 5</td><td></td><td>2 ANTINORI</td><td>95</td><td>OMEG 300,450 pp → pp2(π<sup>+</sup> π<sup>-</sup>)</td></tr><tr><td>29.0 ± 4.1</td><td></td><td>LEE</td><td>94</td><td>MPS2 18 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> 2π<sup>-</sup> p</td></tr><tr><td>25 ± 4</td><td>140</td><td>ARMSTRONG</td><td>89</td><td>OMEG 300 pp → K<sup>+</sup> K<sup>-</sup> pp</td></tr><tr><td>22 ± 2</td><td>4750</td><td>3 BIRMAN</td><td>88</td><td>MPS 8 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>25 ± 4</td><td>504</td><td>BITYUKOV</td><td>88</td><td>SPEC 32.5 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>19 ± 5</td><td></td><td>ANDO</td><td>86</td><td>SPEC 8 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td></tr><tr><td>32 ± 8</td><td>420</td><td>REEVES</td><td>86</td><td>SPEC 6.6 p p → K KπX</td></tr><tr><td>22 ± 2</td><td></td><td>CHUNG</td><td>85</td><td>SPEC 8 π<sup>-</sup> p → N K<sup>+</sup> K<sup>-</sup> π</td></tr><tr><td>32 ± 3</td><td>604</td><td>ARMSTRONG</td><td>84</td><td>OMEG 85 π<sup>+</sup> p → K<sup>+</sup> K<sup>-</sup> ππp, pp → K<sup>+</sup> K<sup>-</sup> pp</td></tr><tr><td>24 ± 3</td><td></td><td>CHAUVAT</td><td>84</td><td>SPEC ISR 31.5 pp</td></tr><tr><td>29 ± 10</td><td>103</td><td>DIONISI</td><td>80</td><td>HBC 4 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> πn</td></tr><tr><td>28.3 ± 6.7</td><td>320</td><td>NACASCH</td><td>78</td><td>HBC 0.7,0.76 p p → K<sup>+</sup> K<sup>-</sup> 3π</td></tr></tbody></table>

<footnote n="1">¹ Using the $2\pi^+ 2\pi^-$ and $\pi^+ \pi^- \eta$ modes of $f_1(1285)$ decay.</footnote>

<footnote n="2">² The selected process is $J/\psi \to \omega a_0(980)\pi$.</footnote>

<footnote n="3">³ Supersedes ABATZIS 94, ARMSTRONG 89E.</footnote>

<footnote n="4">⁴ From partial wave analysis of $K^+ K^0 \pi^-$ system.</footnote>

<footnote n="5">⁵ No systematic error given.</footnote>

<footnote n="6">⁶ From a unitarized quark-model calculation.</footnote>

<footnote n="7">⁷ From phase shift analysis of $\eta\pi^+\pi^-$ system.</footnote>

<footnote n="8">⁸ Seen in the missing mass spectrum.</footnote>
# Meson Particle Listings

$f_1(1285)$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>17.1 ± 3.4</td><td>234</td><td>ABLIKIM</td><td>19BA BES3</td><td>e<sup>+</sup>e<sup>-</sup> → ψ(2S)</td></tr><tr><td>32.4 ± 5.8</td><td></td><td>4 AAIJ</td><td>14Y LHCB</td><td>B<sup>0</sup><sub>S</sub> → J/ψ2(π<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>18.2 ± 1.2</td><td></td><td>4 SOSA</td><td>99 SPEC</td><td>pp → p<sub>slow</sub>(K<sup>0</sup><sub>S</sub>K<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>19.4 ± 1.5</td><td></td><td>4 SOSA</td><td>99 SPEC</td><td>p<sub>fast</sub> → p<sub>slow</sub>(K<sup>0</sup><sub>S</sub>K<sup>-</sup>π<sup>+</sup>)</td></tr><tr><td></td><td></td><td></td><td></td><td>p<sub>fast</sub></td></tr><tr><td>40 ± 5</td><td></td><td>ABATZIS</td><td>94</td><td>OMEG 450 pp → pp2(π<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>31 ± 5</td><td></td><td>ARMSTRONG</td><td>89E</td><td>OMEG 300 pp → pp2(π<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>41 ± 12</td><td></td><td>ARMSTRONG</td><td>89G</td><td>OMEG 85 π<sup>+</sup> p → 4ππp, pp → 4πpp</td></tr><tr><td>17.9 ± 10.9</td><td>60</td><td>RATH</td><td>89</td><td>MPS 21.4 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub>K<sup>0</sup><sub>S</sub>π<sup>0</sup> n</td></tr><tr><td>14 <sup>+20</sup><sub>-14</sub> ± 10</td><td>16</td><td>BECKER</td><td>87</td><td>MRK3 e<sup>+</sup>e<sup>-</sup> → φK<sup>-</sup>K<sup>+</sup></td></tr><tr><td>26 ± 12</td><td></td><td>EVANGELIS...</td><td>81</td><td>OMEG 12 π<sup>-</sup> p → ηπ<sup>+</sup>π<sup>-</sup>π<sup>-</sup> p</td></tr><tr><td>25 ± 15</td><td>200</td><td>GURTU</td><td>79</td><td>HBC 4.2 K<sup>-</sup> p → nη2π</td></tr><tr><td>~ 10</td><td></td><td>5 STANTON</td><td>79</td><td>CNTR 8.5 π<sup>-</sup> p → n2γ2π</td></tr><tr><td>24 ± 18</td><td>210</td><td>GRASSLER</td><td>77</td><td>HBC 16 π<sup>+</sup>p</td></tr><tr><td>28 ± 5</td><td>150</td><td>6 DEFOIX</td><td>72</td><td>HBC 0.7 p̄p → p̄7π</td></tr><tr><td>46 ± 9</td><td>180</td><td>6 DUBOC</td><td>72</td><td>HBC 1.2 p̄p → 2K4π</td></tr><tr><td>37 ± 5</td><td>500</td><td>7 THUN</td><td>72</td><td>MMS 13.4 π<sup>-</sup> p</td></tr><tr><td>10 ± 10</td><td></td><td>BOESEBECK</td><td>71</td><td>HBC 16.0 πp → p5π</td></tr><tr><td>30 ± 15</td><td></td><td>CAMPBELL</td><td>69</td><td>DBC 2.7 π<sup>+</sup>d</td></tr><tr><td>60 ± 15</td><td></td><td>6 LORSTAD</td><td>69</td><td>HBC 0.7 p̄p, 4,5-body</td></tr><tr><td>35 ± 10</td><td></td><td>6 DAHL</td><td>67</td><td>HBC 1.6-4.2 π<sup>-</sup> p</td></tr></tbody></table>

¹ The selected process is J/ψ → ωa₀(980)π.

² Supersedes ABATZIS 94, ARMSTRONG 89E.

³ From partial wave analysis of K<sup>+</sup>K<sup>-</sup>π<sup>-</sup> system.

⁴ No systematic error given.

⁵ From phase shift analysis of ηπ<sup>+</sup>π<sup>-</sup> system.

⁶ Resolution is not unfolded.

⁷ Seen in the missing mass spectrum.

WEIGHTED AVERAGE
23.0±1.1 (Error scaled by 1.6)

<figure><img src="image_455.png" /><figcaption>$f_1(1285)$ width (MeV)</figcaption></figure>

## $f_1(1285)$ DECAY MODES

<table><thead><tr><th>Mode</th><th>Fraction (Γ<sub>i</sub>/Γ)</th><th>Scale factor/<br>Confidence level</th></tr></thead><tbody><tr><td>Γ<sub>1</sub> 4π</td><td>(32.7 ± 1.8) %</td><td>S=1.2</td></tr><tr><td>Γ<sub>2</sub> π<sup>0</sup>π<sup>0</sup>π<sup>+</sup>π<sup>-</sup></td><td>(21.8 ± 1.2) %</td><td>S=1.2</td></tr><tr><td>Γ<sub>3</sub> 2π<sup>+</sup>2π<sup>-</sup></td><td>(10.9 ± 0.6) %</td><td>S=1.2</td></tr><tr><td>Γ<sub>4</sub> ρ<sup>0</sup>π<sup>+</sup>π<sup>-</sup></td><td>(10.9 ± 0.6) %</td><td>S=1.2</td></tr><tr><td>Γ<sub>5</sub> ρ<sup>0</sup>ρ<sup>0</sup></td><td>seen</td><td></td></tr><tr><td>Γ<sub>6</sub> 4π<sup>0</sup></td><td>&lt; 7 × 10<sup>-4</sup></td><td>CL=90%</td></tr><tr><td>Γ<sub>7</sub> ηπ<sup>+</sup>π<sup>-</sup></td><td>(35 ± 15) %</td><td></td></tr><tr><td>Γ<sub>8</sub> ηππ</td><td>(52.2 ± 1.9) %</td><td>S=1.2</td></tr><tr><td>Γ<sub>9</sub> a<sub>0</sub>(980)π [ignoring a<sub>0</sub>(980) → K<sup>-</sup>K<sup>+</sup>]</td><td>(38 ± 4) %</td><td></td></tr><tr><td>Γ<sub>10</sub> ηπππ [excluding a<sub>0</sub>(980)π]</td><td>(14 ± 4) %</td><td></td></tr><tr><td>Γ<sub>11</sub> K<sup>-</sup>K<sup>+</sup>π</td><td>(9.0 ± 0.4) %</td><td>S=1.1</td></tr><tr><td>Γ<sub>12</sub> K<sup>-</sup>K<sup>+</sup>(892)</td><td>not seen</td><td></td></tr><tr><td>Γ<sub>13</sub> π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td><td>(3.0 ± 0.9) × 10<sup>-3</sup></td><td></td></tr></tbody></table>

<table><tbody><tr><td>Γ<sub>14</sub> ρ<sup>±</sup>π<sup>∓</sup></td><td>&lt; 3.1 × 10<sup>-3</sup></td><td>CL=95%</td></tr><tr><td>Γ<sub>15</sub> γρ<sup>0</sup></td><td>(6.1 ± 1.0) %</td><td>S=1.7</td></tr><tr><td>Γ<sub>16</sub> φγ</td><td>(7.4 ± 2.6) × 10<sup>-4</sup></td><td></td></tr><tr><td>Γ<sub>17</sub> e<sup>+</sup>e<sup>-</sup></td><td>&lt; 9.4 × 10<sup>-9</sup></td><td>CL=90%</td></tr><tr><td>Γ<sub>18</sub> γγ<sup>*</sup></td><td></td><td></td></tr><tr><td>Γ<sub>19</sub> γγ</td><td></td><td></td></tr></tbody></table>

## CONSTRAINED FIT INFORMATION

An overall fit to 6 branching ratios uses 18 measurements and one constraint to determine 5 parameters. The overall fit has a $\chi^2 = 24.0$ for 14 degrees of freedom.

The following off-diagonal array elements are the correlation coefficients $\langle \delta x_i \delta x_j \rangle / (\delta x_i \delta x_j)$, in percent, from the fit to the branching fractions, $x_i \equiv \Gamma_i / \Gamma_{\text{total}}$. The fit constrains the $x_i$ whose labels appear in this array to sum to one.

<table><tbody><tr><td>x<sub>9</sub></td><td>-29</td></tr><tr><td>x<sub>10</sub></td><td>-12 -89</td></tr><tr><td>x<sub>11</sub></td><td>22 -9 -4</td></tr><tr><td>x<sub>15</sub></td><td>-24 -8 -3 -27</td></tr><tr><td></td><td>x<sub>1</sub> x<sub>9</sub> x<sub>10</sub> x<sub>11</sub></td></tr></tbody></table>

## $f_1(1285)$ $\Gamma(i)\Gamma(\gamma\gamma)/\Gamma(\text{total})$

<table><tbody><tr><td colspan="2"><b>Γ(ηππ) × Γ(γγ)/Γ<sub>total</sub></b></td><td colspan="2"><b>Γ<sub>8</sub>Γ<sub>19</sub>/Γ = (Γ<sub>9</sub>+Γ<sub>10</sub>)Γ<sub>19</sub>/Γ</b></td></tr><tr><td>VALUE (keV)</td><td>CL%</td><td>DOCUMENT ID</td><td>TECN</td></tr><tr><td><b>&lt;0.62</b></td><td>95</td><td>GIDAL</td><td>87</td></tr></tbody></table>

<table><tbody><tr><td colspan="2"><b>Γ(ηππ) × Γ(γγ*)/Γ<sub>total</sub></b></td><td colspan="2"><b>Γ<sub>8</sub>Γ<sub>18</sub>/Γ = (Γ<sub>9</sub>+Γ<sub>10</sub>)Γ<sub>18</sub>/Γ</b></td></tr><tr><td>VALUE (keV)</td><td>EVTS</td><td>DOCUMENT ID</td><td>TECN</td></tr><tr><td><b>1.4 ± 0.4</b></td><td><b>OUR AVERAGE</b></td><td>DOCUMENT ID</td><td>TECN</td></tr><tr><td colspan="4">Error includes scale factor of 1.4.</td></tr><tr><td>1.18 ± 0.25 ± 0.20</td><td>26</td><td>1,2 AIHARA</td><td>88B TPC</td></tr><tr><td>2.30 ± 0.61 ± 0.42</td><td></td><td>1,3 GIDAL</td><td>87 MRK2</td></tr><tr><td colspan="4">e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>ηπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td colspan="4">• • • We do not use the following data for averages, fits, limits, etc. • • •</td></tr><tr><td>1.8 ± 0.3 ± 0.3</td><td>420</td><td>4 ACHARD</td><td>02B L3</td></tr><tr><td colspan="4">183-209 e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>ηπ<sup>+</sup>π<sup>-</sup></td></tr></tbody></table>

¹ Assuming a p̄-pole form factor.

² Published value multiplied by ηππ branching ratio 0.49.

³ Published value divided by 2 and multiplied by the ηππ branching ratio 0.49.

⁴ Published value multiplied by the ηππ branching ratio 0.52.

## $f_1(1285)$ BRANCHING RATIOS

$$ \Gamma(K\bar{K}\pi)/\Gamma(4\pi) \qquad \Gamma_{11}/\Gamma_1 $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{0.274} \pm 0.017 \textbf{ OUR FIT} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{Error includes scale factor of 1.4.} \end{array} $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{0.271} \pm 0.016 \textbf{ OUR AVERAGE} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{Error includes scale factor of 1.2.} \end{array} $$

$$ \begin{array}{l} 0.265 \pm 0.014 \qquad 1 \text{ BARBERIS} \quad 97C \quad \text{OMEG} \quad 450 \, pp \rightarrow ppK_S^0 K^\pm \pi^\mp \end{array} $$

$$ \begin{array}{l} 0.28 \pm 0.05 \qquad 2 \text{ ARMSTRONG} \quad 89E \quad \text{OMEG} \quad 300 \, pp \rightarrow pp\Gamma_1(1285) \end{array} $$

$$ \begin{array}{l} 0.37 \pm 0.03 \pm 0.05 \qquad 3 \text{ ARMSTRONG} \quad 89G \quad \text{OMEG} \quad 85 \, \pi p \rightarrow 4\pi X \end{array} $$

¹ Using 2(π<sup>+</sup>π<sup>-</sup>) data from BARBERIS 97B.

² Assuming ρππ and a₀(980)π intermediate states.

³ $4\pi$ consistent with being entirely ρππ.

$$ \Gamma(\pi^0 \pi^0 \pi^+ \pi^-)/\Gamma_{\text{total}} \qquad \Gamma_2/\Gamma = \frac{3}{2}\Gamma_1/\Gamma $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{0.218} \pm 0.012 \textbf{ OUR FIT} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{Error includes scale factor of 1.2.} \end{array} $$

$$ \Gamma(2\pi^+ 2\pi^-)/\Gamma_{\text{total}} \qquad \Gamma_3/\Gamma = \frac{1}{2}\Gamma_1/\Gamma $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{0.109} \pm 0.006 \textbf{ OUR FIT} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{Error includes scale factor of 1.2.} \end{array} $$

$$ \Gamma(\rho^0 \pi^+ \pi^-)/\Gamma_{\text{total}} \qquad \Gamma_4/\Gamma = \frac{1}{2}\Gamma_1/\Gamma $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{0.109} \pm 0.006 \textbf{ OUR FIT} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{Error includes scale factor of 1.2.} \end{array} $$

$$ \Gamma(\rho^0 \pi^+ \pi^-)/\Gamma(2\pi^+ 2\pi^-) \qquad \Gamma_4/\Gamma_3 $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{seen} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{GRASSLER} \quad 77 \quad \text{HBC} \quad 16 \, \text{GeV} \pi \pm \rho \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

1.0 ± 0.4 GRASSLER 77 HBC 16 GeV π±ρ

$$ \Gamma(\rho^0 \rho^0)/\Gamma_{\text{total}} \qquad \Gamma_5/\Gamma $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{seen} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{BARBERIS} \quad 00C \quad 450 \, pp \rightarrow p_f 4\pi p_S \end{array} $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{seen} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{ALDE} \quad 87 \quad \text{GAM4} \quad 100 \, \pi^- p \rightarrow 4\pi^0 n \end{array} $$

$$ \Gamma(4\pi^0)/\Gamma_{\text{total}} \qquad \Gamma_6/\Gamma $$

$$ \begin{array}{l} \textbf{VALUE} (\text{units } 10^{-4}) \\ \textbf{CL%} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{ALDE} \quad 87 \quad \text{GAM4} \quad 100 \, \pi^- p \rightarrow 4\pi^0 n \end{array} $$

$$ \begin{array}{l} \textbf{VALUE} \\ \textbf{<T} \end{array} \qquad \begin{array}{l} \textbf{DOCUMENT ID} \\ \textbf{ALDE} \quad 87 \quad \text{GAM4} \quad 100 \, \pi^- p \rightarrow 4\pi^0 n \end{array} $$
$$ \Gamma(\pi^{+} \pi^{-} \pi^{0})/\Gamma(\eta\pi^{+} \pi^{-}) \qquad \Gamma_{13}/\Gamma_{7} $$

<table><thead><tr><th>VALUE (%)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.86 ± 0.16 ± 0.20</td><td>2.3k</td><td>1 DOROFEEV</td><td>11</td><td>VES π<sup>-</sup> N → π<sup>-</sup> f<sub>1</sub>(1285) N</td></tr></tbody></table>

¹Value obtained selecting the region corresponding to $f_0(980)$ in the $\pi^+\pi^-$ mass spectrum.

$$ \Gamma(\eta\pi\pi)/\Gamma_{\text{total}} \qquad \Gamma_8/\Gamma = (\Gamma_9+\Gamma_{10})/\Gamma $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th></tr></thead><tbody><tr><td>0.522 ± 0.019 OUR FIT</td><td>Error includes scale factor of 1.2.</td></tr></tbody></table>

$$ \Gamma(4\pi)/\Gamma(\eta\pi\pi) \qquad \Gamma_1/\Gamma_8 = \Gamma_1/(\Gamma_9+\Gamma_{10}) $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.63 ± 0.06 OUR FIT</td><td>Error includes scale factor of 1.2.</td><td></td><td></td></tr></tbody></table>

0.41 ± 0.14 OUR AVERAGE

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.37 ± 0.11 ± 0.11</td><td>BOLTON</td><td>92</td><td>MRK3 J/ψ → γf<sub>1</sub>(1285)</td></tr><tr><td>0.64 ± 0.40</td><td>GURTU</td><td>79</td><td>HBC 4.2 K<sup>-</sup> p</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.93 ± 0.30</td><td>1 GRASSLER</td><td>77</td><td>HBC 16 π<sup>+</sup> p</td></tr></tbody></table>

¹Assuming $\rho\pi\pi$ and $a_0(980)$ π intermediate states.

$$ \Gamma(2\pi^{+} 2\pi^{-})/\Gamma(\eta\pi\pi) \qquad \Gamma_{3}/\Gamma_{8} $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.28 ± 0.02 ± 0.02</td><td>1 LEES</td><td>12x</td><td>BABR τ<sup>-</sup> → π<sup>-</sup> f<sub>1</sub>(1285) ν<sub>τ</sub></td></tr></tbody></table>

¹Assuming $B(f_1(1285) \rightarrow \pi\pi\eta) = 3/2 B(f_1(1285) \rightarrow \pi^+\pi^-\eta)$.

$$ \Gamma(a_0(980)\pi \text{ [ignoring } a_0(980) \rightarrow K\bar{K}\text{]})/\Gamma(\eta\pi\pi) \qquad \Gamma_9/\Gamma_8 = \Gamma_9/(\Gamma_9+\Gamma_{10}) $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.72 ± 0.08 OUR FIT</td><td></td><td></td><td></td></tr><tr><td>0.72 ± 0.07 OUR AVERAGE</td><td></td><td></td><td></td></tr></tbody></table>

0.74 ± 0.02 ± 0.09

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.74 ± 0.15</td><td>DICKSON</td><td>16</td><td>CLAS γp → f<sub>1</sub>(1285) p</td></tr><tr><td>0.6 ± 0.3</td><td>GURTU</td><td>79</td><td>HBC 4.2 K<sup>-</sup> p</td></tr><tr><td>0.6 ± 0.3</td><td>CORDEN</td><td>78</td><td>OMEG 12–15 π<sup>-</sup> p</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>>0.69</td><td>95</td><td>ACHARD</td><td>02B L3 183–209 e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> ηπ<sup>+</sup> π<sup>-</sup></td></tr><tr><td>0.28 ± 0.07</td><td>ALDE</td><td>97B</td><td>GAM4 100 π<sup>-</sup> p → ηπ<sup>0</sup>π<sup>0</sup> n</td></tr><tr><td>1.0 ± 0.3</td><td>GRASSLER</td><td>77</td><td>HBC 16 π<sup>+</sup> p</td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>>0.69</td><td>95</td><td>ACHARD</td><td>02B L3 183–209 e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> ηπ<sup>+</sup> π<sup>-</sup></td></tr><tr><td>0.28 ± 0.07</td><td>ALDE</td><td>97B</td><td>GAM4 100 π<sup>-</sup> p → ηπ<sup>0</sup>π<sup>0</sup> n</td></tr><tr><td>1.0 ± 0.3</td><td>GRASSLER</td><td>77</td><td>HBC 16 π<sup>+</sup> p</td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.172 ± 0.011 OUR FIT</td><td></td><td></td><td></td></tr><tr><td>0.176 ± 0.012 OUR AVERAGE</td><td></td><td></td><td></td></tr></tbody></table>

$$ \Gamma(K\bar{K}\pi)/\Gamma(\eta\pi\pi) \qquad \Gamma_{11}/\Gamma_8 = \Gamma_{11}/(\Gamma_9+\Gamma_{10}) $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.216 ± 0.010 ± 0.031</td><td>DICKSON</td><td>16</td><td>CLAS γp → f<sub>1</sub>(1285) p</td></tr><tr><td>0.166 ± 0.01 ± 0.008</td><td>BARBERIS</td><td>98C</td><td>OMEG 450 pp → ρf<sub>1</sub>(1285) p<sub>S</sub></td></tr><tr><td>0.42 ± 0.15</td><td>GURTU</td><td>79</td><td>HBC 4.2 K<sup>-</sup> p</td></tr><tr><td>0.5 ± 0.2</td><td>1 CORDEN</td><td>78</td><td>OMEG 12–15 π<sup>-</sup> p</td></tr><tr><td>0.20 ± 0.08</td><td>2 DEFOIX</td><td>72</td><td>HBC 0.7 p̄p → 7π</td></tr><tr><td>0.16 ± 0.08</td><td>CAMPBELL</td><td>69</td><td>DBC 2.7 π<sup>+</sup> d</td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.166 ± 0.01 ± 0.008</td><td>BARBERIS</td><td>98C</td><td>OMEG 450 pp → ρf<sub>1</sub>(1285) p<sub>S</sub></td></tr><tr><td>0.42 ± 0.15</td><td>GURTU</td><td>79</td><td>HBC 4.2 K<sup>-</sup> p</td></tr><tr><td>0.5 ± 0.2</td><td>1 CORDEN</td><td>78</td><td>OMEG 12–15 π<sup>-</sup> p</td></tr><tr><td>0.20 ± 0.08</td><td>2 DEFOIX</td><td>72</td><td>HBC 0.7 p̄p → 7π</td></tr><tr><td>0.16 ± 0.08</td><td>CAMPBELL</td><td>69</td><td>DBC 2.7 π<sup>+</sup> d</td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.28 ± 0.07</td><td>ALDE</td><td>97B</td><td>GAM4 100 π<sup>-</sup> p → ηπ<sup>0</sup>π<sup>0</sup> n</td></tr><tr><td>1.0 ± 0.3</td><td>GRASSLER</td><td>77</td><td>HBC 16 π<sup>+</sup> p</td></tr></tbody></table>

¹CORDEN 78 assumes low-mass $\eta\pi\pi$ region is dominantly $1^{++}$. See BARBERIS 98C and MANAK 00A for discussion.

²K$\bar{K}$ system characterized by the $l=1$ threshold enhancement. (See under $a_0(980)$).

$$ \Gamma(K\bar{K}^*(892))/\Gamma_{\text{total}} \qquad \Gamma_{12}/\Gamma $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>not seen</td><td>NACASCH</td><td>78</td><td>HBC 0.7,0.76 p̄p → K$\bar{K}$ 3π</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>not seen</td><td>NACASCH</td><td>78</td><td>HBC 0.7,0.76 p̄p → K$\bar{K}$ 3π</td></tr></tbody></table>

¹A clear signal of 19.8 ± 4.4 events observed at high $Q^2$.

$$ \Gamma(\pi^{+} \pi^{-} \pi^{0})/\Gamma_{\text{total}} \qquad \Gamma_{13}/\Gamma $$

<table><thead><tr><th>VALUE (%)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.30 ± 0.055 ± 0.074</td><td>2.3k</td><td>1 DOROFEEV</td><td>11</td><td>VES π<sup>-</sup> N → π<sup>-</sup> f<sub>1</sub>(1285) N</td></tr></tbody></table>

¹Value obtained selecting the region corresponding to $f_0(980)$ in the $\pi^+\pi^-$ mass spectrum. The systematic error includes the uncertainty on the partial width $f_1 \rightarrow \eta\pi\pi$ obtained from PDG 10 data.

$$ \Gamma(\rho^{+} \pi^{-})/\Gamma_{\text{total}} \qquad \Gamma_{14}/\Gamma $$

<table><thead><tr><th>VALUE (%)</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td><0.31</td><td>95</td><td>DOROFEEV</td><td>11</td><td>VES π<sup>-</sup> N → π<sup>-</sup> f<sub>1</sub>(1285) N</td></tr></tbody></table>

$$ \Gamma(\rho^{0})/\Gamma_{\text{total}} \qquad \Gamma_{15}/\Gamma $$

<table><thead><tr><th>VALUE (units 10<sup>-2</sup>)</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>6.1 ± 1.0 OUR FIT</td><td>Error includes scale factor of 1.7.</td><td></td><td></td><td></td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>2.8 ± 0.7 ± 0.6</td><td>1 AMELIN</td><td>95</td><td>VES 37 π<sup>-</sup> N → π<sup>-</sup> π<sup>+</sup> π<sup>-</sup> γN</td></tr><tr><td><5</td><td>BITYUKOV</td><td>91B</td><td>SPEC 32 π<sup>-</sup> p → π<sup>+</sup> π<sup>-</sup> γn</td></tr></tbody></table>

¹Not an independent measurement.

$$ \Gamma(\gamma\rho^{0})/\Gamma(2\pi^{+} 2\pi^{-}) \qquad \Gamma_{15}/\Gamma_{3} = \Gamma_{15}/\frac{1}{2}f_{1} $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.55 ± 0.10 OUR FIT</td><td>Error includes scale factor of 1.5.</td><td></td><td></td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.45 ± 0.18</td><td>1 COFFMAN</td><td>90</td><td>MRK3 J/ψ → γγπ<sup>+</sup> π<sup>-</sup></td></tr></tbody></table>

¹Using $B(J/ψ \rightarrow \gamma f_1(1285) \rightarrow \gamma\gamma\rho^0) = 0.25 \times 10^{-4}$ and $B(J/ψ \rightarrow \gamma f_1(1285) \rightarrow \gamma 2\pi^+ 2\pi^-) = 0.55 \times 10^{-4}$ given by MIR 88.

$$ \Gamma_8/\Gamma_{15} = (\Gamma_9+\Gamma_{10})/\Gamma_{15} $$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>8.6 ± 1.6 OUR FIT</td><td>Error includes scale factor of 1.9.</td><td></td><td></td></tr></tbody></table>

8.5 ± 2.0 OUR AVERAGE

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>21.3 ± 4.4</td><td>DICKSON</td><td>16</td><td>CLAS γp → f<sub>1</sub>(1285) p</td></tr><tr><td>10.0 ± 1.0 ± 2.0</td><td>BARBERIS</td><td>98C</td><td>OMEG 450 pp → ρf<sub>1</sub>(1285) p<sub>S</sub></td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>7.5 ± 1.0</td><td>1 ARMSTRONG</td><td>92c</td><td>OMEG 300 pp → ρpπ<sup>+</sup> π<sup>-</sup>γ, ρpηπ<sup>+</sup> π<sup>-</sup></td></tr></tbody></table>

¹Published value multiplied by 1.5.

<figure><img src="image_456.png" /></figure>

Values above of weighted average, error, and scale factor are based upon the data in this ideogram only. They are not necessarily the same as our 'best' values, obtained from a least-squares constrained fit utilizing measurements of other (related) quantities as additional information.

$$ \Gamma(\gamma\rho^{0})/\Gamma(K\bar{K}\pi) \qquad \Gamma_{15}/\Gamma_{11} $$

<table><thead><tr><th>VALUE</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>• • • We do not use the following data for averages, fits, limits, etc. • • •</td><td></td><td></td><td></td><td></td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>>0.035</td><td>90</td><td>1 COFFMAN</td><td>90</td><td>MRK3 J/ψ → γγπ<sup>+</sup> π<sup>-</sup></td></tr></tbody></table>

¹Using $B(J/ψ \rightarrow \gamma f_1(1285) \rightarrow \gamma\gamma\rho^0) = 0.25 \times 10^{-4}$ and $B(J/ψ \rightarrow \gamma f_1(1285) \rightarrow \gamma K\bar{K}\pi) = 0.72 \times 10^{-3}$.

$$ \Gamma(\phi\gamma)/\Gamma(K\bar{K}\pi) \qquad \Gamma_{16}/\Gamma_{11} $$

<table><thead><tr><th>VALUE (units 10<sup>-2</sup>)</th><th>CL%</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>0.82 ± 0.21 ± 0.20</td><td>19</td><td>BITYUKOV</td><td>88</td><td>SPEC 32.5 π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td><0.50</td><td>95</td><td>BARBERIS</td><td>98c</td><td>OMEG 450 pp → ρf<sub>1</sub>(1285) p<sub>S</sub></td></tr></tbody></table>

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td><0.93</td><td>95</td><td>AMELIN</td><td>95</td><td>VES 37 π<sup>-</sup> N → π<sup>+</sup> π<sup>+</sup> π<sup>-</sup> γN</td></tr></tbody></table>

$$ \Gamma(e^{+} e^{-})/\Gamma_{\text{total}} \qquad \Gamma_{17}/\Gamma $$

<table><thead><tr><th>VALUE</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td><9.4 × 10<sup>-9</sup></td><td>90</td><td>1 ACHASOV</td><td>20</td><td>SND e<sup>+</sup> e<sup>-</sup> → ηπ<sup>0</sup> π<sup>0</sup></td></tr></tbody></table>

¹AChASOV 20 reports two candidate events corresponding to a significance of 2.5 σ and the branching fraction of $(5.1^{+3.7}_{-2.7}) \times 10^{-9}$.

f₁(1285) REFERENCES

<table><thead><tr><th>NAME</th><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>ABLIKIM</td><td>23M</td><td>JHEP 2303 121</td><td>M. Ablikim et al.</td><td>(BESIII Collab.)</td></tr><tr><td>ACHASOV</td><td>20</td><td>PL B800 135074</td><td>M. N.A. Chasov et al.</td><td>(SND Collab.)</td></tr><tr><td>ABLIKIM</td><td>19BA</td><td>PR D100 092003</td><td>M. Ablikim et al.</td><td>(BESIII Collab.)</td></tr><tr><td>DICKSON</td><td>16</td><td>PR C93 065202</td><td>R. Dickson et al.</td><td>(JLab CLAS Collab.)</td></tr><tr><td>ABLIKIM</td><td>15P</td><td>PR D92 012007</td><td>M. Ablikim et al.</td><td>(BESIII Collab.)</td></tr><tr><td>AALI</td><td>14Y</td><td>PR P112 092012</td><td>R. Aalai et al.</td><td>(LHCb Collab.)</td></tr><tr><td>LEES</td><td>12X</td><td>PR D86 092010</td><td>J.P. Lees et al.</td><td>(BABAR Collab.)</td></tr><tr><td>ABLIKIM</td><td>11J</td><td>PR 107 182001</td><td>M. Ablikim et al.</td><td>(BESIII Collab.)</td></tr><tr><td>DOROFEEV</td><td>11</td><td>EPJ A47 68</td><td>V. Dorofeev et al.</td><td>(SERP, MIPT)</td></tr><tr><td>PDG</td><td>10</td><td>JP G37 075021</td><td>K. Nakamura et al.</td><td>(PDG Collab.)</td></tr><tr><td>ACHARD</td><td>07</td><td>JHEP 0703 018</td><td>P. Achar et al.</td><td>(L3 Collab.)</td></tr><tr><td>AUBERT</td><td>07AU</td><td>PR D76 092005</td><td>B. Aubert et al.</td><td>(BABAR Collab.)</td></tr><tr><td>BAI</td><td>04J</td><td>PL B594 47</td><td>J.Z. Bai et al.</td><td>(BES Collab.)</td></tr><tr><td>ABDALLAH</td><td>03H</td><td>PL B569 129</td><td>J. Abdallah et al.</td><td>(DELPHI Collab.)</td></tr><tr><td>ACHARD</td><td>02B</td><td>PL B526 269</td><td>P. Achar et al.</td><td>(L3 Collab.)</td></tr><tr><td>ACCIARRI</td><td>01G</td><td>PL B501 1</td><td>M. Acciarri et al.</td><td>(L3 Collab.)</td></tr><tr><td>ADAMS</td><td>01B</td><td>PL B516 254</td><td>G.S. Adams et al.</td><td>(BNL E852 Collab.)</td></tr><tr><td>BARBERIS</td><td>00C</td><td>PL B471 440</td><td>D. Barberis et al.</td><td>(WA 102 Collab.)</td></tr><tr><td>MANAK</td><td>00A</td><td>PR D62 012003</td><td>J.J. Manak et al.</td><td>(BNL E852 Collab.)</td></tr><tr><td>SOSA</td><td>99</td><td>PR L83 913</td><td>M. Sosa et al.</td><td>(WA 102 Collab.)</td></tr><tr><td>BARBERIS</td><td>98C</td><td>PL B440 225</td><td>D. Barberis et al.</td><td>(GAMS Collab.)</td></tr><tr><td>ALDE</td><td>97B</td><td>PAN 60 386</td><td>D. Alde et al.</td><td>(WA 102 Collab.)</td></tr><tr><td>BARBERIS</td><td>97B</td><td>PL B413 217</td><td>D. Barberis et al.</td><td>(WA 102 Collab.)</td></tr><tr><td>BARBERIS</td><td>97C</td><td>PL B413 225</td><td>D. Barberis et al.</td><td>(WA 102 Collab.)</td></tr><tr><td>AMELIN</td><td>95</td><td>ZPHY C66 71</td><td>D.V. Amelin et al.</td><td>(VES Collab.)</td></tr><tr><td>ANTINORI</td><td>95</td><td>PL B353 589</td><td>F. Antinori et al.</td><td>(ATHU, BARI, BIRM+)</td></tr><tr><td>ABATZIS</td><td>94</td><td>PL B324 509</td><td>S. Abatzis et al.</td><td>(ATHU, BARI, BIRM+)</td></tr><tr><td>LEE</td><td>94</td><td>PL B323 227</td><td>J.H. Lee et al.</td><td>(BNL, IND, KYUN, MASD+)</td></tr><tr><td>ARMSTRONG</td><td>93C</td><td>PL B307 394</td><td>T.A. Armstrong et al.</td><td>(FNAL, FERR, GENO+)</td></tr><tr><td>ARMSTRONG</td><td>92C</td><td>ZPHY C54 371</td><td>T. Armstrong et al.</td><td>(ATHU, BARI, BIRM+)</td></tr><tr><td>BOLTON</td><td>92</td><td>PL B278 495</td><td>T. Bolton et al.</td><td>(Mark III Collab.)</td></tr><tr><td>BITYUKOV</td><td>91B</td><td>SJNP 54 318</td><td>S.J. Bityukov et al.</td><td>(SERP)</td></tr></tbody></table>
# Meson Particle Listings

$f_1(1285)$, $\eta(1295)$, $\pi(1300)$

<table><tr><td>FUKUI</td><td>91C</td><td>PL B267 293</td></tr><tr><td>COFFMAN</td><td>90</td><td>PR D41 1410</td></tr><tr><td>ARMSTRONG</td><td>89</td><td>PL B221 216</td></tr><tr><td>ARMSTRONG</td><td>89E</td><td>PL B228 536</td></tr><tr><td>ARMSTRONG</td><td>89G</td><td>ZPHY C43 55</td></tr><tr><td>RATH</td><td>89</td><td>PR D40 693</td></tr><tr><td>AIHARA</td><td>88B</td><td>PL B209 107</td></tr><tr><td>BIRMAN</td><td>88</td><td>PRL 61 1557</td></tr><tr><td>BITYUKOV</td><td>88</td><td>PL B203 327</td></tr><tr><td>MIR</td><td>88</td><td>Photon-Photon 88, 126</td></tr></table>

Conference

<table><tr><td>ALDE</td><td>87</td><td>PL B198 286</td><td>D.M. Alde et al. (SUGL, NAGO, KEK, KYOT+)</td></tr><tr><td>BECKER</td><td>87</td><td>PRL 59 186</td><td>D.M. Coffman et al. (Mark III Collab.)</td></tr><tr><td>GIDAL</td><td>87</td><td>PRL 59 2012</td><td>T.A. Armstrong et al. (CERN, CDEF, BIRM+) JPC</td></tr><tr><td>ANDO</td><td>86</td><td>PRL 57 1296</td><td>T.A. Armstrong, M. Benayoun (ATHU, BARI, BIRM+)</td></tr><tr><td>REEVES</td><td>86</td><td>PR D34 1960</td><td>T.A. Armstrong et al. (CERN, BIRM, BARI+)</td></tr><tr><td>CHUNG</td><td>85</td><td>PRL 55 779</td><td>M.G. Rath et al. (NDAM, BRAN, BNL, CUNY+)</td></tr><tr><td>ARMSTRONG</td><td>84</td><td>PL 146B 273</td><td>H. Aihara et al. (TPC-2+ Collab.)</td></tr><tr><td>BITYUKOV</td><td>84B</td><td>PL 144B 133</td><td>A. Birman et al. (BNL, FSU, IND, MASD) JP</td></tr><tr><td>CHAUVAT</td><td>84</td><td>PL 148B 382</td><td>S.I. Bityukov et al. (SERP)</td></tr><tr><td>TORNQVIST</td><td>82B</td><td>NP B203 268</td><td>P. Chauvat et al. (CERN, CLER, UCLA+)</td></tr><tr><td>EVANGELIS...</td><td>81</td><td>NP B178 197</td><td>N.A. Tornqvist (HELS)</td></tr><tr><td>BROMBERG</td><td>80</td><td>PR D22 1513</td><td>C. Evangelista et al. (BARI, BONN, CERN+)</td></tr><tr><td>DIONISI</td><td>80</td><td>NP B169 1</td><td>C.M. Bromberg et al. (CIT, FNAL, ILLC+)</td></tr><tr><td>GURTU</td><td>79</td><td>NP B151 781</td><td>C. Dionisi et al. (CERN, MADR, CDEF+)</td></tr><tr><td>STANTON</td><td>79</td><td>PRL 42 346</td><td>A. Gurtu et al. (CERN, ZEEM, NIJM, OXF)</td></tr><tr><td>CORDEN</td><td>78</td><td>NP B144 253</td><td>N.R. Stanton et al. (OSU, CARL, MCGI+) JP</td></tr><tr><td>NACASCH</td><td>78</td><td>NP B135 203</td><td>M.J. Corden et al. (BIRM, RHEL, TELA+) JP</td></tr><tr><td>GRASSLER</td><td>77</td><td>NP B121 189</td><td>R. Nacasch et al. (PARIS, MADR, CERN+)</td></tr><tr><td>DEFOIX</td><td>72</td><td>NP B44 125</td><td>H. Grassler et al. (AACH, BERL, BONN+) JP</td></tr><tr><td>DUBOC</td><td>72</td><td>NP B46 429</td><td>C. Dofeix et al. (CDEF, CERN)</td></tr><tr><td>THUN</td><td>72</td><td>PRL 28 1733</td><td>J. Duboc et al. (PARIS, LIVP)</td></tr><tr><td>BARDADIN...</td><td>71</td><td>PR D4 2711</td><td>R. Thun et al. (STON, NEAS)</td></tr><tr><td>BOESEBECK</td><td>71</td><td>PR 34B 659</td><td>M. Bardadin-Otwinowska et al. (WARS)</td></tr><tr><td>CAMPBELL</td><td>69</td><td>PRL 22 1204</td><td>K. Boesebeck (AACH, BERL, BONN, CERN, CRAC+) JP</td></tr><tr><td>LORSTAD</td><td>69</td><td>NP B14 63</td><td>J.H. Campbell et al. (PURD)</td></tr><tr><td>D'ANDLAU</td><td>68</td><td>NP B5 693</td><td>B. Lorstad et al. (CDEF, CERN) JP</td></tr><tr><td>DAHL</td><td>67</td><td>PR 163 1377</td><td>C. d'Andlau et al. (CDEF, CERN, IRAD+) JP</td></tr></table>

$$\eta(1295)$$

$$I^G(JPC) = 0^+(0^- +)$$

See the review on "Spectroscopy of Light Meson Resonances."

## η(1295) MASS

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>1294 ± 4 OUR AVERAGE</strong></td></tr><tr><td>1302 ± 9</td><td>8</td><td>20k</td><td>ADAMS</td><td>01B B852 18 GeV π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>1282 ± 5</td><td>9082</td><td>MANAK</td><td>00A MPS</td><td>18 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td></tr><tr><td>1299 ± 4</td><td>2100</td><td>ALDE</td><td>97B GAM4 100 π<sup>-</sup> p → ηπ<sup>0</sup> π<sup>0</sup> n</td><td></td></tr><tr><td>1295 ± 4</td><td></td><td>FUKUI</td><td>91C SPEC 8.95 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td><td></td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><caption>WEIGHTED AVERAGE
1294±4 (Error scaled by 1.6)</caption><tr><td>1264 ± 8</td><td>1 AUGUSTIN</td><td>90 DM2 J/ψ → γηπ<sup>+</sup> π<sup>-</sup></td></tr><tr><td>~ 1275</td><td>STANTON</td><td>79 CNTR 8.4 π<sup>-</sup> p → nη2π</td></tr></table>

<figure><img src="image_457.png" /><figcaption>$\eta(1295)$ mass (MeV)</figcaption></figure>

1 PWA analysis of AUGUSTIN 92 assigns 0<sup>-+</sup> quantum numbers to this state rather than 1<sup>++</sup> as before.

## η(1295) WIDTH

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>55 ± 5 OUR AVERAGE</strong></td></tr><tr><td>57 ± 23</td><td>21</td><td>20k</td><td>ADAMS</td><td>01B B852 18 GeV π<sup>-</sup> p → K<sup>+</sup> K<sup>-</sup> π<sup>0</sup> n</td></tr><tr><td>66 ± 13</td><td>9082</td><td>MANAK</td><td>00A MPS</td><td>18 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td></tr><tr><td>53 ± 6</td><td></td><td>FUKUI</td><td>91C SPEC 8.95 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td><td></td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>&lt;40</td><td>2100</td><td>ALDE</td><td>97B GAM4 100 π<sup>-</sup> p → ηπ<sup>0</sup> π<sup>0</sup> n</td></tr><tr><td>44 ± 20</td><td></td><td>1 AUGUSTIN</td><td>90 DM2 J/ψ → γηπ<sup>+</sup> π<sup>-</sup></td></tr><tr><td>~ 70</td><td></td><td>STANTON</td><td>79 CNTR 8.4 π<sup>-</sup> p → nη2π</td></tr></table>

¹ PWA analysis of AUGUSTIN 92 assigns 0<sup>-+</sup> quantum numbers to this state rather than 1<sup>++</sup> as before.

## η(1295) DECAY MODES

<table><thead><tr><th>Mode</th><th>Fraction (Γ<sub>j</sub>/Γ)</th></tr></thead><tbody><tr><td>Γ<sub>1</sub></td><td>ηπ<sup>+</sup> π<sup>-</sup> seen</td></tr><tr><td>Γ<sub>2</sub></td><td>a<sub>0</sub>(980) π seen</td></tr><tr><td>Γ<sub>3</sub></td><td>γγ seen</td></tr><tr><td>Γ<sub>4</sub></td><td>ηπ<sup>0</sup> π<sup>0</sup> seen</td></tr><tr><td>Γ<sub>5</sub></td><td>η(ππ)s-wave seen</td></tr><tr><td>Γ<sub>6</sub></td><td>ση seen</td></tr><tr><td>Γ<sub>7</sub></td><td>KKπ seen</td></tr></tbody></table>

## η(1295) Γ(Γ(γγ)/Γ(total)

$$\begin{array}{l} \Gamma(\eta\pi^+\pi^-) \times \Gamma(\gamma\gamma)/\Gamma_{\text{total}} \\ \text{VALUE (keV)} \qquad \text{CL\%} \qquad \text{DOCUMENT ID} \qquad \text{TECN} \qquad \text{COMMENT} \\ <0.066 \qquad 95 \qquad \text{ACCIARRI} \qquad \text{01G} \qquad \text{L3} \qquad 183-202 e^+ e^- \rightarrow e^+ e^- \eta\pi^+ \pi^- \end{array}$$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>&lt;0.6</td><td>90</td><td>AIHARA</td><td>88C TPC</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>ηπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>&lt;0.3</td><td></td><td>ANTREASYAN</td><td>87 CBAL</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>ηππ</td></tr></table>

$$\begin{array}{l} \Gamma(K\bar{K}\pi) \times \Gamma(\gamma\gamma)/\Gamma_{\text{total}} \\ \text{VALUE (keV)} \qquad \text{CL\%} \qquad \text{DOCUMENT ID} \qquad \text{TECN} \qquad \text{COMMENT} \\ <0.014 \qquad 90 \qquad 1,2 AHOHE \qquad 05 CLE2 \qquad 10.6 e^+ e^- \rightarrow e^+ e^- K_5^0 K^\pm \pi^\mp \end{array}$$

¹ Using η(1295) mass and width 1294 MeV and 55 MeV, respectively.

² Assuming three-body phase-space decay to $K_5^0 K^\pm \pi^\mp$.

## η(1295) BRANCHING RATIOS

$$\begin{array}{l} \Gamma(\alpha_0(980)\pi)/\Gamma_{\text{total}} \\ \text{VALUE} \qquad \text{DOCUMENT ID} \qquad \text{TECN} \qquad \text{COMMENT} \\ \text{Γ}_2/\text{Γ}_4 \end{array}$$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>not seen</td><td>BERTIN</td><td>97</td><td>OBLX</td><td>0.0 p p → K<sup>±</sup> (K<sup>0</sup>) π<sup>∓</sup> π<sup>+</sup> π<sup>-</sup></td></tr><tr><td>seen</td><td>BIRMAN</td><td>88</td><td>MPS</td><td>8 π<sup>-</sup> p → K<sup>+</sup> K<sup>0</sup> π<sup>0</sup> n</td></tr><tr><td>large</td><td>ANDO</td><td>86</td><td>SPEC</td><td>8 π<sup>-</sup> p → ηπ<sup>+</sup> π<sup>-</sup> n</td></tr><tr><td>large</td><td>STANTON</td><td>79</td><td>CNTR</td><td>8.4 π<sup>-</sup> p → nη2π</td></tr></table>

$$\begin{array}{l} \Gamma(\alpha_0(980)\pi)/\Gamma(\eta\pi^0\pi^0) \\ \text{VALUE} \qquad \text{DOCUMENT ID} \qquad \text{TECN} \qquad \text{COMMENT} \\ 0.65 \pm 0.10 \qquad 1 \text{ ALDE} \qquad 97B GAM4 \qquad 100 \pi^- p \rightarrow \eta\pi^0\pi^0 n \end{array}$$

¹ Assuming that $a_0(980)$ decays only to $\eta\pi$.

$$\begin{array}{l} \Gamma(\eta(\pi\pi)s-wave)/\Gamma(\eta\pi^0\pi^0) \\ \text{VALUE} \qquad \text{DOCUMENT ID} \qquad \text{TECN} \qquad \text{COMMENT} \\ 0.35 \pm 0.10 \qquad ALDE \qquad 97B GAM4 \qquad 100 \pi^- p \rightarrow \eta\pi^0\pi^0 n \end{array}$$

$$\begin{array}{l} \Gamma(\alpha_0(980)\pi)/\Gamma(\sigma\eta) \\ \text{VALUE} \qquad \text{DOCUMENT ID} \qquad \text{TECN} \qquad \text{COMMENT} \\ 0.48 \pm 0.22 \qquad 9082 \qquad MANAK \qquad 00A MPS \qquad 18 \pi^- p \rightarrow \eta\pi^+\pi^- n \end{array}$$

## η(1295) REFERENCES

<table><tr><td>AHOHE</td><td>05 PR D71 072001</td><td>R. Ahohe et al.</td><td>(CLEO Collab.)</td></tr><tr><td>ACCIARRI</td><td>01G PL B501 1</td><td>M. Acciarri et al.</td><td>(L3 Collab.)</td></tr><tr><td>ADAMS</td><td>01B PL B516 264</td><td>G.S. Adams et al.</td><td>(BNL E852 Collab.)</td></tr><tr><td>MANAK</td><td>00A PR D62 012003</td><td>J.J. Manak et al.</td><td>(BNL E852 Collab.)</td></tr><tr><td>ALDE</td><td>97B PAN 60 386</td><td>D. Alde et al.</td><td>(GAMS Collab.)</td></tr><tr><td>BERTIN</td><td>97 PL B400 226</td><td>Translated from YAF 60 458.</td><td>(OBELIX Collab.)</td></tr><tr><td>AUGUSTIN</td><td>92 PR D46 1951</td><td>J.E. Augustin, G. Cosme</td><td>(DM2 Collab.)</td></tr><tr><td>FUKUI</td><td>91C PL B267 293</td><td>S. Fukui et al.</td><td>(SUGL, NAGO, KEK, KYOT+)</td></tr><tr><td>AUGUSTIN</td><td>90 PR D42 10</td><td>J.E. Augustin et al.</td><td>(DM2 Collab.)</td></tr><tr><td>AIHARA</td><td>88C PR D38 1</td><td>H. Aihara et al.</td><td>(TPC-γ Collab.)</td></tr><tr><td>BIRMAN</td><td>88 PRL 61 1557</td><td>A. Birman et al.</td><td>(BNL, FSU, IND, MASD) JP</td></tr><tr><td>ANTREASYAN</td><td>87 PR D36 2633</td><td>D. Antreasyan et al.</td><td>(Crystal Ball Collab.)</td></tr><tr><td>ANDO</td><td>86 PRL 57 1296</td><td>A. A. Ando et al.</td><td>(KEK, KYOT, NIRS, SAGA+) UP</td></tr><tr><td>STANTON</td><td>79 PRL 42 346</td><td>N.R. Stanton et al.</td><td>(OSU, CARL, MCGI+) JP</td></tr></table>

$$\pi(1300)$$

$$I^G(JPC) = 1^-(0^+ +)$$

## π(1300) MASS

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>1300 ± 100 OUR ESTIMATE</strong></td></tr><tr><td>1128 ± 26</td><td>70</td><td>DARGENT</td><td>17 RVUE</td><td>D<sup>0</sup> → π<sup>-</sup> π<sup>+</sup> π<sup>-</sup> π<sup>+</sup></td></tr><tr><td>1345 ± 8</td><td>10</td><td>1 SCHEGELSKY</td><td>06 RVUE</td><td>γγ → π<sup>+</sup> π<sup>-</sup> π<sup>0</sup></td></tr></tbody></table>
See key on page 1171

Meson Particle Listings

$\pi(1300)$, $a_2(1320)$

<table><tbody><tr><td>1200 ± 40</td><td>90k</td><td>SALVINI</td><td>04</td><td>OBLX</td><td>p̄p → 2π<sup>+</sup>2π<sup>-</sup></td></tr><tr><td>1343 ± 15 ± 24</td><td></td><td>CHUNG</td><td>02</td><td>B852</td><td>18.3 π<sup>-</sup>p → π<sup>+</sup>π<sup>-</sup>π<sup>-</sup>p</td></tr><tr><td>1375 ± 40</td><td></td><td>ABELE</td><td>01</td><td>CBAR</td><td>0.0 p̄d → π<sup>-</sup>4π<sup>0</sup>p</td></tr><tr><td>1275 ± 15</td><td></td><td>BERTIN</td><td>97D</td><td>OBLX</td><td>0.05 p̄p → 2π<sup>+</sup>2π<sup>-</sup></td></tr><tr><td>~ 1114</td><td></td><td>ABELE</td><td>96</td><td>CBAR</td><td>0.0 p̄p → 5π<sup>0</sup></td></tr><tr><td>1190 ± 30</td><td></td><td>ZIELINSKI</td><td>84</td><td>SPEC</td><td>200 π<sup>+</sup>Z → Z3π</td></tr><tr><td>1240 ± 30</td><td></td><td>BELLINI</td><td>82</td><td>SPEC</td><td>40 π<sup>-</sup>A → A3π</td></tr><tr><td>1273 ± 50</td><td></td><td>2 AARON</td><td>81</td><td>RVUE</td><td></td></tr><tr><td>1342 ± 20</td><td></td><td>BONESINI</td><td>81</td><td>OMEG</td><td>12 π<sup>-</sup>p → p3π</td></tr><tr><td>~ 1400</td><td></td><td>DAUM</td><td>81B</td><td>SPEC</td><td>63,94 π<sup>-</sup>p</td></tr></tbody></table>

¹ From analysis of L3 data at 183–209 GeV.

² Uses multichannel Aitchison-Bowler model (BOWLER 75). Uses data from DAUM 80 and DANKOWYCH 81.

π(1300) WIDTH

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5"><strong>200 to 600 OUR ESTIMATE</strong></td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>314 ± 39 ± 66</td><td></td><td>DARGENT</td><td>17</td><td>RVUE</td><td>D<sup>0</sup> → π<sup>-</sup>π<sup>+</sup>π<sup>-</sup>π<sup>+</sup></td></tr><tr><td>260 ± 20 ± 30</td><td>18k</td><td>3 SCHEGELSKY</td><td>06</td><td>RVUE</td><td>γγ → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>470 ± 120</td><td>90k</td><td>SALVINI</td><td>04</td><td>OBLX</td><td>p̄p → 2π<sup>+</sup>2π<sup>-</sup></td></tr><tr><td>449 ± 39 ± 47</td><td></td><td>CHUNG</td><td>02</td><td>B852</td><td>18.3 π<sup>-</sup>p → π<sup>+</sup>π<sup>-</sup>π<sup>-</sup>p</td></tr><tr><td>268 ± 50</td><td></td><td>ABELE</td><td>01</td><td>CBAR</td><td>0.0 p̄d → π<sup>-</sup>4π<sup>0</sup>p</td></tr><tr><td>218 ± 100</td><td></td><td>BERTIN</td><td>97D</td><td>OBLX</td><td>0.05 p̄p → 2π<sup>+</sup>2π<sup>-</sup></td></tr><tr><td>~ 340</td><td></td><td>ABELE</td><td>96</td><td>CBAR</td><td>0.0 p̄p → 5π<sup>0</sup></td></tr><tr><td>440 ± 80</td><td></td><td>ZIELINSKI</td><td>84</td><td>SPEC</td><td>200 π<sup>+</sup>Z → Z3π</td></tr><tr><td>360 ± 120</td><td></td><td>BELLINI</td><td>82</td><td>SPEC</td><td>40 π<sup>-</sup>A → A3π</td></tr><tr><td>580 ± 100</td><td></td><td>4 AARON</td><td>81</td><td>RVUE</td><td></td></tr><tr><td>220 ± 70</td><td></td><td>BONESINI</td><td>81</td><td>OMEG</td><td>12 π<sup>-</sup>p → p3π</td></tr><tr><td>~ 600</td><td></td><td>DAUM</td><td>81B</td><td>SPEC</td><td>63,94 π<sup>-</sup>p</td></tr></tbody></table>

³ From analysis of L3 data at 183–209 GeV.

⁴ Uses multichannel Aitchison-Bowler model (BOWLER 75). Uses data from DAUM 80 and DANKOWYCH 81.

π(1300) DECAY MODES

<table><thead><tr><th>Mode</th><th>Fraction (Γ<sub>i</sub>/Γ)</th></tr></thead><tbody><tr><td>Γ<sub>1</sub> ππ</td><td>seen</td></tr><tr><td>Γ<sub>2</sub> π(ππ)S-wave</td><td>seen</td></tr><tr><td>Γ<sub>3</sub> γγ</td><td></td></tr></tbody></table>

π(1300) Γ(γγ)/Γ(total)

<table><thead><tr><th>Γ(ρπ) × Γ(γγ)/Γ<sub>total</sub></th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>VALUE (keV)</td><td></td><td></td><td></td><td></td></tr><tr><td><0.085</td><td>90</td><td>ACCIARRI</td><td>97T</td><td>L3</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>&lt;0.8</td><td>95</td><td>5 SCHEGELSKY</td><td>06</td><td>RVUE</td><td>γγ → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>&lt;0.54</td><td>90</td><td>ALBRECHT</td><td>97B</td><td>ARG</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr></tbody></table>

⁵ From analysis of L3 data at 183–209 GeV.

π(1300) BRANCHING RATIOS

<table><thead><tr><th>Γ(π(ππ)S-wave)/Γ(ρπ)</th><th>CL%</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="6"><strong>Γ<sub>2</sub>/Γ<sub>1</sub></strong></td></tr><tr><td>• • • We do not use the following data for averages, fits, limits, etc. • • •</td><td></td><td></td><td></td><td></td><td></td></tr></tbody></table>

<table><tbody><tr><td>2.2 ± 0.4</td><td>90k</td><td>SALVINI</td><td>04</td><td>OBLX</td><td>p̄p → 2π<sup>+</sup>2π<sup>-</sup></td></tr><tr><td>seen</td><td></td><td>CHUNG</td><td>02</td><td>B852</td><td>18.3 π<sup>-</sup>p → π<sup>+</sup>2π<sup>-</sup>p</td></tr><tr><td>&lt;0.15</td><td>90</td><td>ABELE</td><td>01</td><td>CBAR</td><td>0.0 p̄d → π<sup>-</sup>4π<sup>0</sup>p</td></tr><tr><td>2.12</td><td></td><td>6 AARON</td><td></td><td>RVUE</td><td></td></tr></tbody></table>

⁶ Uses multichannel Aitchison-Bowler model (BOWLER 75). Uses data from DAUM 80 and DANKOWYCH 81.

π(1300) REFERENCES

<table><tbody><tr><td>DARGENT</td><td>17</td><td>JHEP 1705 143</td><td>P. dArgent et al.</td><td>(HEID, BRIS)</td></tr><tr><td>SCHEGELSKY</td><td>06</td><td>EPJ A27 199</td><td>V.A. Schegelsky et al.</td><td></td></tr><tr><td>SALVINI</td><td>04</td><td>EPJ C35 21</td><td>P. Salvini et al.</td><td>(OBELIX, Collab.)</td></tr><tr><td>CHUNG</td><td>02</td><td>PR D65 072001</td><td>S.U. Chung et al.</td><td>(BNL E852 Collab.)</td></tr><tr><td>ABELE</td><td>01</td><td>EPJ C19 667</td><td>A. Abele et al.</td><td>(Crystal Barrel Collab.)</td></tr><tr><td>ACCIARRI</td><td>97T</td><td>PL B413 147</td><td>M. Acciarri et al.</td><td>(L3 Collab.)</td></tr><tr><td>ALBRECHT</td><td>97B</td><td>ZPHY C74 469</td><td>H. Albrecht et al.</td><td>(ARGUS Collab.)</td></tr><tr><td>BERTIN</td><td>97D</td><td>PL B414 220</td><td>A. Bertin et al.</td><td>(OBELIX Collab.)</td></tr><tr><td>ABELE</td><td>96</td><td>PL B380 453</td><td>A. Abele et al.</td><td>(Crystal Barrel Collab.)</td></tr><tr><td>ZIELINSKI</td><td>84</td><td>PR D30 1855</td><td>M. Zielinski et al.</td><td>(ROCH, MINN, FNAL)</td></tr><tr><td>BELLINI</td><td>82</td><td>PRL 48 1697</td><td>G. Bellini et al.</td><td>(MILA, BGNA, JINR)</td></tr><tr><td>AARON</td><td>81</td><td>PRL D24 1207</td><td>R.A. Aaron, R.S. Longacre</td><td>(NEAS, BNL)</td></tr><tr><td>BONESINI</td><td>81</td><td>PL 103B 75</td><td>M. Bonesini et al.</td><td>(MILA, LIVP, DARE+)</td></tr><tr><td>DANKOWYCH...</td><td>81</td><td>PRL 46 580</td><td>J.A. Dankowych et al.</td><td>(TNTO, BNL, CARL+)</td></tr><tr><td>DAUM</td><td>81B</td><td>NP B182 269</td><td>C. Daum et al.</td><td>(AMST, CERN, CRAC, MPIM+)</td></tr><tr><td>DAUM</td><td>80</td><td>PL 89B 281</td><td>C. Daum et al.</td><td>(AMST, CERN, CRAC, MPIM+)</td></tr><tr><td>BOWLER</td><td>75</td><td>NP BP 277</td><td>M.G. Bowler et al.</td><td>(OXFTP, DARE)</td></tr></tbody></table>

a₂(1320)

$$I^G(J^{PC}) = 1^{-(2^{++})}$$

a₂(1320) T-MATRIX POLE $\sqrt{s}$

Note that $\Gamma = -2 \operatorname{Im}(\sqrt{s})$.

<table><thead><tr><th>VALUE (MeV)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="4">(1305-1321)-i(52-58) OUR ESTIMATE</td></tr><tr><td>(1318.7 ± 1.9 ± 1.3)-i(53.8 ± 2.3<sup>+</sup>1.7<sup>-</sup>0.9)</td><td>1 KOPF</td><td>21</td><td>RVUE</td></tr><tr><td>(1312.5 ± 0.7 ± 2.6)-i(53.5 ± 0.6 ± 1.9)</td><td>2 ALBRECHT</td><td>20</td><td>RVUE</td></tr><tr><td>(1306.0 ± 0.8 ± 1.3)-i(57.2 ± 0.8 ± 0.0)</td><td>3 RODAS</td><td>19</td><td>RVUE</td></tr><tr><td>(1309 ± 4) - i (55 ± 2)</td><td>4 ANISOVICH</td><td>09</td><td>RVUE</td></tr></tbody></table>

¹ Extraction based on a combined fit of Crystal Barrel and $\pi\pi$ scattering data (ALBRECHT 20), and COMPASS data (ADOLPH 15), using a coupled-channel model of $\eta\pi, \eta'\pi$ and $K\bar{K}$ systems.

² T-matrix pole with 2 poles, 2 channels ($\pi^0\eta$ and $K\bar{K}$).

³ Coupled-channel analysis of both the $\eta\pi$ and $\eta'\pi$ systems using ADOLPH 15 data. Supersedes JACKURA 18. Performed by JPAC.

⁴ Amplitude did not include dispersive corrections. From analysis of $\eta\pi$ mode.

a₂(1320) MASS

<table><thead><tr><th>VALUE (MeV)</th><th>DOCUMENT ID</th><th>TECN</th><th>CHG</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5">1318.2 ± 0.6 OUR AVERAGE</td></tr><tr><td colspan="5">Includes data from the 4 datablocks that follow this one. Error includes scale factor of 1.2.</td></tr></tbody></table>

3π MODE

<table><thead><tr><th>VALUE (MeV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>CHG</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="6">The data in this block is included in the average printed for a previous datablock.</td></tr></tbody></table>

1318.6 ± 1.3 OUR AVERAGE

<table><tbody><tr><td>1314.5<sup>+</sup> 4.0<sup>-</sup> 3.3</td><td>46M</td><td>1 AGHASYAN</td><td>18B</td><td>COMP</td><td>190 π<sup>-</sup>p → π<sup>-</sup>π<sup>+</sup>π<sup>-</sup>p</td></tr><tr><td>1326 ± 2 ± 2</td><td></td><td>CHUNG</td><td>02</td><td>B852</td><td>18.3 π<sup>-</sup>p → π<sup>+</sup>π<sup>-</sup>π<sup>-</sup>p</td></tr><tr><td>1317 ± 3</td><td></td><td>BARBERIS</td><td>98B</td><td></td><td>450 pp → pFπ<sup>+</sup>π<sup>-</sup>π<sup>0</sup>p<sub>S</sub></td></tr><tr><td>1323 ± 4 ± 3</td><td></td><td>ACCIARRI</td><td>97T</td><td>L3</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>1320 ± 7</td><td></td><td>ALBRECHT</td><td>97B</td><td>ARG</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>1311.3 ± 1.6 ± 3.0</td><td>72.4k</td><td>AMELIN</td><td>96</td><td>VES</td><td>36 π<sup>-</sup>p → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup>n</td></tr><tr><td>1310 ± 5</td><td></td><td>ARMSTRONG</td><td>90</td><td>OMEG</td><td>300.0p → pFπ<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>1323.8 ± 2.3</td><td>4022</td><td>AUGUSTIN</td><td>89</td><td>DM2</td><td>J/ψ → p<sup>0</sup>a<sup>±</sup></td></tr><tr><td>1320.6 ± 3.1</td><td>3562</td><td>AUGUSTIN</td><td>89</td><td>DM2</td><td>J/ψ → p<sup>0</sup>a<sup>0</sup></td></tr><tr><td>1317 ± 2</td><td>25k</td><td>2 DAUM</td><td>80c</td><td>SPEC</td><td>63.94 π<sup>-</sup>p → 3πp</td></tr><tr><td>1320 ± 10</td><td>1097</td><td>2 BALTAY</td><td>78b</td><td>HBC</td><td>15 π<sup>+</sup>p → p4π</td></tr><tr><td>1306 ± 8</td><td></td><td>FERRERSORIA</td><td>78</td><td>ARG</td><td>9 π<sup>-</sup>p → p3π</td></tr><tr><td>1318 ± 7</td><td>1.6k</td><td>2 EMMS</td><td>75</td><td>DBC</td><td>4 π<sup>+</sup>n → p(3π)<sup>0</sup></td></tr><tr><td>1315 ± 5</td><td></td><td>2 ANTIPOV</td><td>73c</td><td>CNTR</td><td>25,40 π<sup>-</sup>p → pηπ<sup>-</sup></td></tr><tr><td>1306 ± 9</td><td>1580</td><td>CHALOUPKA</td><td>73</td><td>HBC</td><td>3.9 π<sup>-</sup>p</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>1321 ± 1<sup>+0</sup><sub>-7</sub></td><td>420k</td><td>3 ALEKSEEV</td><td>10</td><td>COMP</td><td>190 π<sup>-</sup>p̄b → π<sup>-</sup>π<sup>-</sup>π<sup>+</sup>p̄b'</td></tr><tr><td>1300 ± 2 ± 4</td><td>18k</td><td>4 SCHEGELSKY</td><td>06</td><td>RVUE</td><td>γγ → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>1305 ± 14</td><td></td><td>CONDO</td><td>93</td><td>SHF</td><td>γp → nπ<sup>+</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1310 ± 2</td><td></td><td>2 EVANGELIS...</td><td>81</td><td>OMEG</td><td>12 π<sup>-</sup>p → 3πp</td></tr><tr><td>1343 ± 11</td><td>490</td><td>BALTAY</td><td>78b</td><td>HBC</td><td>15 π<sup>+</sup>p → Δ3π</td></tr><tr><td>1309 ± 5</td><td>5k</td><td>BINNIE</td><td>71</td><td>MMS</td><td>π<sup>-</sup>p near a₂ threshold</td></tr><tr><td>1299 ± 6</td><td>28k</td><td>BOWEN</td><td>71</td><td>MMS</td><td>5 π<sup>-</sup>p</td></tr><tr><td>1300 ± 6</td><td>24k</td><td>BOWEN</td><td>71</td><td>MMS</td><td>5 π<sup>+</sup>p</td></tr><tr><td>1309 ± 4</td><td>17k</td><td>BOWEN</td><td>71</td><td>MMS</td><td>7 π<sup>-</sup>p</td></tr><tr><td>1306 ± 4</td><td>941</td><td>ALSTON...</td><td>70</td><td>HBC</td><td>7.0 π<sup>+</sup>p → 3πp</td></tr></tbody></table>

¹ Statistical error negligible.

² From a fit to $J^P = 2^+ \rho\pi$ partial wave.

³ Superseded by AGHASYAN 2018B.

⁴ From analysis of L3 data at 183–209 GeV.
WEIGHTED AVERAGE
1318.6±1.3 (Error scaled by 1.4)

<figure><img src="image_458.png" /></figure>

K̄ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT

The data in this block is included in the average printed for a previous datablock.

1318.1 ± 0.7 OUR AVERAGE

<table><tr><td>1319 ± 5</td><td>4700</td><td>1,2 CLELAND</td><td>82B SPEC +</td><td>50 π<sup>+</sup> p → K<sup>0</sup><sub>S</sub> K<sup>+</sup> p</td></tr><tr><td>1324 ± 6</td><td>5200</td><td>1,2 CLELAND</td><td>82B SPEC -</td><td>50 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub> K<sup>-</sup> p</td></tr><tr><td>1320 ± 2</td><td>4000</td><td>CHABAUD</td><td>80 SPEC -</td><td>17 π<sup>-</sup> A → K<sup>0</sup><sub>S</sub> K<sup>-</sup> A</td></tr><tr><td>1312 ± 4</td><td>11000</td><td>CHABAUD</td><td>78 SPEC -</td><td>9.8 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr><tr><td>1316 ± 2</td><td>4730</td><td>CHABAUD</td><td>78 SPEC -</td><td>18.8 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr><tr><td>1318 ± 1</td><td>1,3 MARTIN</td><td>MARGULIE</td><td>76 SPEC -</td><td>10 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub> K<sup>-</sup> p</td></tr><tr><td>1320 ± 2</td><td>2724</td><td>MARGULIE</td><td>76 SPEC -</td><td>23 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr><tr><td>1313 ± 4</td><td>730</td><td>FOLEY</td><td>72 CNTR</td><td>20.3 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr><tr><td>1319 ± 3</td><td>1500</td><td>3 GRAVER</td><td>71 ASPK -</td><td>17.2 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>1304 ±10</td><td>870</td><td>4 SCHEGELSKY 06A</td><td>RVUE 0</td><td>γγ → K<sup>0</sup><sub>S</sub> K<sup>0</sup><sub>S</sub></td></tr><tr><td>1330 ±11</td><td>1000</td><td>1,2 CLELAND</td><td>82B SPEC +</td><td>30 π<sup>+</sup> p → K<sup>0</sup><sub>S</sub> K<sup>+</sup> p</td></tr><tr><td>1324 ± 5</td><td>350</td><td>HYAMS</td><td>78 ASPK +</td><td>12.7 π<sup>+</sup> p → K<sup>+</sup> K<sup>0</sup><sub>S</sub> p</td></tr></table>

¹ From a fit to $J^P = 2^+ \text{ partial wave.}$

² Number of events evaluated by us.

³ Systematic error in mass scale subtracted.

⁴ From analysis of L3 data at 91 and 183–209 GeV.

ηπ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT

The data in this block is included in the average printed for a previous datablock.

1317.7 ± 1.4 OUR AVERAGE

<table><tr><td>1308 ± 9</td><td>BARBERIS</td><td>00H</td><td>450 pp →</td><td>p<sub>f</sub> π<sub>f</sub> π<sub>0</sub> p<sub>S</sub></td></tr><tr><td>1316 ± 9</td><td>BARBERIS</td><td>00H</td><td>450 pp →</td><td>Δ<sup>+</sup><sub>f</sub> π<sub>0</sub> p<sub>S</sub></td></tr><tr><td>1317 ± 1 ±2</td><td>THOMPSON</td><td>97 MPS</td><td>18 π<sup>-</sup> p → ηπ<sup>-</sup> p</td><td></td></tr><tr><td>1315 ± 5 ±2</td><td>1 AMSLER</td><td>94D CBAR</td><td>0.0 p<sub>f</sub> → π<sub>0</sub> π<sub>0</sub> η</td><td></td></tr><tr><td>1325.1 ± 5.1</td><td>AOYAGI</td><td>93 BKEI</td><td>π<sup>-</sup> p → ηπ<sup>-</sup> p</td><td></td></tr><tr><td>1317.7 ± 1.4 ±2.0</td><td>BELADIDZE</td><td>93 VES</td><td>37 π<sup>-</sup> N → ηπ<sup>-</sup> N</td><td></td></tr><tr><td>1323 ± 8</td><td>1000</td><td>2 KEY</td><td>73 OSPK -</td><td>6 π<sup>-</sup> p → pπ<sup>-</sup> η</td></tr></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>1307 ± 1 ±6</td><td>3 JACKURA</td><td>18 RVUE</td><td>π<sup>-</sup> p → ηπ<sup>-</sup> p</td><td></td></tr><tr><td>1315 ±12</td><td>4 ADOLPH</td><td>15 COMP</td><td>191 π<sup>-</sup> p → η<sup>(l)</sup> π<sup>-</sup> p</td><td></td></tr><tr><td>1324 ± 5</td><td>ARMSTRONG</td><td>93C E760 0</td><td>p<sub>f</sub> p → π<sup>0</sup> ηη → 6γ</td><td></td></tr><tr><td>1336.2 ± 1.7</td><td>DELFOSSE</td><td>81 SPEC +</td><td>π<sup>±</sup> p → pπ<sup>±</sup> η</td><td></td></tr><tr><td>1330.7 ± 2.4</td><td>DELFOSSE</td><td>81 SPEC -</td><td>π<sup>±</sup> p → pπ<sup>±</sup> η</td><td></td></tr><tr><td>1324 ± 8</td><td>6200</td><td>2,5 CONFORTO</td><td>73 OSPK -</td><td>6 π<sup>-</sup> p → pMM<sup>-</sup></td></tr></table>

¹ The systematic error of 2 MeV corresponds to the spread of solutions.

² Error includes 5 MeV systematic mass-scale error.

³ Superseded by RODAS 19.

⁴ ADOLPH 15 value is derived from a Breit-Wigner fit with mass-dependent width taking the ηπ and ρπ channels into account.

⁵ Missing mass with enriched MMS = ηπ⁻, η = 2γ.

η'π MODE

VALUE (MeV) DOCUMENT ID TECN COMMENT

The data in this block is included in the average printed for a previous datablock.

1322 ± 7 OUR AVERAGE

<table><tr><td>1318 ± 8</td><td>+3/5</td><td>IVANOV</td><td>01 B852</td><td>18 π<sup>-</sup> p → η'<sup>-</sup> π<sup>-</sup> p</td></tr><tr><td>1327.0 ±10.7</td><td></td><td>BELADIDZE</td><td>93 VES</td><td>37 π<sup>-</sup> N → η'<sup>-</sup> π<sup>-</sup> N</td></tr></table>

$a_2(1320)$ WIDTH

VALUE (MeV) DOCUMENT ID

107 ±5 OUR ESTIMATE

107.8 ±1.2 OUR AVERAGE Includes data from the 4 datablocks that follow this one.

3π MODE

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT

The data in this block is included in the average printed for a previous datablock.

105.0 ± 1.7 1.9 OUR AVERAGE

<table><tr><td>106.6 ± 3.4</td><td>46M</td><td>1 AGHASYAN</td><td>18B COMP</td><td>190 π<sup>-</sup> p → π<sup>-</sup> π<sup>+</sup> π<sup>-</sup> p</td></tr><tr><td>108 ± 3 ±15</td><td></td><td>CHUNG</td><td>02 B852</td><td>18.3 π<sup>-</sup> p → π<sup>+</sup> π<sup>-</sup> π<sup>-</sup> p</td></tr><tr><td>120 ±10</td><td></td><td>BARBERIS</td><td>98B</td><td>450 pp → p<sub>f</sub> π<sup>+</sup> π<sup>-</sup> π<sub>0</sub> p<sub>S</sub></td></tr><tr><td>105 ±10 ±11</td><td></td><td>ACCIARRI</td><td>97T L3</td><td>e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> π<sup>+</sup> π<sup>-</sup> π<sub>0</sub> 0</td></tr><tr><td>120 ±10</td><td></td><td>ALBRECHT</td><td>97B ARG</td><td>e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup> π<sup>+</sup> π<sup>-</sup> π<sub>0</sub> 0</td></tr><tr><td>103.0 ± 6.0 ± 3.3</td><td>72.4k</td><td>AMELIN</td><td>96 VES</td><td>36 π<sup>-</sup> p → π<sup>+</sup> π<sup>+</sup> π<sub>0</sub> π</td></tr><tr><td>120 ±10</td><td></td><td>ARMSTRONG</td><td>90 OMEG 0</td><td>300.0p → ppπ<sup>+</sup> π<sup>-</sup> π<sub>0</sub></td></tr><tr><td>107.0 ± 9.7</td><td>4022</td><td>AUGUSTIN</td><td>89 DM2 ±</td><td>J/ψ → p<sup>0</sup> a<sup>±</sup></td></tr><tr><td>118.5 ±12.5</td><td>3562</td><td>AUGUSTIN</td><td>89 DM2 0</td><td>J/ψ → p<sup>0</sup> a<sup>0</sup></td></tr><tr><td>97 ± 5</td><td></td><td>2 EVANGELIS...</td><td>81 OMEG -</td><td>12 π<sup>-</sup> p → 3πp</td></tr><tr><td>96 ± 9</td><td>25k</td><td>2 DAUM</td><td>80C SPEC -</td><td>63.94 π<sup>-</sup> p → 3πp</td></tr><tr><td>110 ±15</td><td>1097</td><td>2 BALTAY</td><td>78B HBC +0</td><td>15 π<sup>+</sup> p → p4π</td></tr><tr><td>112 ±18</td><td>1.6k</td><td>2 EMMIS</td><td>75 DBC 0</td><td>4 π<sup>+</sup> n → p(3π)<sup>0</sup></td></tr><tr><td>122 ±14</td><td>1.2k</td><td>2,3 WAGNER</td><td>75 HBC 0</td><td>7 π<sup>+</sup> p → Δ<sup>+</sup>(3π)<sup>0</sup></td></tr><tr><td>115 ±15</td><td></td><td>2 ANTIPOV</td><td>73c CNTR -</td><td>25,40 π<sup>-</sup> p → pηπ<sup>-</sup></td></tr><tr><td>99 ±15</td><td>1580</td><td>CHALOUPKA</td><td>73 HBC</td><td>3.9 π<sup>-</sup> p</td></tr><tr><td>105 ± 5</td><td>28k</td><td>BOWEN</td><td>71 MMS -</td><td>5 π<sup>-</sup> p</td></tr><tr><td>99 ± 5</td><td>24k</td><td>BOWEN</td><td>71 MMS +</td><td>5 π<sup>+</sup> p</td></tr><tr><td>103 ± 5</td><td>17k</td><td>BOWEN</td><td>71 MMS -</td><td>7 π<sup>-</sup> p</td></tr></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>110 ± 2 ±15</td><td>420k</td><td>4 ALEKSEEV</td><td>10 COMP</td><td>190 π<sup>-</sup> Pb → π<sup>-</sup> π<sup>+</sup> π<sup>+</sup> Pb<sup>+</sup></td></tr><tr><td>117 ± 6 ±20</td><td>18k</td><td>5 SCHEGELSKY</td><td>06 RVUE 0</td><td>γγ → π<sup>+</sup> π<sup>+</sup> π<sub>0</sub> 0</td></tr><tr><td>120 ±40</td><td></td><td>CONDO</td><td>93 SHF</td><td>γp → nπ<sup>+</sup> π<sup>+</sup> π<sup>-</sup></td></tr><tr><td>115 ±14</td><td>490</td><td>BALTAY</td><td>78b HBC 0</td><td>15 π<sup>+</sup> p → Δ3π</td></tr><tr><td>72 ±16</td><td>5k</td><td>BINNIE</td><td>71 MMS -</td><td>π<sup>-</sup> p near a<sub>2</sub> threshold</td></tr><tr><td>79 ±12</td><td>941</td><td>ALSTON...</td><td>70 HBC +</td><td>7.0 π<sup>+</sup> p → 3πp</td></tr></table>

¹ Statistical error negligible.

² From a fit to $J^P = 2^+ \rho\pi$ partial wave.

³ Width errors enlarged by us to $4\Gamma/\sqrt{N}$; see the note with the $K^*(892)$ mass.

⁴ Superseded by AGHASYAN 2018B.

⁵ From analysis of L3 data at 183–209 GeV.

K̄ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT

The data in this block is included in the average printed for a previous datablock.

109.8 ± 2.4 OUR AVERAGE

<table><tr><td>112 ±20</td><td>4700</td><td>1,2 CLELAND</td><td>82B SPEC +</td><td>50 π<sup>+</sup> p → K<sup>0</sup><sub>S</sub> K<sup>+</sup> p</td></tr><tr><td>120 ±25</td><td>5200</td><td>1,2 CLELAND</td><td>82B SPEC -</td><td>50 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub> K<sup>-</sup> p</td></tr><tr><td>106 ± 4</td><td>4000</td><td>CHABAUD</td><td>80 SPEC -</td><td>17 π<sup>-</sup> A → K<sup>0</sup><sub>S</sub> K<sup>-</sup> A</td></tr><tr><td>126 ±11</td><td>11000</td><td>CHABAUD</td><td>78 SPEC -</td><td>9.8 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub> K<sup>0</sup> p</td></tr><tr><td>101 ± 8</td><td>4730</td><td>CHABAUD</td><td>78 SPEC -</td><td>18.8 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> K<sup>0</sup> p</td></tr><tr><td>113 ± 4</td><td>1,3 MARTIN</td><td>78D SPEC</td><td>-</td><td>10 π<sup>-</sup> p → K<sup>0</sup><sub>S</sub> K<sup>-</sup> p</td></tr><tr><td>105 ± 8</td><td>2724</td><td>3 MARGULIE</td><td>76 SPEC -</td><td>23 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr><tr><td>113 ±19</td><td>730</td><td>FOLEY</td><td>72 CNTR -</td><td>20.3 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr><tr><td>123 ±13</td><td>1500</td><td>3 GRAVER</td><td>71 ASPK +</td><td>17.2 π<sup>-</sup> p → K<sup>-</sup> K<sup>0</sup><sub>S</sub> p</td></tr></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>120 ±15</td><td>870</td><td>4 SCHEGELSKY</td><td>06A RVUE 0</td><td>γγ → K<sup>0</sup><sub>S</sub> K<sup>0</sup><sub>S</sub></td></tr><tr><td>121 ±51</td><td>1000</td><td>1,2 CLELAND</td><td>82B SPEC +</td><td>30 π<sup>+</sup> p → K<sup>0</sup><sub>S</sub> K<sup>+</sup> p</td></tr><tr><td>110 ±18</td><td>350</td><td>HYAMS</td><td>78 ASPK +</td><td>12.7 π<sup>+</sup> p → K<sup>+</sup> K<sup>0</sup><sub>S</sub> p</td></tr></table>

¹ From a fit to $J^P = 2^+ \text{ partial wave.}$

² Number of events evaluated by us.

³ Width errors enlarged by us to $4\Gamma/\sqrt{N}$; see the note with the $K^*(892)$ mass.

⁴ From analysis of L3 data at 91 and 183–209 GeV.

ηπ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT

The data in this block is included in the average printed for a previous datablock.

111.1 ± 2.4 OUR AVERAGE

<table><tr><td>115 ±20</td><td></td><td>BARBERIS</td><td>00H</td><td>450 pp → p<sub>f</sub> π<sub>f</sub> π<sub>0</sub> p<sub>S</sub></td></tr><tr><td>112 ±14</td><td></td><td>BARBERIS</td><td>00H</td><td>450 pp → Δ<sup>+</sup><sub>f</sub> π<sub>0</sub> p<sub>S</sub></td></tr><tr><td>112 ± 3 ±2</td><td></td><td>1 AMSLER</td><td>94D CBAR</td><td>0.0 p<sub>f</sub> → π<sup>0</sup> π<sup>0</sup> η</td></tr><tr><td>103 ± 6 ±3</td><td></td><td>BELADIDZE</td><td>93 VES</td><td>37 π<sup>-</sup> N → ηπ<sup>-</sup> N</td></tr><tr><td>112.2 ± 5.7</td><td>2561</td><td>DELFOSSE</td><td>81 SPEC +</td><td>π<sup>±</sup> p → pπ<sup>±</sup> η</td></tr><tr><td>116.6 ± 7.7</td><td>1653</td><td>DELFOSSE</td><td>81 SPEC -</td><td>π<sup>±</sup> p → pπ<sup>±</sup> η</td></tr><tr><td>108 ± 9</td><td>1000</td><td>KEY</td><td>73 OSPK -</td><td>6 π<sup>-</sup> p → pπ<sup>-</sup> η</td></tr></table>
• • • We do not use the following data for averages, fits, limits, etc. • • •

112 ± 1 ±8 2 JACKURA 18 RVUE π⁻p → ηπ⁻p

119 ±14 3 ADOLPH 15 COMP 191 π⁻p → η(ℓ')π⁻p

127 ± 2 ±2 4 THOMPSON 97 MPS 18 π⁻p → ηπ⁻p

118 ±10 ARMSTRONG 93c E760 0 p̄p → π⁰ηη → 6γ

104 ± 9 6200 5 CONFORTO 73 OSPK → 6 π⁻p → pMM⁻

¹The systematic error of 2 MeV corresponds to the spread of solutions.

²Superseded by RODAS 19.

³ADOLPH 15 value is derived from a Breit-Wigner fit with mass-dependent width taking the ηπ and ρπ channels into account.

⁴Resolution is not unfolded.

⁵Missing mass with enriched MMS = ηπ⁻, η = 2γ.

η'π MODE

VALUE (MeV) DOCUMENT ID TECN COMMENT

The data in this block is included in the average printed for a previous datablock.

119 ± 25 OUR AVERAGE

140 ± 35 ± 20 IVANOV 01 B852 18 π⁻p → η'π⁻p

106 ± 32 BELADIDZE 93 VES 37 π⁻N → η'π⁻N

a₂(1320) DECAY MODES

<table><thead><tr><th>Mode</th><th>Fraction (Γ<sub>j</sub>/Γ)</th><th>Scale factor/ Confidence level</th></tr></thead><tbody><tr><td>Γ<sub>1</sub> 3π</td><td>(70.1 ± 2.7) %</td><td>S=1.2</td></tr><tr><td>Γ<sub>2</sub> ρ(770)π</td><td></td><td></td></tr><tr><td>Γ<sub>3</sub> f<sub>2</sub>(1270)π</td><td></td><td></td></tr><tr><td>Γ<sub>4</sub> ρ(1450)π</td><td></td><td></td></tr><tr><td>Γ<sub>5</sub> ηπ</td><td>(14.5 ± 1.2) %</td><td></td></tr><tr><td>Γ<sub>6</sub> ωππ</td><td>(10.6 ± 3.2) %</td><td>S=1.3</td></tr><tr><td>Γ<sub>7</sub> K<span style="text-decoration: overline">K</span></td><td>( 4.9 ± 0.8) %</td><td></td></tr><tr><td>Γ<sub>8</sub> η'(958)π</td><td>( 5.5 ± 0.9) × 10<sup>-3</sup></td><td></td></tr><tr><td>Γ<sub>9</sub> π<sup>±</sup>γ</td><td>( 2.91 ± 0.27) × 10<sup>-3</sup></td><td></td></tr><tr><td>Γ<sub>10</sub> γγ</td><td>( 9.4 ± 0.7) × 10<sup>-6</sup></td><td></td></tr><tr><td>Γ<sub>11</sub> e<sup>+</sup>e<sup>-</sup></td><td>&lt; 5 × 10<sup>-9</sup></td><td>CL=90%</td></tr></tbody></table>

CONSTRAINED FIT INFORMATION

An overall fit to 5 branching ratios uses 18 measurements and one constraint to determine 4 parameters. The overall fit has a χ² = 9.3 for 15 degrees of freedom.

The following off-diagonal array elements are the correlation coefficients (δxᵢδxⱼ)/(δxᵢ·δxⱼ), in percent, from the fit to the branching fractions, xᵢ ≡ Γᵢ/Γₜotal. The fit constrains the xᵢ whose labels appear in this array to sum to one.

<figure><img src="image_459.png" /></figure>

a₂(1320) PARTIAL WIDTHS

Γ(ηπ)

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT Γ₅

• • • We do not use the following data for averages, fits, limits, etc. • • •

18.5 ±3.0 870 ¹ SCHEGELSKY 06A RVUE 0 γγ → K⁰S K⁰S

¹From analysis of L3 data at 91 and 183–209 GeV, using Γ(a₂(1320) → γγ) = 0.91 keV and SU(3) relations.

Γ(KK̄)

VALUE (MeV) EVTS DOCUMENT ID TECN CHG COMMENT Γ₇

• • • We do not use the following data for averages, fits, limits, etc. • • •

7.0 ±2.0 1.5 870 ¹ SCHEGELSKY 06A RVUE 0 γγ → K⁰S K⁰S

¹From analysis of L3 data at 91 and 183–209 GeV, using Γ(a₂(1320) → γγ) = 0.91 keV and SU(3) relations.

Γ(π±γ)

VALUE (keV) EVTS DOCUMENT ID TECN CHG COMMENT Γ₉

311 ± 25 OUR AVERAGE 358 ± 6 ± 42 1 ADOLPH 14 COMP → 190 π⁻Pb → π⁺π⁻π⁻Pb'

284 ± 25 ± 25 7.1k MOLCHANOV 01 SELX 600 π⁻A → π⁺π⁻π⁻A

295 ± 60 CIHANGIR 82 SPEC + 200 π⁺A

• • • We do not use the following data for averages, fits, limits, etc. • • •

461 ± 110 2 MAY 77 SPEC ± 9.7 γA

¹Primakoff reaction using a₂(1320) → 3π branching ratio of 70.1%.

²Assuming one-pion exchange.

Γ(γγ)

<table><thead><tr><th>VALUE (keV)</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>CHG</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="6"><strong>1.00 ± 0.06 OUR AVERAGE</strong></td></tr><tr><td>0.98 ± 0.05 ± 0.09</td><td></td><td>ACCIARRI</td><td>97T</td><td>L3</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>+</sup>π<sup>+</sup>π<sup>-</sup>η<sup>0</sup></td></tr><tr><td>0.96 ± 0.03 ± 0.13</td><td></td><td>ALBRECHT</td><td>97B</td><td>ARG</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>+</sup>π<sup>+</sup>π<sup>-</sup>η<sup>0</sup></td></tr><tr><td>1.26 ± 0.26 ± 0.18</td><td>36</td><td>BARU</td><td>90</td><td>MD1</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>+</sup>π<sup>+</sup>π<sup>-</sup>η<sup>0</sup></td></tr><tr><td>1.00 ± 0.07 ± 0.15</td><td>415</td><td>BEHREND</td><td>90c</td><td>CELL 0</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>+</sup>π<sup>+</sup>π<sup>-</sup>η<sup>0</sup></td></tr><tr><td>1.03 ± 0.13 ± 0.21</td><td></td><td>BUTLER</td><td>90</td><td>MRK2</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>+</sup>π<sup>+</sup>π<sup>-</sup>η<sup>0</sup></td></tr><tr><td>1.01 ± 0.14 ± 0.22</td><td>85</td><td>OEST</td><td>90</td><td>JADE</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>3π</td></tr><tr><td>0.90 ± 0.27 ± 0.15</td><td>56</td><td>1 ALTHOFF</td><td>86</td><td>TASS 0</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>π<sup>0</sup>η</td></tr><tr><td>1.14 ± 0.20 ± 0.26</td><td></td><td>2 ANTREASYAN 86</td><td>CBAL 0</td><td></td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>π<sup>0</sup>η</td></tr><tr><td>1.06 ± 0.18 ± 0.19</td><td></td><td>BERGER</td><td>84c</td><td>PLUT 0</td><td>e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>3π</td></tr></tbody></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.81 ± 0.19 ± 0.42 35 1 BEHREND 82c CELL 0 e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>3π

0.77 ± 0.18 ± 0.27 22 2 EDWARDS 82F CBAL 0 e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>π<sup>0</sup>η

¹From ρπ decay mode.

²From ηπ⁰ decay mode.

Γ(e⁺e⁻)

<table><thead><tr><th>VALUE (eV)</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td><strong>&lt; 0.56</strong></td><td>90</td><td>ACHASOV</td><td>00k</td><td>SND</td><td>e<sup>+</sup>e<sup>-</sup> → π<sup>0</sup>η<sup>0</sup></td></tr><tr><td colspan="6"><strong>• • • We do not use the following data for averages, fits, limits, etc. • • •</strong></td></tr><tr><td>&lt;25</td><td>90</td><td>VOROBYEV</td><td>88</td><td>ND</td><td>e<sup>+</sup>e<sup>-</sup> → π<sup>0</sup>η</td></tr></tbody></table>

a₂(1320) Γ(i)Γ(γγ)/Γ(total)

Γ(3π) × Γ(γγ)/Γₜotal

VALUE (keV) EVTS DOCUMENT ID TECN COMMENT Γ₁Γ₁₀/Γ

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.65 ± 0.02 ± 0.02 18k ¹ SCHEGELSKY 06 RVUE γγ → π⁺π⁻π⁰

¹From analysis of L3 data at 183–209 GeV.

Γ(ηπ) × Γ(γγ)/Γₜotal

VALUE (keV) DOCUMENT ID TECN COMMENT Γ₅Γ₁₀/Γ

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.145 ± 0.097 1 UEHARA 09A BELL e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>ηπ⁰

¹From the D₂-wave. The fraction of the D₀-wave is 3.4 ± 2.3%.

Γ(KK̄) × Γ(γγ)/Γₜotal

VALUE (keV) EVTS DOCUMENT ID TECN COMMENT Γ₇Γ₁₀/Γ

0.126 ± 0.007 ± 0.028 1 ALBRECHT 90g ARG e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>K<sup>+</sup>K<sup>-</sup>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.081 ± 0.006 ± 0.027 2 ALBRECHT 90g ARG e<sup>+</sup>e<sup>-</sup> → e<sup>+</sup>e<sup>-</sup>K<sup>+</sup>K<sup>-</sup>

¹Using an incoherent background.

²Using a coherent background.

a₂(1320) BRANCHING RATIOS

Γ(Γ<sub>f2</sub>(1270)π) + Γ(ρ(1450)π))/Γ(ρ(770)π)

<table><thead><tr><th>VALUE</th><th>CL%</th><th>DOCUMENT ID</th><th>TECN</th><th>CHG</th><th>COMMENT</th></tr></thead><tbody><tr><td>&lt;0.12</td><td></td><td>ABRAMOVI... 70B</td><td>HBC</td><td>-</td><td>3.93 π<sup>-</sup>p</td></tr></tbody></table>

Γ(ρ(770)π)/Γ(Γ<sub>f2</sub>(1270)π)

<table><thead><tr><th>VALUE</th><th>EVTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>16.5 ± 1.2</td><td>46M</td><td>1 AGHASYAN</td><td>18B</td><td>COMP 190 π<sup>-</sup>p → π<sup>-</sup>π<sup>+</sup>π<sup>-</sup>p</td></tr></tbody></table>

¹Statistical error negligible.

Γ(ηπ)/Γ(3π)

VALUE (keV) EVTS DOCUMENT ID TECN CHG COMMENT Γ₅/Γ₁

0.207 ± 0.018 OUR FIT

0.213 ± 0.020 OUR AVERAGE

0.18 ± 0.05 52 FORINO 76 HBC 11 π⁻p

0.22 ± 0.05 52 ANTIPOV 73 CNTR - 40 π⁻p

0.211 ± 0.044 149 CHALOUPKA 73 HBC + 3.9 π⁻p

0.246 ± 0.042 167 ALSTON... 71 HBC + 7.0 π⁺p

0.25 ± 0.09 15 BOECKMANN 70 HBC + 5.0 π⁺p

0.23 ± 0.08 22 ASCOLI 68 HBC - 5 π⁻p

0.12 ± 0.08 22 CHUNG 68 HBC - 3.2 π⁻p

0.22 ± 0.09 22 CONTE 67 HBC - 11.0 π⁻p

Γ(ωππ)/Γ(3π)

VALUE (keV) EVTS DOCUMENT ID TECN CHG COMMENT Γ₆/Γ₁

0.15 ± 0.05 OUR FIT Error includes scale factor of 1.3.

0.15 ± 0.05 OUR AVERAGE Error includes scale factor of 1.3. See the ideogram below.

0.28 ± 0.09 60 DIAZ 74 DBC 0 6 π⁺n

0.18 ± 0.08 74 KARSHON 74 HBC Avg. of above two

0.10 ± 0.05 279 CHALOUPKA 73 HBC - 3.9 π⁻p
• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>0.29 ± 0.08</td><td>140</td><td>1 KARSHON</td><td>74</td><td>HBC</td><td>0</td><td>4.9 π<sup>+</sup> p</td></tr><tr><td>0.10 ± 0.04</td><td>60</td><td>1 KARSHON</td><td>74</td><td>HBC</td><td>+</td><td>4.9 π<sup>+</sup> p</td></tr><tr><td>0.19 ± 0.08</td><td></td><td>DEFOIX</td><td>73</td><td>HBC</td><td>0</td><td>0.7 p̄p</td></tr></table>

1 KARSHON 74 suggest an additional $I = 0$ state strongly coupled to $ωππ$ which could explain discrepancies in branching ratios and masses. We use a central value and a systematic spread.

2 Decays to $b_1(1040)π, π_1 → ωπ$. Error increased to account for possible systematic errors of complicated analysis.

WEIGHTED AVERAGE
0.15±0.05 (Error scaled by 1.3)

<figure><img src="image_460.png" /></figure>

Values above of weighted average, error, and scale factor are based upon the data in this ideogram only. They are not necessarily the same as our 'best' values. Obtained from a least-squares constrained fit utilizing measurements of other (related) quantities as additional information.

$$ \begin{array}{lcccccc} \Gamma(\mathbf{K}\bar{\mathbf{K}})/\Gamma(\mathbf{3}\pi) & \Gamma_7/\Gamma_1 & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.070±0.012} \end{array} & \begin{array}{l} \text{EVTS} \\ \text{0.078±0.017} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{CHABAUD} \end{array} & \begin{array}{l} \text{TECN} \\ \text{78} \end{array} & \begin{array}{l} \text{CHG} \\ \text{RVUE} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>0.011 ± 0.003</td><td>1 BERTIN</td><td>98B</td><td>OBLX</td><td>0.0 p̄p → K<sup>±</sup> K<sub>S</sub> π<sup>∓</sup></td></tr><tr><td>0.056 ± 0.014</td><td>50</td><td>2 CHALOUPKA</td><td>73</td><td>HBC</td><td>− 3.9 π<sup>−</sup> p</td></tr><tr><td>0.097 ± 0.018</td><td>113</td><td>2 ALSTON...</td><td>71</td><td>HBC</td><td>+</td><td>7.0 π<sup>+</sup> p</td></tr><tr><td>0.06 ± 0.03</td><td></td><td>2 ABRAMOVI...</td><td>70B</td><td>HBC</td><td>− 3.93 π<sup>−</sup> p</td></tr><tr><td>0.054 ± 0.022</td><td></td><td>2 CHUNG</td><td>68</td><td>HBC</td><td>− 3.2 π<sup>−</sup> p</td></tr></table>

¹ Using 4π data from BERTIN 97D.

² Included in CHABAUD 78 review.

$$ \begin{array}{lcccccc} \Gamma(\mathbf{K}\bar{\mathbf{K}})/\Gamma(\eta\pi) & \Gamma_7/\Gamma_5 & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.070±0.012} \end{array} & \begin{array}{l} \text{EVTS} \\ \text{0.078±0.017} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{CHABAUD} \end{array} & \begin{array}{l} \text{TECN} \\ \text{78} \end{array} & \begin{array}{l} \text{CHG} \\ \text{RVUE} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

<table><tr><td>0.31 ± 0.22 <sup>+0.09</sup><sub>-0.11</sub></td><td>1 KOPF</td><td>21</td><td>RVUE</td><td>0.9 p̄p → π<sup>0</sup> π<sup>0</sup> η<sub>1</sub>, π<sup>0</sup> K<sup>+</sup> K<sup>−</sup> and 191 π<sup>−</sup> p → π<sup>−</sup> π<sup>−</sup> π<sup>+</sup> p</td></tr><tr><td>0.352 ± 0.011 ± 0.175</td><td>2 ALBRECHT</td><td>20</td><td>RVUE</td><td>0.9 p̄p → π<sup>0</sup> π<sup>0</sup> η<sub>1</sub>, π<sup>0</sup> η<sub>1</sub>, π<sup>0</sup> K<sup>+</sup> K<sup>−</sup></td></tr><tr><td>0.08 ± 0.02</td><td>3 BERTIN</td><td>98B</td><td>OBLX</td><td>0.0 p̄p → K<sup>±</sup> K<sub>S</sub> π<sup>∓</sup></td></tr></table>

¹ From T-matrix pole based on combined fit of Crystal Barrel and $ππ$ scattering data (ALBRECHT 20), and COMPASS data (ADOLPH 15), using a coupled-channel model of $ηπ, η'π$ and $K\bar{K}$ systems.

² Residues from T-matrix pole with 2 poles, 2 channels ($π^0η$ and $K\bar{K}$).

³ Using $ηπππ$ data from AMSLER 94D.

$$ \begin{array}{lcccccc} \Gamma(\eta\pi)/[\Gamma(3\pi) + \Gamma(\eta\pi) + \Gamma(\mathbf{K}\bar{\mathbf{K}})] & \Gamma_5/(\Gamma_1+\Gamma_5+\Gamma_7) & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.162±0.012} \end{array} & \begin{array}{l} \text{EVTS} \\ \text{0.140±0.028} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{ESPIGAT} \end{array} & \begin{array}{l} \text{TECN} \\ \text{72} \end{array} & \begin{array}{l} \text{CHG} \\ \text{HBC} \pm 0.0 p̄p \end{array} & & \\ & & & & & & \\ \text{0.13 ± 0.04} & & & & & & \\ \text{0.15 ± 0.04} & 34 & & & & & \\ \end{array} $$

$$ \begin{array}{lcccccc} \Gamma(\mathbf{K}\bar{\mathbf{K}})/[\Gamma(3\pi) + \Gamma(\eta\pi) + \Gamma(\mathbf{K}\bar{\mathbf{K}})] & \Gamma_7/(\Gamma_1+\Gamma_5+\Gamma_7) & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.054±0.009} \end{array} & \begin{array}{l} \text{EVTS} \\ \text{0.048±0.012} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{TOET} \end{array} & \begin{array}{l} \text{TECN} \\ \text{73} \end{array} & \begin{array}{l} \text{CHG} \\ \text{HBC} \pm 5.0 p̄p \end{array} & & \\ & & & & & & \\ \text{0.05 ± 0.02} & & & & & & \\ \text{0.09 ± 0.04} & & & & & & \\ \text{0.03 ± 0.02} & 8 & & & & & \\ \text{0.06 ± 0.03} & 17 & & & & & \\ \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>0.020 ± 0.004</td><td>2 ESPIGAT</td><td>72</td><td>HBC</td><td>± 0.0 p̄p</td></tr></table>

¹ Montanet agrees. Viuda.

² Not averaged because of discrepancy between masses from $K\bar{K}$ and $ρπ$ modes.

$$ \begin{array}{lcccccc} \Gamma(\eta'(958)\pi)/\Gamma_{\text{total}} & \Gamma_8/\Gamma & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.038±0.005} \end{array} & \begin{array}{l} \text{CL%} \\ \text{0.004±0.004} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{EISENSTEIN} \end{array} & \begin{array}{l} \text{TECN} \\ \text{90} \end{array} & \begin{array}{l} \text{CHG} \\ \text{97C} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>&lt;0.006</td><td>95</td><td>ALDE</td><td>92B</td><td>GAM2</td><td>38,100 π<sup>−</sup> p → η<sup>(1)</sup> π<sup>0</sup> n</td></tr><tr><td>&lt;0.02</td><td>97</td><td>BARNHAM</td><td>71</td><td>HBC</td><td>+</td><td>3.7 π<sup>+</sup> p</td></tr><tr><td>0.004±0.004</td><td></td><td>1 BOESEBECK</td><td>68</td><td>HBC</td><td>+</td><td>8 π<sup>+</sup> p</td></tr></table>

¹ No longer valid since $Γ(K\bar{K})/Γ(3π)$ value has changed (MORRISON 71).

$$ \begin{array}{lcccccc} \Gamma(\eta'(958)\pi)/\Gamma(3\pi) & \Gamma_8/\Gamma_1 & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.038±0.005} \end{array} & \begin{array}{l} \text{CL%} \\ \text{0.004±0.004} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{EISENSTEIN} \end{array} & \begin{array}{l} \text{TECN} \\ \text{73} \end{array} & \begin{array}{l} \text{CHG} \\ \text{90} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>&lt;0.011</td><td>90</td><td>EISENSTEIN</td><td>73</td><td>HBC</td><td>− 5 π<sup>−</sup> p</td></tr><tr><td>&lt;0.04</td><td></td><td>ALSTON...</td><td>71</td><td>HBC</td><td>+</td><td>7.0 π<sup>+</sup> p</td></tr><tr><td>0.04 ± 0.03</td><td></td><td>BOECKMANN</td><td>70</td><td>HBC</td><td>0</td><td>5.0 π<sup>+</sup> p</td></tr></table>

$$ \begin{array}{lcccccc} \Gamma(\eta'(958)\pi)/\Gamma(\eta\pi) & \Gamma_8/\Gamma_5 & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.038±0.005} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{EISENSTEIN} \end{array} & \begin{array}{l} \text{TECN} \\ \text{90} \end{array} & & \begin{array}{l} \text{CHG} \\ \text{97C} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

<table><tr><td>0.05 ± 0.02</td><td>ADOLPH</td><td>15</td><td>COMP</td><td>191 π<sup>−</sup> p → η<sup>(1)</sup> π<sup>−</sup> p</td></tr><tr><td>0.032 ± 0.009</td><td>ABELE</td><td>97C</td><td>CBAR</td><td>0.0 p̄p → π<sup>0</sup> π<sup>0</sup> η<sub>1</sub></td></tr><tr><td>0.047 ± 0.010 ± 0.004</td><td>1 BELADIDZE</td><td>93</td><td>VES</td><td>37 π<sup>−</sup> N → a<sub>2</sub><sup>−</sup> N</td></tr><tr><td>0.034 ± 0.008 ± 0.005</td><td>BELADIDZE</td><td>92</td><td>VES</td><td>36 π<sup>−</sup> C → a<sub>2</sub><sup>−</sup> C</td></tr></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>0.046 ± 0.015 <sup>+0.07</sup><sub>-0.06</sub></td><td>2 KOPF</td><td>21</td><td>RVUE</td><td>0.9 p̄p → π<sup>0</sup> π<sup>0</sup> η<sub>1</sub>, π<sup>0</sup> η<sub>1</sub>, π<sup>0</sup> K<sup>+</sup> K<sup>−</sup> and 191 π<sup>−</sup> p → π<sup>−</sup> π<sup>−</sup> π<sup>+</sup> p</td></tr></table>

¹ Using $B(η' → π^+π^-η) = 0.441$, $B(η → γγ) = 0.389$ and $B(η → π^+π^-π^0) = 0.236$.

² From T-matrix pole based on combined fit of Crystal Barrel and $ππ$ scattering data (ALBRECHT 20), and COMPASS data (ADOLPH 15), using a coupled-channel model of $ηπ, η'π$ and $K\bar{K}$ systems.

$$ \begin{array}{lcccccc} \Gamma(\pi^±γ)/\Gamma_{\text{total}} & \Gamma_9/\Gamma & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.005±0.005} \end{array} & \begin{array}{l} \text{CL%} \\ \text{0.004±0.004} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{EISENBERG} \end{array} & \begin{array}{l} \text{TECN} \\ \text{72} \end{array} & \begin{array}{l} \text{CHG} \\ \text{4.3,5,25,7.5 γp} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

¹ Pion-exchange model used in this estimation.

$$ \begin{array}{lcccccc} \Gamma(e^+e^-)/\Gamma_{\text{total}} & \Gamma_{11}/\Gamma & & & & & \\ \begin{array}{l} \text{VALUE} \\ \text{0.001±0.001} \end{array} & \begin{array}{l} \text{CL%} \\ \text{0.004±0.004} \end{array} & \begin{array}{l} \text{DOCUMENT ID} \\ \text{EISENBERG} \end{array} & \begin{array}{l} \text{TECN} \\ \text{90} \end{array} & \begin{array}{l} \text{CHG} \\ \text{00K} \end{array} & & \\ & & & & & & \\ \text{•••} & & & & & & \\ \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tr><td>&lt;6</td><td>90</td><td>ACHASOV</td><td>00K</td><td>SND</td><td>e<sup>+</sup> e<sup>−</sup> → π<sup>0</sup> π<sup>0</sup></td></tr></table>

## a₂(1320) REFERENCES

<table><tr><td>KOPF</td><td>21</td><td>EJPC81</td><td>1056</td><td>(BOCH)</td></tr><tr><td>ALBRECHT</td><td>20</td><td>EJPC80</td><td>453</td><td>(Crystal Barrel Collab.)</td></tr><tr><td>RODAS</td><td>19</td><td>PRL122</td><td>042002</td><td>(JPAC Collab.)</td></tr><tr><td>AGHASYAN</td><td>18B</td><td>PR D98</td><td>092003</td><td>(COMPASS Collab.)</td></tr><tr><td>JACKURA</td><td>18</td><td>PLB779</td><td>464</td><td>(JPAC and COMPASS Collab.)</td></tr><tr><td>ADOLPH</td><td>15</td><td>PLB740</td><td>303</td><td>(COMPASS Collab.)</td></tr><tr><td>ADOLPH</td><td>14</td><td>PLA50</td><td>79</td><td>(COMPASS Collab.)</td></tr><tr><td>ALEKSEEV</td><td>10</td><td>PRL104</td><td>241803</td><td>(COMPASS Collab.)</td></tr><tr><td>ANISOVICH</td><td>9</td><td>IMPJ</td><td>A24</td><td>2481</td><td>(PNPI)</td></tr><tr><td>UEHARA</td><td>09A</td><td>PRD80</td><td>032001</td><td>(BELLE Collab.)</td></tr><tr><td>SCHEGELSKY</td><td>06</td><td>EJPC</td><td>279</td><td>V.A. Schegelsky et al.</td></tr><tr><td>SCHEGELSKY</td><td>06A</td><td>EJPC</td><td>270</td><td>V.A. Schegelsky et al.</td></tr><tr><td>CHUNG</td><td>02</td><td>PRD65</td><td>072001</td><td>S.U. Chung et al.</td></tr><tr><td>IVANOV</td><td>01</td><td>PLR</td><td>86</td><td>E.I. Ivanov et al.</td></tr><tr><td>MOLCHANOV</td><td>01</td><td>PLB521</td><td>171</td><td>V.V. Molchanov et al.</td></tr><tr><td>ACHASOV</td><td>00K</td><td>PLB492</td><td>8</td><td>M.N. Achasov et al.</td></tr><tr><td>BARBERIS</td><td>00H</td><td>PLB488</td><td>225</td><td>D. Barberis et al.</td></tr><tr><td>BARBERIS</td><td>98B</td><td>PLB422</td><td>399</td><td>D. Barberis et al.</td></tr><tr><td>BERTIN</td><td>98B</td><td>PLB434</td><td>180</td><td>A. Bertin et al.</td></tr><tr><td>ABELE</td><td>97C</td><td>PLB404</td><td>179</td><td>A. Abele et al.</td></tr><tr><td>ACIARRI</td><td>97T</td><td>PLB413</td><td>147</td><td>M. Acilcarri et al.</td></tr><tr><td>ALBRECHT</td><td>97B</td><td>ZPHY</td><td>74</td><td>469</td><td>(L3 Collab.)</td></tr><tr><td>THOMPSON</td><td>94</td><td>PLB79</td><td>1630</td><td>D.R. Thompson et al.</td></tr><tr><td>AMELIN</td><td>96</td><td>ZPHY</td><td>70</td><td>C. Amelin et al.</td><td>(ARGUS Collab.)</td></tr><tr><td>AMSLER</td><td>94D</td><td>PLB333</td><td>277</td><td>D.V. Amelin et al.</td><td>(SERP, TBIL)</td></tr><tr><td>AOYAGI</td><td>93</td><td>PLB314</td><td>266</td><td>C. Amsler et al.</td><td>(Crystal Barrel Collab.)</td></tr><tr><td>ARMSTRONG</td><td>93C</td><td>PLB307</td><td>394</td><td>H. Aoyagi et al.</td><td>(BKEI Collab.)</td></tr><tr><td>BELADIDZE</td><td>93</td><td>PLB313</td><td>276</td><td>T.A. Armstrong et al.</td><td>(FNAL, FERR, GENO+)</td></tr><tr><td>CONDO</td><td>93</td><td>PLD48</td><td>3045</td><td>G.M. Beladidze et al.</td><td>(VES Collab.)</td></tr><tr><td>ALDE</td><td>92B</td><td>ZPHY</td><td>54</td><td>D. Condo et al.</td><td>(SLAC Hybrid Collab.)</td></tr><tr><td>BELADIDZE</td><td>92B</td><td>ZPHY</td><td>54</td><td>D.M. Alde et al.</td><td>(SERP, BELG, LANL, LAPP+)</td></tr><tr><td>ALBRECHT</td><td>90G</td><td>ZPHY</td><td>48</td><td>G.M. Beladidze et al.</td><td>(VES Collab.)</td></tr><tr><td>ARMSTRONG</td><td>90E</td><td>ZPHY</td><td>48</td><td>T.A. Armstrong, M. Benayoun, W. Beusch (WA76 Coll.)</td><td>(ARGUS Collab.)</td></tr><tr><td>BARU</td><td>90E</td><td>ZPHY</td><td>48</td><td>S.E. Baru et al.</td><td>(MD-1 Collab.)</td></tr><tr><td>BEHREND</td><td>90C</td><td>ZPHY</td><td>46</td><td>H.J. Behrend et al.</td><td>(CELLO Collab.)</td></tr><tr><td>BUTLER</td><td>90</td><td>PRD42</td><td>1368</td><td>F. Butler et al.</td><td>(Mark II Collab.)</td></tr><tr><td>OEST</td><td>90</td><td>ZPHY</td><td>47</td><td>T. Oest et al.</td><td>(JADE Collab.)</td></tr><tr><td>AUGUSTIN</td><td>89</td><td>NPB320</td><td>1</td><td>J.E. Augustin, G. Cosme</td><td>(DM2 Collab.)</td></tr><tr><td>VOROBYEV</td><td>88</td><td>PV</td><td>48</td><td>P.V. Vorobiev et al.</td><td>(NOVO)</td></tr><tr><td>ALTHOFF</td><td>86</td><td>ZPHY</td><td>31</td><td>436</td><td>(TASSO Collab.)</td></tr><tr><td>ANTREASYAN</td><td>86</td><td>PRD33</td><td>1847</td><td>D. Antreasyan et al.</td><td>(Crystal Ball Collab.)</td></tr><tr><td>BERGER</td><td>84C</td><td>PL149</td><td>427</td><td>C. Berger et al.</td><td>(PLUTO Collab.)</td></tr><tr><td>BEHREND</td><td>82C</td><td>PL114</td><td>378</td><td>H.J. Behrend et al.</td><td>(CELLO Collab.)</td></tr><tr><td>Also</td><td></td><td>PL125B</td><td>518 (errat.)</td><td>H.J. Behrend et al.</td><td>(CELLO Collab.)</td></tr><tr><td>CIHANGIR</td><td>82</td><td>PL117B</td><td>123</td><td>S. Cihangir et al.</td><td>(FNAL, MINN, ROCH)</td></tr><tr><td>CLELAND</td><td>82B</td><td>NPB208</td><td>228</td><td>W.E. Cleland et al.</td><td>(DURH, GEVA, LAUS+)</td></tr><tr><td>EDWARDS</td><td>82F</td><td>PL110B</td><td>82</td><td>C. Edwards et al.</td><td>(CIT, HARV, PRIN+)</td></tr></table>
<table><tr><td>DELFOSSÉ</td><td>81</td><td>NP B183 349</td><td>A. Delfossé et al. (GEVA, LAUS)</td></tr><tr><td>EVANGELIS</td><td>81</td><td>NP B175 197</td><td>C. Evangelista et al. (BARI, BONN, CERN+)</td></tr><tr><td>CHABAUD</td><td>80</td><td>NP B175 189</td><td>V. Chabaud et al. (CERN, MPIM, AMST)</td></tr><tr><td>DAUM</td><td>80C</td><td>PL 89B 276</td><td>C. Daum et al. (AMST, CERN, CRAC, MPIM+) JP</td></tr><tr><td>BALTAY</td><td>78B</td><td>PR D17 62</td><td>C. Baltay et al. (COLU, BING)</td></tr><tr><td>CHABAUD</td><td>78</td><td>NP B145 349</td><td>V. Chabaud et al. (CERN, MPIM)</td></tr><tr><td>FERRERSORIA</td><td>78</td><td>PL 74B 287</td><td>A. Ferrer Soria et al. (ORSAY, CERN, CDEF+)</td></tr><tr><td>HYAMS</td><td>78</td><td>NP B146 303</td><td>B.D. Hyams et al. (CERN, MPIM, ATEN)</td></tr><tr><td>MARTIN</td><td>78D</td><td>PL 74B 417</td><td>A.D. Martin et al. (DURH, GEVA) JP</td></tr><tr><td>MAY</td><td>77</td><td>PR D16 1983</td><td>E.N. May et al. (ROCH, CORN)</td></tr><tr><td>FORINO</td><td>76</td><td>NC 35A 465</td><td>A. Forino et al. (BGNA, FIRZ, GENO, MILA+)</td></tr><tr><td>MARGULIE</td><td>76</td><td>PR D14 667</td><td>M. Margulies et al. (BNL, CUNY)</td></tr><tr><td>EMMS</td><td>75</td><td>58B 117</td><td>M.J. Emms et al. (BIRM, DURH, RHEL) JP</td></tr><tr><td>WAGNER</td><td>75</td><td>PL 58B 201</td><td>F. Wagner, M. Tabak, D.M. Chew (LBL) JP</td></tr><tr><td>DIAZ</td><td>74</td><td>PRL 32 260</td><td>J. Diaz et al. (CASE, CMU)</td></tr><tr><td>KARSHON</td><td>74</td><td>PRL 32 852</td><td>U. Karshon et al. (REHO)</td></tr><tr><td>ANTIPOV</td><td>73</td><td>NP B63 175</td><td>Y.M. Antipov et al. (CERN, SERP) JP</td></tr><tr><td>ANTIPOV</td><td>73C</td><td>NP B63 153</td><td>Y.M. Antipov et al. (CERN, MPIM)</td></tr><tr><td>CHALOUPKA</td><td>73</td><td>PL 44B 211</td><td>V. Chaloupka et al. (CERN)</td></tr><tr><td>CONFORTO</td><td>73</td><td>PL 45B 154</td><td>G. Conforto et al. (EFI, FNAL, TNT0)</td></tr><tr><td>DEFOIX</td><td>73</td><td>PL 43B 141</td><td>C. Defoix et al. (CDEF)</td></tr><tr><td>EISENSTEIN</td><td>73</td><td>PR D7 278</td><td>L. Eisenstein et al. (ILL)</td></tr><tr><td>KEY</td><td>73</td><td>PRL 30 503</td><td>(TNT0, EFL, FNAL, WISC)</td></tr><tr><td>TOET</td><td>73</td><td>NP B63 248</td><td>(NIJM, BONN, DURH, TORI)</td></tr><tr><td>DAMERI</td><td>72</td><td>CN 9A 1</td><td>M. Dameri et al. (GENO, MILA, SACL)</td></tr><tr><td>EISENBERG</td><td>72</td><td>PR D5 15</td><td>Y. Eisenberg et al. (REHO, SLAC, TELA)</td></tr><tr><td>ESPIGAT</td><td>72</td><td>NP B36 93</td><td>P. Espigat et al. (CERN, CDEF)</td></tr><tr><td>FOLEY</td><td>72</td><td>PR D6 747</td><td>K.J. Foley et al. (BNL, CUNY)</td></tr><tr><td>ALSTON...</td><td>71</td><td>PL 34B 156</td><td>A. Alston-Garnjost et al. (LRL)</td></tr><tr><td>BARNHAM</td><td>71</td><td>PRL 26 1494</td><td>K.W.J. Barnham et al. (LRL)</td></tr><tr><td>BINNIE</td><td>71</td><td>PL 36B 257</td><td>D.M. Binnie et al. (LOIC, SHMP)</td></tr><tr><td>BOWEN</td><td>71</td><td>PRL 26 1663</td><td>D.R. Bowen et al. (NEAS, STON)</td></tr><tr><td>GRAYER</td><td>71</td><td>PL 34B 333</td><td>G. Grayer et al. (CERN, MPIM)</td></tr><tr><td>ABRAMOVIL</td><td>70B</td><td>NP B23 466</td><td>M. Abramovich et al. (CERN) JP</td></tr><tr><td>ALSTON...</td><td>70</td><td>PRL 33B 607</td><td>M. Alston-Garnjost et al. (LRL)</td></tr><tr><td>BOECKMANN</td><td>70</td><td>NP B16 221</td><td>K. Boeckmann et al. (BONN, DURH, NIJM+)</td></tr><tr><td>ASCOLI</td><td>68</td><td>PRL 20 1321</td><td>G. Ascoli et al. (ILL)</td></tr><tr><td>BOESEBECK</td><td>68</td><td>NP B4 501</td><td>K. Boesebeck et al. (AACH, BERL, CERN)</td></tr><tr><td>CHUNG</td><td>68</td><td>PR 165 1491</td><td>S.U. Chung et al. (LRL)</td></tr><tr><td>CONTE</td><td>67</td><td>NC 51A 175</td><td>F. Conte et al. (GENO, HAMB, MILA, SACL)</td></tr></table>

$f_0(1370)$

$I^G(J^{PC}) = 0^+(0^{++})$

See the review on "Spectroscopy of Light Meson Resonances" and a note on "Non-q̄q Candidates" in PDG 06, Journal of Physics G33 1 (2006).

$f_0(1370) \text{ T-MATRIX POLE } \sqrt{s}$

Note that $\Gamma = -2 \operatorname{Im}(\sqrt{s})$.

<table><thead><tr><th>VALUE (MeV)</th><th>DIRECT DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="4">(1250-1440) - i (60-300) OUR ESTIMATE</td></tr><tr><td>(1245 ± 40) - i (300<sup>+30</sup><sub>-70</sub>)</td><td>1</td><td>PELAEZ</td><td>RVUE Compilation</td></tr><tr><td>(1380<sup>+70</sup><sub>-60</sub>) - i (220<sup>+80</sup><sub>-70</sub>)</td><td>2</td><td>PELAEZ</td><td>RVUE Compilation</td></tr><tr><td>(1370 ± 40) - i (195 ± 20)</td><td>1</td><td>SARANTSEV</td><td>RVUE J/ψ(1S) → γ (ππ, K<sup>K</sup>, ηη, ωω)</td></tr><tr><td>(1280.6 ± 1.6 ± 47.4) - i (205.2 ± 1.7 ± 20.7)</td><td>3</td><td>ALBRECHT</td><td>RVUE 0.9 p̄p → π<sup>0</sup>π<sup>0</sup>ηη, π<sup>0</sup>ηη, π<sup>0</sup>K<sup>+</sup>K<sup>-</sup></td></tr><tr><td>(1290 ± 50) - i (170<sup>+20</sup><sub>-40</sub>)</td><td>4</td><td>ANISOVICH</td><td>RVUE 0.0 p̄p → ππ, N</td></tr><tr><td>(1373 ± 15) - i (137 ± 10)</td><td>5</td><td>BARGIOTTI</td><td>003 OBLX p̄p</td></tr><tr><td>(1302 ± 17) - i (166 ± 18)</td><td>6</td><td>BARBERIS</td><td>004 450 pp → p̄f 4πp<sub>S</sub></td></tr><tr><td>(1312 ± 25 ± 10) - i (109 ± 22 ± 15)</td><td>99</td><td>BARBERIS</td><td>000 OMEG 450 pp → K<sup>+</sup>K<sup>-</sup>, π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>(1406 ± 19) - i (80 ± 6)</td><td>7</td><td>KAMINSKI</td><td>99 RVUE ππ → ππ, K<sup>K</sup>, σσ</td></tr><tr><td>(1300 ± 20) - i (120 ± 20)</td><td>98B</td><td>ANISOVICH</td><td>RVUE Compilation</td></tr><tr><td>(1290 ± 15) - i (145 ± 15)</td><td>97B</td><td>BARBERIS</td><td>97B OMEG 450 pp → pp2(π<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>(1548 ± 40) - i (560 ± 40)</td><td>97C</td><td>OBLX</td><td>0.0 p̄p → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>(1380 ± 40) - i (180 ± 25)</td><td>96B</td><td>CBAR</td><td>0.0 p̄p → π<sup>0</sup>K<sup>0</sup>K<sup>0</sup>L<sup>0</sup></td></tr><tr><td>(1300 ± 15) - i (115 ± 8)</td><td>96</td><td>RVUE</td><td>RVUE ππ → ππ, K<sup>K</sup></td></tr><tr><td>(1330 ± 50) - i (150 ± 40)</td><td>8</td><td>AMSLER</td><td>95B CBAR p̄p → 3π<sup>0</sup></td></tr><tr><td>(1360 ± 35) - i (150-300)</td><td>9</td><td>AMSLER</td><td>95C CBAR p̄p → π<sup>0</sup>ηη</td></tr><tr><td>(1390 ± 30) - i (190 ± 40)</td><td>9</td><td>AMSLER</td><td>95D CBAR p̄p → 3π<sup>0</sup>, π<sup>0</sup>ηη, π<sup>0</sup>η<sup>0</sup>η</td></tr><tr><td>1346 - i249</td><td>10,11</td><td>JANSSEN</td><td>95 RVUE ππ → ππ, K<sup>K</sup></td></tr><tr><td>1214 - i168</td><td>11,12</td><td>TORNQVIST</td><td>95 RVUE ππ → ππ, K<sup>K</sup>, K<sup>K</sup>, ηη</td></tr><tr><td>1364 - i139</td><td></td><td>AMSLER</td><td>94D CBAR p̄p → π<sup>0</sup>π<sup>0</sup>η</td></tr><tr><td>(1365<sup>+20</sup><sub>-20</sub>) - i (134 ± 35)</td><td></td><td>ANISOVICH</td><td>94 CBAR p̄p → 3π<sup>0</sup>, π<sup>0</sup>ηη</td></tr><tr><td>(1340 ± 40) - i (127<sup>+30</sup><sub>-20</sub>)</td><td>13</td><td>BUGG</td><td>94 RVUE p̄p → 3π<sup>0</sup>, ηηη<sup>0</sup>, ηη<sup>0</sup>π<sup>0</sup></td></tr><tr><td>(1430 ± 5) - i (73 ± 13)</td><td>14</td><td>KAMINSKI</td><td>94 RVUE ππ → ππ, K<sup>K</sup></td></tr><tr><td>1420 - i220</td><td>15</td><td>AU</td><td>97 RVUE ππ → ππ, K<sup>K</sup></td></tr></tbody></table>

1 From forward dispersion relation applied to $\pi\pi$ scattering data.

2 From partial-wave dispersion relation applied to $\pi\pi \to K\bar{K}$ data.

3 T-matrix pole, 5 poles, 5 channels, including scattering data from HYAMS 75 ($\pi\pi$), LONGACRE 86 ($K\bar{K}$), BINON 83 ($\eta\eta$), and BINON 84c ($\eta\eta'$).

4 Another pole is found at $(1510 \pm 130) - i (800 \pm 150)$ MeV.

5 Coupled channel analysis of $\pi^+\pi^-\pi^0, K^+K^-\pi^0$, and $K^\pm K_0^S\pi^\mp$.

6 Average between $\pi^+\pi^- 2\pi^0$ and $2(\pi^+\pi^-)$.

7 T-matrix pole on sheet ---.

8 Supersedes ANISOVICH 94.

9 Coupled-channel analysis of p̄p → 3π<sup>0</sup>, π<sup>0</sup>ηη, and π<sup>0</sup>π<sup>0</sup>η on sheet IV. Demonstrates explicitly that f₀(500) and f₀(1370) are two different poles.

10 Analysis of data from FALVARD 88.

11 The pole is on Sheet III. Demonstrates explicitly that $f_0(500)$ and $f_0(1370)$ are two different poles.

12 Uses data from BEIER 72B, OCHS 73, HYAMS 73, GRAYER 74, ROSSELET 77, CA-SON 83, ASTON 88, and ARMSTRONG 91B. Coupled channel analysis with flavor symmetry and all light two-pseudoscalars systems.

13 Reanalysis of ANISOVICH 94 data.

14 T-matrix pole on sheet III.

15 Analysis of data from OCHS 73, GRAYER 74, BECKER 79, and CASON 83.

$f_0(1370) \text{ BREIT-WIGNER MASS}$

<table><thead><tr><th>VALUE (MeV)</th><th>EVENTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5">1200 to 1500 OUR ESTIMATE</td></tr><tr><td colspan="5">ππ MODE</td></tr><tr><td>1400 ± 40</td><td></td><td>1 AUBERT</td><td>09L</td><td>BABR B<sup>±</sup> → π<sup>±</sup>π<sup>±</sup>π<sup>∓</sup></td></tr><tr><td>1470<sup>+6</sup><sub>-7</sub> ± 72</td><td></td><td>2 UEHARA</td><td>08A</td><td>BELL 10.6 e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup>π<sup>0</sup>π<sup>0</sup></td></tr><tr><td>1259 ± 55</td><td>2.6k</td><td>BONVICINI</td><td>07</td><td>CLEO D<sup>+</sup> → π<sup>+</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1309 ± 1 ± 15</td><td></td><td>3 BUGG</td><td>07A</td><td>RVUE 0.0 p̄p → 3π<sup>0</sup></td></tr><tr><td>1449 ± 13</td><td>4.3k</td><td>4 GARMASH</td><td>06</td><td>BELL B<sup>+</sup> → K<sup>+</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1350 ± 50</td><td></td><td>ABLIKIM</td><td>05</td><td>BES2 J/ψ → φπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1265 ± 30<sup>+20</sup><sub>-35</sub></td><td></td><td>ABLIKIM</td><td>05Q</td><td>BES2 ψ(2S) → γπ<sup>+</sup>π<sup>-</sup> K<sup>+</sup> K<sup>-</sup></td></tr><tr><td>1434 ± 18</td><td>9</td><td>AITALA</td><td>01A</td><td>E791 π<sup>+</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1308 ± 10</td><td>848</td><td>BARBERIS</td><td>99b</td><td>OMEG 450 pp → p<sub>S</sub>ρf π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1315 ± 50</td><td></td><td>BELLAZZINI</td><td>99</td><td>GAM4 450 pp → pρπ<sup>0</sup>π<sup>0</sup></td></tr><tr><td>1315 ± 30</td><td></td><td>ALDE</td><td>98</td><td>GAM4 100 π<sup>-</sup> p → π<sup>0</sup>π<sup>0</sup> n</td></tr><tr><td>1280 ± 55</td><td></td><td>BERTIN</td><td>98</td><td>OBLX 0.05-0.405 πp → π<sup>+</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1186</td><td></td><td>5.6 TORNQVIST</td><td>95</td><td>RVUE ππ → ππ, K<sup>K</sup>, K<sup>K</sup>, ππ</td></tr><tr><td>1472 ± 12</td><td></td><td>ARMSTRONG</td><td>91</td><td>OMEG 300 pp → pρππ, pρK<sup>K</sup></td></tr><tr><td>1275 ± 20</td><td></td><td>BREAKSTONE</td><td>90</td><td>SFM 62 pp → pρπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1420 ± 20</td><td></td><td>AKESSON</td><td>86</td><td>SPEC 63 pp → pρπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>1256</td><td></td><td>FROGGATT</td><td>77</td><td>RVUE π<sup>+</sup>π<sup>-</sup> channel</td></tr></tbody></table>

1 Breit-Wigner mass.

2 Breit-Wigner mass. May also be the $f_0(1500)$.

3 Reanalysis of ABELE 96c data.

4 Also observed by GARMASH 07 in $B^0 \to K_0^S \pi^+\pi^-$ decays. Supersedes GARMASH 05.

5 Uses data from BEIER 72B, OCHS 73, HYAMS 73, GRAYER 74, ROSSELET 77, CA-SON 83, ASTON 88, and ARMSTRONG 91B. Coupled channel analysis with flavor symmetry and all light two-pseudoscalars systems.

6 Also observed by ASNER 00 in $\tau^- \to \pi^-\pi^0\pi^0\nu_\tau$ decays

K̄K MODE

<table><thead><tr><th>VALUE (MeV)</th><th>EVENTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5">• • • We do not use the following data for averages, fits, limits, etc. • • •</td></tr><tr><td>1422 ± 15 ± 28</td><td></td><td>1 AAJ</td><td>19H</td><td>LHCB p̄p → D<sup>±</sup>X</td></tr><tr><td>1360 ± 31 ± 28</td><td>430</td><td>2,3 DOBBS</td><td>15</td><td>J/ψ → γK<sup>+</sup>K<sup>-</sup></td></tr><tr><td>1350 ± 48 ± 15</td><td>168</td><td>2,3 DOBBS</td><td>15</td><td>ψ(2S) → γK<sup>+</sup>K<sup>-</sup></td></tr><tr><td>1440 ± 6</td><td></td><td>VLADIMIRSK...06</td><td>SPEC</td><td>40 π<sup>-</sup> p → K<sup>0</sup>S K<sup>0</sup>S n</td></tr><tr><td>1391 ± 10</td><td></td><td>TIKHOMIROV 03</td><td>SPEC</td><td>40.0 π<sup>-</sup> C → K<sup>0</sup>S K<sup>0</sup>S K<sup>0</sup>L X</td></tr><tr><td>1440 ± 50</td><td></td><td>BOLONKIN</td><td>88</td><td>SPEC 40 π<sup>-</sup> p → K<sup>0</sup>S K<sup>0</sup>S K<sup>0</sup>S n</td></tr><tr><td>1463 ± 9</td><td></td><td>ETKIN</td><td>82b</td><td>MPS 23 π<sup>-</sup> p → n2K<sup>0</sup>S</td></tr><tr><td>1425 ± 15</td><td></td><td>WICKLUND</td><td>80</td><td>SPEC 6 πN → K<sup>+</sup>K<sup>-</sup>N</td></tr><tr><td>~ 1300</td><td></td><td>POLYCHRO...</td><td>79</td><td>STRC 7 π<sup>-</sup> p → n2K<sup>0</sup>S</td></tr></tbody></table>

1 From the $D^± \to K^±K^+K^-$ Dalitz plot fit with the isobar model A.

2 Using CLEO-c data but not authored by the CLEO Collaboration.

3 From a fit to a Breit-Wigner shape with fixed $\Gamma = 346$ MeV.

4π MODE 2(ππ)<sub>S</sub>+ρρ

<table><thead><tr><th>VALUE (MeV)</th><th>EVENTS</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td colspan="5">• • • We do not use the following data for averages, fits, limits, etc. • • •</td></tr><tr><td>1395 ± 40</td><td></td><td>ABELE</td><td>01</td><td>CBAR 0.0 p̄p → π<sup>-</sup>4πp</td></tr><tr><td>1374 ± 38</td><td></td><td>AMSLER</td><td>94</td><td>CBAR 0.0 p̄p → π<sup>+</sup>π<sup>-</sup>3π<sup>0</sup></td></tr><tr><td>1345 ± 12</td><td></td><td>ADAMO</td><td>92</td><td>OBLX p̄p → 3π<sup>+</sup>2π<sup>-</sup></td></tr><tr><td>1386 ± 30</td><td></td><td>GASPERO</td><td>93</td><td>DBC 0.0 p̄p → 2π<sup>+</sup>3π<sup>-</sup></td></tr><tr><td>~ 1410</td><td>5751</td><td>1 BETTINI</td><td>66</td><td>DBC 0.0 p̄p → 2π<sup>+</sup>3π<sup>-</sup></td></tr></tbody></table>

1 ρρ dominant.

ηη MODE

<table><thead><tr><th>VALUE (MeV)</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead><tbody><tr><td>1262<sup>+51</sup><sub>-78</sub> ± 82</td><td>1 UEHARA</td><td>10A</td><td>BELL 10.6 e<sup>+</sup> e<sup>-</sup> → e<sup>+</sup> e<sup>-</sup>ηη</td></tr><tr><td>1430</td><td></td><td>AMSLER</td><td>92</td><td>CBAR 0.0 p̄p → π<sup>0</sup>ηη</td></tr><tr><td>1220 ± 40</td><td></td><td>ALDE</td><td>86D</td><td>GAM4 100 π<sup>-</sup> p → n2ηη</td></tr></tbody></table>

1 Breit-Wigner mass. May also be the $f_0(1500)$.
$$\Gamma(\pi^{+} \pi^{-} 2\pi^{0})/\Gamma(4\pi)$$

$$\Gamma_5/\Gamma_2 = \Gamma_5/(\Gamma_3+\Gamma_4+\Gamma_5)$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.512±0.019 1 GASPERO 93 DBC 0.0 $\bar{p}n$ → hadrons

¹ Model-dependent evaluation.

$$\Gamma(\rho\rho)/\Gamma(4\pi)$$

$$\Gamma_6/\Gamma_2$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.26±0.07 ABELE 01b CBAR 0.0 $\bar{p}d$ → $5\pi p$

$$\Gamma(2(\pi\pi)S-wave)/\Gamma(\pi\pi)$$

$$\Gamma_7/\Gamma_1$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

5.6±2.6 1 ABELE 01 CBAR 0.0 $\bar{p}d$ → $\pi^{-} 4\pi^{0} p$

¹ From the combined data of ABELE 96 and ABELE 96c.

$$\Gamma(2(\pi\pi)S-wave)/\Gamma(4\pi)$$

$$\Gamma_7/\Gamma_2$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.51±0.09 ABELE 01b CBAR 0.0 $\bar{p}d$ → $5\pi p$

$$\Gamma(\rho\rho)/\Gamma(2(\pi\pi)S-wave)$$

$$\Gamma_6/\Gamma_7$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>large</td><td>BARBERIS 00c</td><td>450 $pp \rightarrow p\bar{p} 4\pi p\bar{s}$</td></tr><tr><td>1.6 ±0.2</td><td>AMSLER 94</td><td>$\bar{p}p \rightarrow \pi^{+} \pi^{-} 3\pi^{0}$</td></tr><tr><td>~ 0.65</td><td>GASPERO 93</td><td>DBC 0.0 $\bar{p}n$ → hadrons</td></tr></tbody></table>

$$\Gamma(\pi(1300)\pi)/\Gamma(4\pi)$$

$$\Gamma_8/\Gamma_2$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.17±0.06 ABELE 01b CBAR 0.0 $\bar{p}d$ → $5\pi p$

$$\Gamma(\alpha_1(1260)\pi)/\Gamma(4\pi)$$

$$\Gamma_9/\Gamma_2$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.06±0.02 ABELE 01b CBAR 0.0 $\bar{p}d$ → $5\pi p$

$$\Gamma(\eta\eta)/\Gamma(4\pi)$$

$$\Gamma_{10}/\Gamma_2 = \Gamma_{10}/(\Gamma_3+\Gamma_4+\Gamma_5)$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>(28 ±11 ) × 10<sup>-3</sup></td><td>1 ANISOVICH 02d</td><td>SPEC Combined fit</td></tr><tr><td>( 4.7 ± 2.0 ) × 10<sup>-3</sup></td><td>BARBERIS 00e</td><td>450 $pp \rightarrow p\bar{p} \eta\eta\rho_S$</td></tr></tbody></table>

¹ From a combined K-matrix analysis of Crystal Barrel (0. $p\bar{p}$ → $\pi^{0}\pi^{0}\pi^{0}$, $\pi^{0}\eta\eta$, $\pi^{0}\pi^{0}\eta$), GAMS ($\pi p \rightarrow \pi^{0}\pi^{0} n$, $\eta\eta n$, $\eta\eta' n$), and BNL ($\pi p \rightarrow K\bar{K} n$) data.

$$\Gamma(K\bar{K})/\Gamma_{\text{total}}$$

$$\Gamma_{11}/\Gamma$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

0.35±0.13 BUGG 96 RVUE

$$\Gamma(K\bar{K})/\Gamma(\pi\pi)$$

$$\Gamma_{11}/\Gamma_1$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><tbody><tr><td>0.08±0.08</td><td>ABLIKIM 05</td><td>BES2 $J/\psi \rightarrow \phi^{+}\pi^{-}$, $\phi K^{+} K^{-}$</td></tr><tr><td>0.91±0.20</td><td>1 BARGIOTTI 03</td><td>OBLX $\bar{p}p$</td></tr><tr><td>0.12±0.06</td><td>2 ANISOVICH 02d</td><td>SPEC Combined fit</td></tr><tr><td>0.46±0.15±0.11</td><td>BARBERIS 99d</td><td>OMEG 450 $pp \rightarrow K^{+} K^{-}$, $\pi^{+} \pi^{-}$</td></tr></tbody></table>

¹ Coupled channel analysis of $\pi^{+} \pi^{-} \pi^{0}$, $K^{+} K^{-} \pi^{0}$, and $K^{+} K^{0} \pi^{\mp}$.

² From a combined K-matrix analysis of Crystal Barrel (0. $p\bar{p}$ → $\pi^{0}\pi^{0}\pi^{0}$, $\pi^{0}\eta\eta$, $\pi^{0}\pi^{0}\eta$), GAMS ($\pi p \rightarrow \pi^{0}\pi^{0} n$, $\eta\eta n$, $\eta\eta' n$), and BNL ($\pi p \rightarrow K\bar{K} n$) data.

$$\Gamma(K\bar{K}n\pi)/\Gamma_{\text{total}}$$

$$\Gamma_{12}/\Gamma$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<0.03 GASPERO 93 DBC 0.0 $\bar{p}n$ → hadrons

$$\Gamma(\beta\pi)/\Gamma_{\text{total}}$$

$$\Gamma_{13}/\Gamma$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<0.22 GASPERO 93 DBC 0.0 $\bar{p}n$ → hadrons

$$\Gamma(\omega\omega)/\Gamma_{\text{total}}$$

$$\Gamma_{14}/\Gamma$$

<table><thead><tr><th>VALUE</th><th>DOCUMENT ID</th><th>TECN</th><th>COMMENT</th></tr></thead></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<0.13 GASPERO 93 DBC 0.0 $\bar{p}n$ → hadrons

## $f_0(1370)$ REFERENCES

<table><tbody><tr><td>PELAEZ</td><td>23</td><td>PRL 130 051902</td><td>J.R. Pelaez, A. Rodas, J. Ruiz de Elvira (MADU+)</td></tr><tr><td>ALBRECHT</td><td>20</td><td>EPJ C80 453</td><td>A.V. Sarantsev et al. (BONN, PNPI)</td></tr><tr><td>AAIJ</td><td>19H</td><td>JHEP 1904 063</td><td>M. Albrecht et al. (Crystal Barrel Collab.)</td></tr><tr><td>AOUGE</td><td>18</td><td>PR D98 056021</td><td>R. Aaij et al. (LHCb Collab.)</td></tr><tr><td>DOBBS</td><td>15</td><td>PR D91 052006</td><td>S. Dobbs et al. (NWES)</td></tr><tr><td>OCHS</td><td>13</td><td>JP G40 043001</td><td>W. Ochs</td></tr><tr><td>UEHARA</td><td>10A</td><td>PR D82 114031</td><td>S. Uehara et al. (BELLE Collab.)</td></tr><tr><td>ANISOVICH</td><td>09</td><td>IMPJ A24 2481</td><td>V.V. Anisovich, A.V. Sarantsev (PNPI)</td></tr><tr><td>AUBERT</td><td>09L</td><td>PR D79 072006</td><td>B. Aubert et al. (BABAR Collab.)</td></tr><tr><td>PDG</td><td>08</td><td>(PDG Collab.) 1</td><td>S. Amsler et al. (BELLE Collab.)</td></tr><tr><td>UEHARA</td><td>08A</td><td>PR D78 052004</td><td>S. Uehara et al. (BELLE Collab.)</td></tr><tr><td>BONVICINI</td><td>07</td><td>PR D76 012001</td><td>G. Bonvicini et al. (CLEO Collab.)</td></tr><tr><td>BUGG</td><td>07A</td><td>JP G34 151</td><td>D.V. Bugg et al. (BELLE Collab.)</td></tr><tr><td>GARMASH</td><td>07</td><td>PR D75 012006</td><td>A. Garmash et al. (BELLE Collab.)</td></tr><tr><td>GARMASH</td><td>06</td><td>PR D96 251803</td><td>A. Garmash et al. (BELLE Collab.)</td></tr><tr><td>PDG</td><td>06</td><td>JP G33 1</td><td>W.-M. Yao et al. (PDG Collab.)</td></tr><tr><td>VLADIMIRSKY...</td><td>06</td><td>PAN 69 493</td><td>V.V. Vladimirskey et al. (ITEP, Moscow)</td></tr><tr><td>ABLIKIM</td><td>05</td><td>PL B607 243</td><td>Translated from YAF 69 515 (BES Collab.)</td></tr><tr><td>ABLIKIM</td><td>05Q</td><td>PL B607 092002</td><td>M. Ablikim et al. (BES Collab.)</td></tr><tr><td>GARMASH</td><td>05</td><td>PR D71 092003</td><td>A. Garmash et al. (BELLE Collab.)</td></tr><tr><td>ANISOVICH</td><td>03</td><td>EPJ A16 229</td><td>V.V. Anisovich et al. (BELLE Collab.)</td></tr><tr><td>BARGIOTTI</td><td>03</td><td>EPJ C26 371</td><td>M. Bargiotti et al. (OBELIX Collab.)</td></tr><tr><td>TIKHIOMIROV</td><td>03</td><td>PAN 66 828</td><td>G.D. Tikhomirov et al. (OBELIX Collab.)</td></tr><tr><td>ANISOVICH</td><td>02D</td><td>PAN 66 1545</td><td>V.V. Anisovich et al. (OBELIX Collab.)</td></tr><tr><td>ABELE</td><td>01</td><td>EPJ C19 667</td><td>Translated from YAF 65 1583 (Crystal Barrel Collab.)</td></tr><tr><td>ABELE</td><td>01B</td><td>EPJ C21 261</td><td>A. Abele et al. (Crystal Barrel Collab.)</td></tr><tr><td>ALTALA</td><td>01B</td><td>PR B86 755</td><td>E.M. Altala et al. (FNAL E791 Collab.) (BES Collab.)</td></tr><tr><td>ASNER</td><td>00</td><td>PR D61 012002</td><td>D. Asner et al. (CLEO Collab.)</td></tr><tr><td>BARBERIS</td><td>00C</td><td>PL B471 440</td><td>D. Barberis et al. (WA 102 Collab.)</td></tr><tr><td>BARBERIS</td><td>00E</td><td>PL B479 59</td><td>D. Barberis et al. (WA 102 Collab.)</td></tr><tr><td>BARBERIS</td><td>99B</td><td>PL B453 316</td><td>D. Barberis et al. (Omega Ext.)</td></tr><tr><td>BARBERIS</td><td>99D</td><td>PL B462 462</td><td>D. Barberis et al. (Omega Ext.)</td></tr><tr><td>BELLAZZINI</td><td>99</td><td>PL B467 296</td><td>R. Bellazzini et al. (Crystal Barrel Collab.)</td></tr><tr><td>KAMINSKI</td><td>99</td><td>EPJ C9 141</td><td>R. Kaminski, L. Lesniak, B. Loiseau (CRAC, PARIN)</td></tr><tr><td>ALDE</td><td>98</td><td>EPJ A3 361</td><td>D. Alde et al. (GAM4 Collab.)</td></tr><tr><td>Also</td><td>98</td><td>PAN 62 405</td><td>D. Alde et al. (GAMS Collab.)</td></tr><tr><td>ANISOVICH</td><td>98B</td><td>SPU B41 419</td><td>V.V. Anisovich et al. (OBELIX Collab.)</td></tr><tr><td>BERTIN</td><td>98</td><td>PR D57 55</td><td>A. Bertin et al. (OBELIX Collab.)</td></tr><tr><td>BARBERIS</td><td>97B</td><td>PR B413 217</td><td>D. Barberis et al. (OBELIX Collab.)</td></tr><tr><td>BERTIN</td><td>97C</td><td>PL B408 476</td><td>A. Bertin et al. (OBELIX Collab.)</td></tr><tr><td>ABELE</td><td>96</td><td>PL B380 453</td><td>A. Abele et al. (Crystal Barrel Collab.)</td></tr><tr><td>ABELE</td><td>96B</td><td>PL B385 425</td><td>A. Abele et al. (Crystal Barrel Collab.)</td></tr><tr><td>ABELE</td><td>96C</td><td>NP A609 562</td><td>A. Abele et al. (OBELIX Collab.)</td></tr><tr><td>BUGG</td><td>95B</td><td>NP B471 59</td><td>D.V. Bugg, A.V. Sarantsev, B.S. Zou (LOQM, PNPI)</td></tr><tr><td>AMSLER</td><td>95B</td><td>PL B342 433</td><td>C. Amsler et al. (Crystal Barrel Collab.)</td></tr><tr><td>AMSLER</td><td>95C</td><td>PL B353 571</td><td>C. Amsler et al. (Crystal Barrel Collab.)</td></tr><tr><td>AMSLER</td><td>95D</td><td>PL B355 425</td><td>C. Amsler et al. (Crystal Barrel Collab.)</td></tr><tr><td>JANSSEN</td><td>95</td><td>PR D52 2690</td><td>G. Janssen et al. (STON, ADLD, JULI)</td></tr><tr><td>TORNVIST</td><td>95</td><td>ZPHY C68 647</td><td>N.A. Tornqvist (HELS)</td></tr><tr><td>AMSLER</td><td>94</td><td>PL B322 431</td><td>C. Amsler et al. (Crystal Barrel Collab.) JPC</td></tr><tr><td>AMSLER</td><td>94D</td><td>PL B333 277</td><td>C. Amsler et al. (Crystal Barrel Collab.) JPC</td></tr><tr><td>ANISOVICH</td><td>94</td><td>PL B323 233</td><td>V.V. Anisovich et al. (LOQM)</td></tr><tr><td>BUGG</td><td>94</td><td>PR D50 4412</td><td>D. Bugg et al. (CRAC+)</td></tr><tr><td>KAMINSKI</td><td>94</td><td>PR D50 3145</td><td>A. Adamo et al. (OBELIX Collab.) JPC</td></tr><tr><td>ADAMO</td><td>93</td><td>NP A558 130C</td><td>M. Gaspero (ROMAI) JPC</td></tr><tr><td>GASPERO</td><td>94</td><td>NP A562 407</td><td>C. Amsler et al. (OBELIX Collab.) JPC</td></tr><tr><td>AMSLER</td><td>92</td><td>PL B291 347</td><td>V.V. Anisovich et al. (OBELIX Collab.) JPC</td></tr><tr><td>ARMSTRONG</td><td>91</td><td>ZPHY C51 351</td><td>T.A. Armstrong et al. (ATHU, BARI, BIRM+)</td></tr><tr><td>ARMSTRONG</td><td>91B</td><td>ZPHY C52 389</td><td>T.A. Armstrong et al. (ATHU, BARI, BIRM+)</td></tr><tr><td>BREAKSTONE</td><td>90</td><td>PL B67 67</td><td>A.M. Breakstone et al. (ISU, BGNA, CERN+)</td></tr><tr><td>MORGAN</td><td>90</td><td>ZPHY C48 569</td><td>D. Morgan, M.R. Pennington (RAL, DURH)</td></tr><tr><td>ASTON</td><td>88</td><td>NP B296 493</td><td>D. Aston et al. (SLAC, NAGO, CINC, INUS)</td></tr><tr><td>BOLONKIN</td><td>88</td><td>NP B309 426</td><td>B.V. Bolonkin et al. (ITEP, SERP)</td></tr><tr><td>FALVARD</td><td>88</td><td>PR D38 2706</td><td>A. Falvard et al. (CLER, FRAS, LALO+)</td></tr><tr><td>VORobyev</td><td>88</td><td>SJNP 48 273</td><td>P.V. Vorobyev et al. (NOVO)</td></tr><tr><td>Also</td><td>88</td><td>Translated from YAF 48 446</td><td>K.L. Au, D. Morgan, M.R. Pennington (DURH, RAL)</td></tr><tr><td>AU</td><td>87</td><td>PR D35 1633</td><td>T. Akesson et al. (Axial Field Spec.) (DURH, RAL)</td></tr><tr><td>AKESON</td><td>86</td><td>NP B264 154</td><td>D. Akesson et al. (Axial Field Spec.) (DURH, RAL)</td></tr><tr><td>ALDE</td><td>86D</td><td>NP B269 485</td><td>D.M. Ame et al. (BELG, LAPP, SERP, CERN+)</td></tr><tr><td>LONGACRE</td><td>86</td><td>NP B177 223</td><td>R.S. Longacre et al. (BNL, BRAN, CUNY+)</td></tr><tr><td>BINON</td><td>84C</td><td>NC 40A 363</td><td>F.G. Binon et al. (BELG, LAPP, SERP+)</td></tr><tr><td>BINON</td><td>83</td><td>NC 78A 313</td><td>F.G. Binon et al. (BELG, LAPP, SERP+)</td></tr><tr><td>CASON</td><td>83</td><td>PR D28 1586</td><td>N.M. Cason et al. (NDAM, ANL)</td></tr><tr><td>ETKIN</td><td>82B</td><td>PR D25 1786</td><td>A. Etkin et al. (BNL, CUNY, TUFTS, VAND)</td></tr><tr><td>WICKLUND</td><td>80</td><td>PR 45 1469</td><td>A.B. Wicklund et al. (ANL)</td></tr><tr><td>BECKER</td><td>79</td><td>NP B67 46</td><td>H. Becker et al. (MPIM, CERN, ZEEM, CRAC)</td></tr><tr><td>POLYCHRO...</td><td>79</td><td>PR D19 1317</td><td>V.A. Polychronakos et al. (NDAM, ANL)</td></tr><tr><td>FROGGATT</td><td>77</td><td>NP B129 89</td><td>C.D. Froggatt, J.L. Petersen (GLAS, NORD)</td></tr><tr><td>ROSSELET</td><td>77</td><td>PR D15 574</td><td>L. Rosselet et al. (GEVA, SACL)</td></tr><tr><td>HYAMS</td><td>75</td><td>NP B100 205</td><td>B.D. Hyams et al. (CERN, MPIM)</td></tr><tr><td>GRAYER</td><td>74</td><td>NP B17 189</td><td>G. Gruer et al. (CERN, MPIM)</td></tr><tr><td>HYAMS</td><td>73</td><td>NP B64 134</td><td>B.D. Hyams et al. (CERN, MPIM)</td></tr><tr><td>OCHS</td><td>73</td><td>Thesis</td><td>W. Ochs</td></tr><tr><td>BEIER</td><td>72B</td><td>PRL 29 511</td><td>E.W. Beier et al. (PENN)</td></tr><tr><td>BETTINI</td><td>66</td><td>NC 42A 695</td><td>A. Bettini et al. (PADO, PISA)</td></tr></tbody></table>

$$\pi_1(1400)$$

$$\Gamma^{G}(JPC) = 1^{-}(1^{+})$$

## OMITTED FROM SUMMARY TABLE

Coupled channel analyses favor the existence of only one broad $1^{-}$ isovector state consistent with $\pi_1(1600)$ in the 1400–1600 MeV region. See the review on "Spectroscopy of Light Meson Resonances". See also $\pi_1(1600)$.
# Meson Particle Listings

η(1405)

$\eta(1405)$

$I^G(J^{PC}) = 0^+(0^- +)$

See also the η(1475).

## η(1405) MASS

VALUE (MeV)

DOCUMENT ID

**1408.7<sup>+2.0</sup><sub>-1.2</sub> OUR AVERAGE** Includes data from the 2 datablocks that follow this one.

Error includes scale factor of 2.2. See the ideogram below.

<figure><img src="image_461.png" /><figcaption>η(1405) mass (MeV)</figcaption></figure>

## ηππ MODE

VALUE (MeV)

EVTS

DOCUMENT ID

TECN

COMMENT

The data in this block is included in the average printed for a previous datablock.

**1405.8± 2.6 OUR AVERAGE** Error includes scale factor of 2.3. See the ideogram below.

1409.0± 1.7 743 ABLIKIM 12E BES3 $J/\psi \rightarrow \gamma(\pi^{+}\pi^{-}\pi^{0})$
1407.0± 3.5 198 ABLIKIM 12E BES3 $J/\psi \rightarrow \gamma(\pi^{0}\pi^{0}\pi^{0})$
1399.8± 2.2<sup>+2.8</sup><sub>-0.1</sub> 1 ABLIKIM 11J BES3 $J/\psi \rightarrow \omega(\eta\pi^{+}\pi^{-})$
1392 ±14 900 ±375 AMSLER 04B CBAR $0 p\bar{p} \rightarrow \pi^{+}\pi^{-}\pi^{+}\pi^{-}\eta$
1394 ± 8 6.6 ±2.0k AMSLER 04B CBAR $0 p\bar{p} \rightarrow \pi^{+}\pi^{-}\pi^{0}\pi^{0}\eta$
1404 ± 6 9082 MANAK 00a MPS 18 π⁻p → ηπ⁺π⁻n
1424 ± 6 2200 ALDE 97B GAM4 100 π⁻p → ηπ⁺π⁻n
1400 ± 6 2 BOLTON 92B MRK3 $J/\psi \rightarrow \gamma\eta\pi^{+}\pi^{-}$
1388 ± 4 FUKUI 91C SPEC 8.95 π⁻p → ηπ⁺π⁻n
1398 ± 6 261 3 AUGUSTIN 90 DM2 $J/\psi \rightarrow \gamma\eta\pi^{+}\pi^{-}$
1420 ± 5 ANDO 86 SPEC 8 π⁻p → ηπ⁺π⁻n

● ● ● We do not use the following data for averages, fits, limits, etc. ● ● ●

1404.0±11.0 195 ABLIKIM 19B BES3 $e^{+}e^{-} \rightarrow \psi(2S)$
1385 ± 7 BAI 99 BES $J/\psi \rightarrow \gamma\eta\pi^{+}\pi^{-}$
1409 ± 3 4 AMSLER 95F CBAR $0 p\bar{p} \rightarrow \pi^{+}\pi^{-}\pi^{0}\pi^{0}\eta$

¹ The selected process is $J/\psi \rightarrow \omega\alpha_0(980)\pi$.

² From fit to the $\alpha_0(980)\pi^0 -$ partial wave.

³ Best fit with a single Breit Wigner.

⁴ Superseded by AMSLER 04B.

<figure><img src="image_462.png" /><figcaption>η(1405) mass, ηππ mode (MeV)</figcaption></figure>

## $K\bar{K}\pi$ MODE ($\alpha_0(980)\pi$ or direct $K\bar{K}\pi$)

VALUE (MeV)

EVTS

DOCUMENT ID

TECN

COMMENT

The data in this block is included in the average printed for a previous datablock.

**1413.5<sup>+2.0</sup><sub>-0.9</sub> OUR AVERAGE** Error includes scale factor of 1.3. See the ideogram below.

1391.7± 0.7<sup>+11.3</sup><sub>-0.3</sub> 126k 1 ABLIKIM 23M BES3 $J/\psi \rightarrow \gamma K_S^0 K_S^0 \pi^0$
1413 ±14 3651 2 NICHITIU 02 OBLX $0 p\bar{p} \rightarrow K^+K^-\pi^+\pi^-\pi^0$
1416 ± 4 ± 2 20k ADAMS 01B B852 18 GeV π⁻p → K⁺K⁻π⁰n
1405 ± 5 3 CICALO 99 OBLX $0 p\bar{p} \rightarrow K^\pm K_S^0 K^\mp\pi^+\pi^-$
1407 ± 5 3 BERTIN 97 OBLX $0 p\bar{p} \rightarrow K^\pm(K_S^0)\pi^\mp\pi^+\pi^-$
1416 ± 2 3 BERTIN 95 OBLX $0 p\bar{p} \rightarrow K\bar{K}\pi\pi\pi$
1416 ± 8 <sup>+7</sup><sub>-5</sub> 700 4 BAI 90C MRK3 $J/\psi \rightarrow \gamma K_S^0 K^\pm\pi^\mp$
1413 ± 5 4 RATH 89 MPS 21.4 π⁻p → nK_S^0 K_S^0 π^0

● ● ● We do not use the following data for averages, fits, limits, etc. ● ● ●

1459 ± 5 5 AUGUSTIN 92 DM2 $J/\psi \rightarrow \gamma K\bar{K}\pi$

¹ ABLIKIM 23M reports for this state a significance from the fit much higher than 35 σ.

² Decaying dominantly directly to $K^+K^-\pi^0$.

³ Decaying into $(K\bar{K})_S\pi$, $(K\pi)_S K\bar{K}$, and $\alpha_0(980)\pi$.

⁴ From fit to the $\alpha_0(980)\pi^0 -$ partial wave. Cannot rule out a $\alpha_0(980)\pi^1$ ++ partial wave.

⁵ Excluded from averaging because averaging would be meaningless.

<figure><img src="image_463.png" /><figcaption>η(1405) mass, $K\bar{K}\pi$ mode ($\alpha_0(980)\pi$ dominant) (MeV)</figcaption></figure>

## ππγ MODE

VALUE (MeV)

EVTS

DOCUMENT ID

TECN

COMMENT

**1403±17 OUR AVERAGE** Error includes scale factor of 1.8.

1390±12 235 ± 91 AMSLER 04B CBAR $0 p\bar{p} \rightarrow \pi^{+}\pi^{-}\pi^{+}\pi^{-}\eta$
1424±10±11 547 BAI 04J BES2 $J/\psi \rightarrow \gamma\gamma\pi^{+}\pi^{-}$

● ● ● We do not use the following data for averages, fits, limits, etc. ● ● ●

1401±18 1,2 AUGUSTIN 90 DM2 $J/\psi \rightarrow \pi^{+}\pi^{-}\gamma\gamma$
1432± 8 2 COFFMAN 90 MRK3 $J/\psi \rightarrow \pi^{+}\pi^{-}2\gamma$

¹ Best fit with a single Breit Wigner.

² This peak in the $\gamma p$ channel may not be related to the $\eta(1405)$.

## 4π MODE

VALUE (MeV)

EVTS

DOCUMENT ID

TECN

COMMENT

● ● ● We do not use the following data for averages, fits, limits, etc. ● ● ●

1420±20 BUGG 95 MRK3 $J/\psi \rightarrow \gamma\pi^{+}\pi^{-}\pi^{+}\pi^{-}$
1489±12 3270 1 BISELLO 89B DM2 $J/\psi \rightarrow 4\pi\gamma$

¹ Estimated by us from various fits.

## $K\bar{K}\pi$ MODE (unresolved)

VALUE (MeV)

EVTS

DOCUMENT ID

TECN

COMMENT

● ● ● We do not use the following data for averages, fits, limits, etc. ● ● ●

1452.7± 3.3 191 1,2 ABLIKIM 13M BES3 $\psi(2S) \rightarrow \omega K K\pi$
1437.6± 3.2 249 ± 35 1,2 ABLIKIM 08E BES2 $J/\psi \rightarrow \omega K_S^0 K^+\pi^- + \text{c.c.}$
1445.9± 5.7 62 ± 18 1,2 ABLIKIM 08E BES2 $J/\psi \rightarrow \omega K^+ K^-\pi^0$
1442 ±10 410 1 BAI 98C BES $J/\psi \rightarrow \gamma K^+ K^-\pi^0$
1445 ± 8 693 1 AUGUSTIN 90 DM2 $J/\psi \rightarrow \gamma K_S^0 K^\pm\pi^\mp$
1433 ± 8 296 1 AUGUSTIN 90 DM2 $J/\psi \rightarrow \gamma K^+ K^-\pi^0$
1413 ± 8 500 1 DUCH 89 ASTE $p\bar{p} \rightarrow \pi^{+}\pi^{-}K^\mp\pi^\mp K^0$
1453 ± 7 170 1 RATH 89 MPS 21.4 π⁻p → K_S^0 K_S^0 π^0n
1419 ± 1 8800 1 BIRMAN 88 MPS 8 π⁻p → K^+K^-π^0n
1424 ± 3 620 1 REEVES 86 SPEC 6.6 p p\bar{p} → K\bar{K}\pi X
1421 ± 2 1 CHUNG 85 MPS 8 π⁻p → K\bar{K}\pi n
1440 <sup>+20</sup><sub>-15</sub> 174 1 EDWARDS 82E CBAL $J/\psi \rightarrow \gamma K^+ K^-\pi^0$
<table><tr><td>1440</td><td>+10/15</td><td>1 SCHARRE</td><td>80</td><td>MRK2</td><td>J/ψ → γK<sub>S</sub><sup>0</sup>K<sup>±</sup>π<sup>∓</sup></td></tr><tr><td>1425</td><td>±7</td><td>800</td><td>1,3 BAILLON</td><td>67</td><td>HBC 0 p p → K<sup>±</sup>Kπππ</td></tr></table>

¹ These experiments identify only one pseudoscalar in the 1400–1500 range. Data could also refer to $η(1475)$.

² Systematic uncertainty not evaluated.

³ From best fit of 0<sup>-</sup> + partial wave, 50% K*(892) K, 50% a₀(980) π.

η(1405) WIDTH

VALUE (MeV) DOCUMENT ID

**50.3±2.5 OUR AVERAGE** Includes data from the 2 datablocks that follow this one. Error includes scale factor of 1.6. See the ideogram below.

<figure><img src="image_464.png" /><figcaption>WEIGHTED AVERAGE
50.3±2.5 (Error scaled by 1.6)</figcaption></figure>

ηππ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN COMMENT

The data in this block is included in the average printed for a previous datablock.

**52.6±3.2 OUR AVERAGE** Error includes scale factor of 1.3. See the ideogram below.

<table><tr><td>48.3 ± 5.2</td><td>743</td><td>ABLIKIM</td><td>12E BES3</td><td>J/ψ → γ(π<sup>+</sup>π<sup>-</sup>π<sup>0</sup>)</td></tr><tr><td>55.0 ± 11.0</td><td>198</td><td>ABLIKIM</td><td>12E BES3</td><td>J/ψ → γ(π<sup>0</sup>π<sup>0</sup>π<sup>0</sup>)</td></tr><tr><td>52.8 ± 7.6<sup>+0.1</sup><sub>-7.6</sub></td><td></td><td>1 ABLIKIM</td><td>11J BES3</td><td>J/ψ → ω(ηπ<sup>+</sup>π<sup>-</sup>)</td></tr><tr><td>55 ± 11</td><td>900</td><td>AMSLER</td><td>04B CBAR</td><td>0 p p → π<sup>+</sup>π<sup>-</sup>π<sup>+</sup>π<sup>-</sup>η</td></tr><tr><td>55 ± 12</td><td>6.6k</td><td>AMSLER</td><td>04B CBAR</td><td>0 p p → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup>π<sup>0</sup>γ</td></tr><tr><td>80 ± 21</td><td>9.0k</td><td>MANAK</td><td>00A MPS</td><td>18 π<sup>-</sup> p → ηπ<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>85 ± 18</td><td>2.2k</td><td>ALDE</td><td>97B GAM4</td><td>100 π<sup>-</sup> p → ηπ<sup>0</sup>π<sup>0</sup>π<sup>0</sup>π<sup>0</sup></td></tr><tr><td>47 ± 13</td><td></td><td>2 BOLTON</td><td>92B MRK3</td><td>J/ψ → γηπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>59 ± 4</td><td></td><td>FUKUI</td><td>91C SPEC</td><td>8.95 π<sup>-</sup> p → ηπ<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>53 ± 11</td><td></td><td>3 AUGUSTIN</td><td>90 DM2</td><td>J/ψ → γηπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td>31 ± 7</td><td></td><td>ANDO</td><td>86 SPEC</td><td>8 π<sup>-</sup> p → ηπ<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr></table>

• • • We do not use the following data for averages, fits, limits, etc. • • •

<table><caption>WEIGHTED AVERAGE
52.6±3.2 (Error scaled by 1.3)</caption><tr><td>79.0 ± 16.0</td><td>195</td><td>ABLIKIM</td><td>19BA BES3</td><td>e<sup>+</sup>e<sup>-</sup> → ψ(2S)</td></tr><tr><td>86 ± 10</td><td></td><td>4 AMSLER</td><td>95F CBAR</td><td>0 p p → π<sup>+</sup>π<sup>-</sup>π<sup>0</sup>π<sup>0</sup>η</td></tr></table>

<figure><img src="image_465.png" /></figure>

¹ The selected process is J/ψ → ωa₀(980)π.

² From fit to the a₀(980)π 0<sup>-</sup> + partial wave.

³ From ηπ<sup>+</sup>π<sup>-</sup> mass distribution - mainly a₀(980)π - no spin-parity determination available.

⁴ Superseded by AMSLER 04B.

K̄Kπ MODE (a₀(980)π or direct K̄Kπ)

VALUE (MeV) EVTS DOCUMENT ID TECN COMMENT

The data in this block is included in the average printed for a previous datablock.

**49 ± 4 OUR AVERAGE** Error includes scale factor of 2.0. See the ideogram below.

<table><tr><td>60.8 ± 1.2<sup>+5.5</sup><sub>-12.0</sub></td><td>126K</td><td>ABLIKIM</td><td>23M BES3</td><td>J/ψ → γK<sub>S</sub><sup>0</sup>K<sup>±</sup>π<sup>0</sup></td></tr><tr><td>51 ± 6</td><td>3651</td><td>1 NICHITIU</td><td>02 OBLX</td><td>0 p p → K<sup>+</sup>K<sup>-</sup>π<sup>+</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>42 ± 10</td><td>± 9</td><td>ADAMS</td><td>01B B852</td><td>18 GeV π<sup>-</sup> p → K<sup>+</sup>K<sup>-</sup>π<sup>0</sup>π<sup>0</sup></td></tr><tr><td>50 ± 4</td><td></td><td>CICALO</td><td>99 OBLX</td><td>0 p p → K<sup>±</sup>K<sub>S</sub><sup>0</sup>π<sup>∓</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>48 ± 5</td><td></td><td>2 BERTIN</td><td>97 OBLX</td><td>0.0 p p → K<sup>±</sup>(K<sup>0</sup>)π<sup>+</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>50 ± 4</td><td></td><td>2 BERTIN</td><td>95 OBLX</td><td>0 p p → K̄Kπππ</td></tr><tr><td>75 ± 9</td><td></td><td>AUGUSTIN</td><td>92 DM2</td><td>J/ψ → γK̄Kπ</td></tr><tr><td>91 ± 67<sup>+15</sup><sub>-31</sub></td><td>± 15</td><td>3 BAI</td><td>90C MRK3</td><td>J/ψ → γK<sub>S</sub><sup>0</sup>K<sup>±</sup>π<sup>∓</sup></td></tr><tr><td>19 ± 7</td><td></td><td>3 RATH</td><td>89 MPS</td><td>21.4 π<sup>-</sup> p → nK<sub>S</sub><sup>0</sup>K<sup>0</sup>π<sup>0</sup></td></tr></table>

¹ Decaying dominantly directly to K<sup>+</sup>K<sup>-</sup>π<sup>0</sup>.

² Decaying into (K̄K)₅π, (Kπ)₅K̄, and a₀(980)π.

³ From fit to the a₀(980)π 0<sup>-</sup> + partial wave, but a₀(980)π 1<sup>++</sup> cannot be excluded.

<figure><img src="image_466.png" /><figcaption>η(1405) width K̄Kπ mode (a₀(980)π dominant) (MeV)</figcaption></figure>

ππγ MODE

VALUE (MeV) EVTS DOCUMENT ID TECN COMMENT

<table><tr><td>89 ±17</td><td>OUR AVERAGE</td><td>Error includes scale factor of 1.7.</td><td></td></tr><tr><td>64 ±18</td><td>235 ± 91</td><td>AMSLER</td><td>04B CBAR 0 p p → π<sup>+</sup>π<sup>-</sup>π<sup>+</sup>π<sup>-</sup>γ</td></tr><tr><td>101.0 ± 8.8 ± 8.8</td><td>547</td><td>BAI</td><td>04J BES2 J/ψ → γγπ<sup>+</sup>π<sup>-</sup></td></tr><tr><td colspan="4">• • • We do not use the following data for averages, fits, limits, etc. • • •</td></tr><tr><td>174 ±44</td><td></td><td>AUGUSTIN</td><td>90 DM2 J/ψ → π<sup>+</sup>π<sup>-</sup>γγ</td></tr><tr><td>90 ±26</td><td></td><td>1 COFFMAN</td><td>90 MRK3 J/ψ → π<sup>+</sup>π<sup>-</sup>2γ</td></tr></table>

¹ This peak in the γρ channel may not be related to the η(1405).

4π MODE

VALUE (MeV) EVTS DOCUMENT ID TECN COMMENT

<table><tr><td colspan="4">• • • We do not use the following data for averages, fits, limits, etc. • • •</td></tr><tr><td>160 ± 30</td><td></td><td>BUGG</td><td>95 MRK3</td><td>J/ψ → γπ<sup>+</sup>π<sup>-</sup>π<sup>+</sup>π<sup>-</sup></td></tr><tr><td>144 ± 13</td><td>3270</td><td>1 BISELLO</td><td>89B DM2</td><td>J/ψ → 4πγ</td></tr></table>

¹ Estimated by us from various fits.

K̄Kπ MODE (unresolved)

VALUE (MeV) EVTS DOCUMENT ID TECN COMMENT

<table><tr><td colspan="4">• • • We do not use the following data for averages, fits, limits, etc. • • •</td></tr><tr><td>45.9 ± 8.2</td><td>191</td><td>1,2 ABLIKIM</td><td>13M BES3 ψ(2S) → ωK̄Kπ</td></tr><tr><td>48.9 ± 9.0</td><td>249 ± 35</td><td>1,2 ABLIKIM</td><td>08E BES2 J/ψ → ωK<sub>S</sub><sup>0</sup>K<sup>+</sup>π<sup>-</sup> + c.c.</td></tr><tr><td>34.2 ± 18.5</td><td>62 ± 18</td><td>1,2 ABLIKIM</td><td>08E BES2 J/ψ → ωK<sup>+</sup>K<sup>-</sup>π<sup>0</sup></td></tr><tr><td>93 ± 14</td><td>296</td><td>1 AUGUSTIN</td><td>90 DM2 J/ψ → γK<sup>+</sup>K<sup>-</sup>π<sup>0</sup></td></tr><tr><td>105 ± 10</td><td>693</td><td>1 AUGUSTIN</td><td>90 DM2 J/ψ → γK<sub>S</sub><sup>0</sup>K<sup>±</sup>π<sup>∓</sup></td></tr><tr><td>62 ± 16</td><td>500</td><td>1 DUCH</td><td>89 ASTE p p → K̄Kπππ</td></tr><tr><td>100 ± 11</td><td>170</td><td>1 RATH</td><td>89 MPS 21.4 π<sup>-</sup> p → K<sup>0</sup>S K<sup>0</sup>π<sup>0</sup>π<sup>0</sup></td></tr><tr><td>66 ± 2</td><td>8800</td><td>1 BIRMAN</td><td>88 MPS 8 π<sup>-</sup> p → K<sup>+</sup>K̄K<sup>0</sup>π<sup>-</sup>π<sup>0</sup></td></tr><tr><td>60 ± 10</td><td>620</td><td>1 REEVES</td><td>86 SPEC 6.6 p p → K̄KπX</td></tr><tr><td>60 ± 10</td><td></td><td>1 CHUNG</td><td>85 SPEC 8 π<sup>-</sup> p → K̄Kππ</td></tr><tr><td>55 ± 20</td><td>174</td><td>1 EDWARDS</td><td>82E CBAL J/ψ → γK<sup>+</sup>K<sup>-</sup>π<sup>0</sup></td></tr><tr><td>50 ± 30</td><td></td><td>1 SCHARRE</td><td>80 MRK2 J/ψ → γK<sub>S</sub><sup>0</sup>K<sup>±</sup>π<sup>∓</sup></td></tr><tr><td>50 ± 20</td><td></td><td>1,3 BAILLON</td><td>67 HBC 0.0 p p → K̄Kπππ</td></tr><tr><td>80 ± 10</td><td>800</td><td></td><td></td></tr></table>

¹ These experiments identify only one pseudoscalar in the 1400–1500 range. Data could also refer to η(1475).

² Systematic uncertainty not evaluated.

³ From best fit to 0<sup>-</sup> + partial wave, 50% K*(892)K, 50% a₀(980)π.
## $\eta(1405)$ DECAY MODES

<table><thead><tr><th>Mode</th><th></th><th>Fraction ($\Gamma_i/\Gamma$)</th><th>Confidence level</th></tr></thead><tbody><tr><td>$\Gamma_1$</td><td>$K\bar{K}\pi$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_2$</td><td>$\eta\pi\pi$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_3$</td><td>$a_0(980)\pi$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_4$</td><td>$\eta(\pi\pi)S-wave$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_5$</td><td>$f_0(980)\pi^0 \to \pi^+\pi^-\pi^0$</td><td>not seen</td><td></td></tr><tr><td>$\Gamma_6$</td><td>$f_0(980)\eta$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_7$</td><td>$4\pi$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_8$</td><td>$\rho\rho$</td><td>&lt;58 %</td><td>99.85%</td></tr><tr><td>$\Gamma_9$</td><td>$\gamma\gamma$</td><td></td><td></td></tr><tr><td>$\Gamma_{10}$</td><td>$\rho^0\gamma$</td><td>seen</td><td></td></tr><tr><td>$\Gamma_{11}$</td><td>$\phi\gamma$</td><td></td><td></td></tr><tr><td>$\Gamma_{12}$</td><td>$K^*(892)K$</td><td>seen</td><td></td></tr></tbody></table>

## $\eta(1405)$ $\Gamma(i)\Gamma(\gamma\gamma)/\Gamma(\text{total})$

$$ \Gamma(K\bar{K}\pi) \times \Gamma(\gamma\gamma)/\Gamma_{\text{total}} \qquad \Gamma_1\Gamma_9/\Gamma $$

$$ \begin{array}{l} \text{VALUE (keV)} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ <0.035 \quad 90 \quad 1,2 \text{ AHOHE} \quad 05 \quad \text{CLE2} \quad 10.6 e^+ e^- \to e^+ e^- K_S^0 K^\pm \pi^\mp $$

¹ Using $\eta(1405)$ mass and width 1410 MeV and 51 MeV, respectively.

² Assuming three-body phase-space decay to $K_S^0 K^\pm \pi^\mp$.

$$ \Gamma(\eta\pi\pi) \times \Gamma(\gamma\gamma)/\Gamma_{\text{total}} \qquad \Gamma_2\Gamma_9/\Gamma $$

$$ \begin{array}{l} \text{VALUE (keV)} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \end{array} $$

$$ <0.095 \quad 95 \quad \text{ACCIARRI} \quad 01G \quad L3 \quad 183-202 \ e^+ e^- \to e^+ e^- \eta\pi^+ \pi^- $$

$$ \Gamma(\rho^0\gamma) \times \Gamma(\gamma\gamma)/\Gamma_{\text{total}} \qquad \Gamma_{10}\Gamma_9/\Gamma $$

$$ \begin{array}{l} \text{VALUE (keV)} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ <1.5 \quad 95 \quad \text{ALTHOFF} \quad 84E \quad \text{TASS} \quad e^+ e^- \to e^+ e^- \pi^+ \pi^- \gamma $$

## $\eta(1405)$ BRANCHING RATIOS

$$ \Gamma(\eta\pi\pi)/\Gamma(K\bar{K}\pi) \qquad \Gamma_2/\Gamma_1 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ \text{1.09}\pm0.48 \quad 1 \quad \text{AMSLER} \quad 04B \quad \text{CBAR} \quad 0 \bar{p} p \to \pi^+\pi^-\pi^+\pi^-\eta \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ <0.5 \quad 90 \quad \text{EDWARDS} \quad 83B \quad \text{CBAL} \quad J/\psi \to \eta\pi\pi\gamma $$

$$ <1.1 \quad 90 \quad \text{SCHARRE} \quad 80 \quad \text{MRK2} \quad J/\psi \to \eta\pi\pi\gamma $$

$$ <1.5 \quad 95 \quad \text{FOSTER} \quad 68B \quad \text{HBC} \quad 0.0 \bar{p} p \to K K \pi X $$

¹ Using the data of BAILLON 67 on $\bar{p}p \to K\bar{K}\pi$.

$$ \Gamma(\rho^0\gamma)/\Gamma(\eta\pi\pi) \qquad \Gamma_{10}/\Gamma_2 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ \text{0.111}\pm0.064 \quad 1 \quad \text{AMSLER} \quad 04B \quad \text{CBAR} \quad 0 \bar{p} p \to K\bar{K}\pi\pi \end{array} $$

$$ \Gamma(a_0(980)\pi)/\Gamma(K\bar{K}\pi) \qquad \Gamma_3/\Gamma_1 $$

$$ \begin{array}{l} \text{VALUE (keV)} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ \sim 0.15 \quad 1 \quad \text{BERTIN} \quad 95 \quad \text{OBL} \quad 0 \bar{p} p \to K\bar{K}\pi\pi\pi $$

$$ \sim 0.8 \quad 500 \quad 1 \quad \text{DUCH} \quad 89 \quad \text{ASTE} \quad \bar{p} p \to \pi^+\pi^- K^\pm \pi^+ K^0 $$

$$ \sim 0.75 \quad 1 \quad \text{REEVES} \quad 86 \quad \text{SPEC} \quad 6.6 p \bar{p} \to K K \pi X $$

¹ Assuming that the $a_0(980)$ decays only into $K\bar{K}$.

$$ \Gamma(a_0(980)\pi)/\Gamma(\eta\pi\pi) \qquad \Gamma_3/\Gamma_2 $$

$$ \begin{array}{l} \text{VALUE (keV)} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ 0.29\pm0.10 \quad \text{ABELE} \quad 98E \quad \text{CBAR} \quad 0 p \bar{p} \to \eta\pi^0\pi^0\pi^0 $$

$$ 0.15\pm0.04 \quad 2200 \quad 1 \quad \text{ALDE} \quad 97B \quad \text{GAM4} \quad 100 \pi^- p \to \eta\pi^0\pi^0\eta $$

$$ 0.56\pm0.04\pm0.03 \quad 1 \quad \text{AMSLER} \quad 95F \quad \text{CBAR} \quad 0 \bar{p} p \to \pi^+\pi^-\pi^0\pi^0\eta $$

¹ Assuming that the $a_0(980)$ decays only into $\eta\pi$.

$$ \Gamma(a_0(980)\pi)/\Gamma(\eta(\pi\pi)S-wave) \qquad \Gamma_3/\Gamma_4 $$

$$ \begin{array}{l} \text{VALUE (keV)} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ 0.91\pm0.12 \quad \text{ANISOVICH} \quad 01 \quad \text{SPEC} \quad 0.0 \bar{p} p \to \eta\pi^+\pi^-\pi^+\pi^-\pi^- $$

$$ 0.15\pm0.04 \quad 9082 \quad 1 \quad \text{MANAK} \quad 00A \quad \text{MPS} \quad 18 \pi^- p \to \eta\pi^+\pi^-\pi^-\pi^- $$

$$ 0.70\pm0.12\pm0.20 \quad 2 \quad \text{BAI} \quad 99 \quad \text{BES} \quad J/\psi \to \gamma\eta\pi^+\pi^- $$

¹ Statistical error only.

² Assuming that the $a_0(980)$ decays only into $\eta\pi$.

$$ \Gamma(\rho^0\gamma)/\Gamma(K\bar{K}\pi) \qquad \Gamma_{10}/\Gamma_1 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ \text{0.0152}\pm0.0038 \quad 1 \quad \text{COFFMAN} \quad 90 \quad \text{MRK3} \quad J/\psi \to \gamma\gamma\pi^+\pi^- \end{array} $$

¹ Using $B(J/\psi \to \gamma\eta(1405) \to \gamma K\bar{K}\pi) = 4.2 \times 10^{-3}$ and $B(J/\psi \to \gamma\eta(1405) \to \gamma\gamma\rho^0) = 6.4 \times 10^{-5}$.

$$ \Gamma(\gamma\gamma)/\Gamma(K\bar{K}\pi) \qquad \Gamma_9/\Gamma_1 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ <1.78 \times 10^{-3} \quad 90 \quad 1 \quad \text{ABLIKIM} \quad 180 \quad \text{BES3} \quad \psi(2S) \to \pi^+\pi^-\gamma\gamma\gamma \end{array} $$

¹ Using results from BAI 00D.

$$ \Gamma(\eta(\pi\pi)S-wave)/\Gamma(\eta\pi\pi) \qquad \Gamma_4/\Gamma_2 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ 0.81\pm0.04 \quad 2200 \quad \text{ALDE} \quad 97B \quad \text{GAM4} \quad 100 \pi^- p \to \eta\pi^0\pi^0\eta \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

$$ \Gamma(f_0(980)\eta)/\Gamma(\eta\pi\pi) \qquad \Gamma_6/\Gamma_2 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ 0.32\pm0.07 \quad 1 \quad \text{ANISOVICH} \quad 00 \quad \text{SPEC} \quad 0.9-1.2 \bar{p} p \to \eta\pi^3\eta \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

¹ Using preliminary Crystal Barrel data.

$$ \Gamma(f_0(980)\pi^0 \to \pi^+\pi^-\pi^0)/\Gamma_{\text{total}} \qquad \Gamma_5/\Gamma $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ \text{not seen} \quad 1 \quad \text{ABLIKIM} \quad 17AJ \quad \text{BES3} \quad \psi(2S) \to \pi^+\pi^-\pi^0 \end{array} $$

¹ ABLIKIM 17AJ reports $B(\psi(2S) \to \gamma\eta(1405) \to f_0(980)\pi^0 \to \pi^+\pi^-\pi^0) < 5.0 \times 10^{-7}$.

$$ \Gamma(\rho\rho)/\Gamma_{\text{total}} \qquad \Gamma_8/\Gamma $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ <0.58 \quad 99.85 \quad 1,2 \quad \text{AMSLER} \quad 04B \quad \text{CBAR} \quad 0 \bar{p} p \end{array} $$

¹ Assuming that the $\eta(1405)$ decays are saturated by the $\pi\pi\eta$, $K\bar{K}\pi$ and $\rho\rho$ modes.

² Using the data of BAILLON 67 on $\bar{p}p \to K\bar{K}\pi$.

$$ \Gamma(K^*(892)K)/\Gamma(a_0(980)\pi) \qquad \Gamma_{12}/\Gamma_3 $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ 0.084\pm0.024 \quad 1 \quad \text{ADAMS} \quad 01B \quad B852 \quad 18 \text{ GeV } \pi^- p \to K^+ K^- \pi^0 \eta \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

¹ Statistical error only.

$$ \Gamma(\phi\gamma)/\Gamma(\rho^0\gamma) \qquad \Gamma_{11}/\Gamma_{10} $$

$$ \begin{array}{l} \text{VALUE} \quad \text{CL\%} \quad \text{DOCUMENT ID} \quad \text{TECN} \quad \text{COMMENT} \\ \text{0.09}\pm0.03 \quad 1 \quad \text{ABLIKIM} \quad 18I \quad \text{BES3} \quad J/\psi \to \gamma\gamma\phi(1020) \\ 0.13\pm0.04 \quad 2 \quad \text{ABLIKIM} \quad 18I \quad \text{BES3} \quad J/\psi \to \gamma\gamma\phi(1020) \\ <0.77 \quad 95 \quad 3 \quad \text{BAI} \quad 04J \quad \text{BES2} \quad J/\psi \to \gamma\gamma K^+ K^- \end{array} $$

• • • We do not use the following data for averages, fits, limits, etc. • • •

¹ Constructive interference between $X(1835)$ and $\eta(1405)/\eta(1475)$ decays to $\gamma\phi$ is assumed. Also see $\eta(1475)$. ABLIKIM 18I reports the inverse as $11.0 \pm 3.5$.

² Destructive interference between $X(1835)$ and $\eta(1405)/\eta(1475)$ decays to $\gamma\phi$ is assumed. Also see $\eta(1475)$. ABLIKIM 18I reports the inverse as $7.53 \pm 2.49$.

³ Calculated by us from $B(J/\psi \to \eta(1405)\gamma \to \phi\gamma\gamma) < 0.82 \times 10^{-4}$ and $B(J/\psi \to \eta(1405)\gamma \to \rho^0\gamma) = (1.07 \pm 0.17 \pm 0.11) \times 10^{-4}$.

## $\eta(1405)$ REFERENCES

ABLIKIM 23M JHEP 2303 121 18BA PR D100 920030 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 18I PR D97 051101 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 18O PR D97 072014 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 17AJ PR D96 112008 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 13M PR D87 092006 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 12E PR L18 120021 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 11J PR L17 182001 M. Ablikim et al. (BESIII Collab.)
ABLIKIM 08E PR D77 032005 M. Ablikim et al. (BES Collab.)
AHOHE 05B PR D77 02001 R. Ahohe et al. (LCO Collab.)
AMSLER 04B EPJ C33 23 C. Amsler et al. (Crystal Barrel Collab.)
BAI 04J PL B594 47 J.Z. Bai et al. (BES Collab.)
NICHITIU 02 PL B545 261 F. Nichitiu et al. (OBELIX Collab.)
AGCIARRI 01G PL B501 1 M. Acclarri et al. (L3 Collab.)
ADAMS 01B PL B516 264 G.S. Adams et al. (BNL E852 Collab.)
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Also 80 PL L5 219 D.L. Scharre et al. (SLAC, LBL)
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BAIlLOn 67 NC 50A 393 M. Foster et al. (CERN, CDEF, IRAD)