Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

I (J P ) = 21 ( 21 + ) Status:

n

∗∗∗∗

We have omitted some results that have been superseded by later
experiments. See our earlier editions.
Anyone interested in the neutron should look at these two review
articles: D. Dubbers and M.G. Schmidt, “The neutron and its rolein cosmology and particle physics,” Reviews of Modern Physics 83
1111 (2011); and F.E. Wietfeldt and G.L. Greene, “The neutron
lifetime,” Reviews of Modern Physics 83 1173 (2011).

n MASS (atomic mass units u)
The mass is known much more precisely in u (atomic mass units) than in
MeV. See the next data block.
VALUE (u)DOCUMENT ID

TECNCOMMENT

1.00866491595± 0.00000000049
TIESINGA 21 RVUE 2018 CODATA value• • • We do not use the following data for averages, fits, limits, etc. • • •1.00866491588± 0.00000000049
1.00866491600± 0.00000000043
1.00866491597± 0.00000000043
1.00866491560± 0.00000000055
1.00866491578± 0.00000000055
1.008665904 ± 0.000000014

MOHR
MOHR
MOHR
MOHR
MOHR
COHEN

16
12
08
05
99
87

RVUE
RVUE
RVUE
RVUE
RVUE
RVUE

2014 CODATA value
2010 CODATA value
2006 CODATA value
2002 CODATA value
1998 CODATA value
1986 CODATA valuen MASS (MeV)
The mass is known more precisely in u (atomic mass units) than in MeV.
The conversion is: 1 u = 931.494 102 42(28) MeV/c2 (2018 CODATA
value, TIESINGA 21).
VALUE (MeV)

DOCUMENT ID

TECNCOMMENT

939.56542052± 0.00000054
TIESINGA
21 RVUE 2018 CODATA value• • • We do not use the following data for averages, fits, limits, etc. • • •939.5654133 ± 0.0000058
MOHR
16 RVUE 2014 CODATA value
939.565379 ± 0.000021
MOHR
12 RVUE 2010 CODATA value
939.565346 ± 0.000023
MOHR
08 RVUE 2006 CODATA value
939.565360 ± 0.000081
MOHR
05 RVUE 2002 CODATA value
1 KESSLER
939.565331 ± 0.000037
99 SPEC n p → d γ
939.565330 ± 0.000038
MOHR
99 RVUE 1998 CODATA value
2,3 DIFILIPPO
939.56565± 0.00028
94 TRAP Penning trap
939.56563± 0.00028
COHEN
87 RVUE 1986 CODATA value
3,4 GREENE
939.56564± 0.00028
86 SPEC n p → d γ
3 COHEN939.5731± 0.0027
73 RVUE 1973 CODATA value
1 We use the 1998 CODATA u-to-MeV conversion factor (see the heading above) to
get this mass in MeV from the much more precisely measured KESSLER 99 value of
1.00866491637 ± 0.00000000082 u.
2 The mass is known much more precisely in u: m = 1.0086649235 ± 0.0000000023 u.
We use the 1986 CODATA conversion factor to get the mass in MeV.

https://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

3 These determinations are not independent of the mn − m p measurements below.
4 The mass is known much more precisely in u: m = 1.008664919 ± 0.000000014 u.

n MASSVALUE (MeV)EVTS

DOCUMENT ID

TECNCOMMENT

1 CRESTI

939.485± 0.051
59
86 HBC
pp → nn
1 This is a corrected result (see the erratum). The error is statistical. The maximum
systematic error is 0.029 MeV.

(m n − m n )/ m n
A test of CPT invariance. Calculated from the n and n masses, above.
VALUE

DOCUMENT ID(9± 5) × 10−5 OUR EVALUATION

mn − mp
VALUE (MeV)

DOCUMENT ID

TECNCOMMENT

1 TIESINGA

1.29333236± 0.00000046
21 RVUE 2018 CODATA value• • • We do not use the following data for averages, fits, limits, etc. • • •2 MOHR
1.29333205± 0.00000051
16 RVUE 2014 CODATA value
3
1.29333217± 0.00000042
MOHR
12 RVUE 2010 CODATA value
4 MOHR
1.29333214± 0.00000043
08 RVUE 2006 CODATA value
5 MOHR
1.2933317 ± 0.0000005
05 RVUE 2002 CODATA value
6 MOHR
1.2933318 ± 0.0000005
99 RVUE 1998 CODATA value
7 COHEN
1.293318 ± 0.000009
87 RVUE 1986 CODATA value
1.2933328 ± 0.0000072
GREENE
1.293429 ± 0.000036
COHEN
1 The 2018 CODATA mass difference in u is m

86
73

SPEC n p → d γ
RVUE 1973 CODATA value= 1.388 449 33(49) × 10−3 u.

n − mp−3n − m p = 1.388 449 00(51) × 10 u.
3 The 2010 CODATA mass difference in u is m − m = 1.388 449 19(45) × 10−3 u.
np
4 Calculated by us from the MOHR 08 ratio m /m = 1.00137841918(46). In u, m −npnm p = 1.38844920(46) × 10−3 u.
5 Calculated by us from the MOHR 05 ratio m /m = 1.00137841870 ± 0.00000000058.
np
In u, m n − m p = (1.3884487 ± 0.0000006) × 10−3 u.
6 Calculated by us from the MOHR 99 ratio m /m = 1.00137841887 ± 0.00000000058.
np
In u, m n − m p = (1.3884489 ± 0.0000006) × 10−3 u.
7 Calculated by us from the COHEN 87 ratio m /m = 1.001378404 ± 0.000000009. Inn pu, m n − m p = 0.001388434 ± 0.000000009 u.

2 The 2014 CODATA mass difference in u is m

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

n MEAN LIFE
Limits on lifetimes for bound neutrons are given in the section“p PARTIAL
MEAN LIVES.”
We average eight of the best nine measurements, those made with ultracold neutrons (UCN’s). If we include the one in-beam measurement witha comparable error (YUE 13), we get 878.6 ± 0.6 s, where the scale factor
is now 2.2.
For a recent discussion of the long-standing disagreement between inbeam and UCN results, see CZARNECKI 18 (Physical Review Letters 120
202002 (2018)). For a full review of all matters concerning the neutron lifetime until about 2010, see WIETFELDT 11, F.E. Wietfeldt and
G.L. Greene, “The neutron lifetime,” Reviews of Modern Physics 83 1173
(2011).
VALUE (s)DOCUMENT ID

TECNCOMMENT

878.4 ± 0.5 OUR AVERAGE Error includes scale factor of 1.8. See the ideogram
below.
0.22
877.75± 0.28 +GONZALEZ
21 CNTR UCN asym. magnetic trap
− 0.16878.3 ± 1.6 ± 1.0
EZHOV
18 CNTR UCN magneto-gravit. trap+
0.4
1 PATTIE
877.7 ± 0.7 − 0.2
18 CNTR UCN asym. magnetic trap
881.5 ± 0.7 ± 0.6
SEREBROV
18 CNTR UCN gravitational trap
2 ARZUMANOV 15 CNTR UCN double bottle
880.2 ± 1.2
3 STEYERL
882.5 ± 1.4 ± 1.5
12 CNTR UCN material bottle
880.7 ± 1.3 ± 1.2
PICHLMAIER 10 CNTR UCN material bottle
878.5 ± 0.7 ± 0.3
SEREBROV
05 CNTR UCN gravitational trap• • • We do not use the following data for averages, fits, limits, etc. • • •+ 7− 3
887.7 ± 1.2 ± 1.9
881.6 ± 0.8 ± 1.9
886.3 ± 1.2 ± 3.2
886.8 ± 1.2 ± 3.2
885.4 ± 0.9 ± 0.4
889.2 ± 3.0 ± 3.8
882.6 ± 2.7
888.4 ± 3.1 ± 1.1
888.4 ± 2.9
893.6 ± 3.8 ± 3.7
878 ± 27 ± 14887.6 ± 3.0
877 ± 10876 ± 10 ± 19
891 ± 9903 ± 13937 ± 18875 ± 95881 ± 8918 ± 14

887

± 14

https://pdg.lbl.gov

4 WILSON

21

5 YUE
13
6 ARZUMANOV 12
NICO
05
DEWEY
03
ARZUMANOV 00
BYRNE
96
7 MAMPE
93
8 NESVIZHEV... 92
ALFIMENKOV 90
BYRNE90
KOSSAKOW... 89
MAMPE
89
PAUL
89
LAST
88
SPIVAK88
KOSVINTSEV 86
9 BYRNE80
KOSVINTSEV 80
BONDAREN... 78
CHRISTENSEN72

Page 3

CNTR space-based n rate
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
TPC
CNTR
CNTR
SPEC
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR

In-beam n, trapped p
See ARZUMANOV 15
See YUE 13
See NICO 05
See ARZUMANOV 12
Penning trap
UCN material bottle
UCN material bottle
See NESVIZHEVSKII 92
See BYRNE 96
Pulsed beam
See STEYERL 12
Magnetic storage ring
Pulsed beam
Beam
UCN material bottle

See SPIVAK 88

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

1 PATTIE 18 uses a new technique, with a semi-toroidal magneto-gravitational asymmetrictrap and a novel in situ n-detector.
2 ARZUMANOV 15 is a reanalysis of their 2008–2010 dataset, with improved systematic
corrections of of ARZUMANOV 00 and ARZUMANOV 12.
3 STEYERL 12 is a detailed reanalysis of neutron storage loss corrections to the raw dataof MAMPE 89, and it replaces that value.
4 WILSON 21 extract the value from the flux of n escaping the moon using data from theLunar Prospector Neutron Spectrometer.
5 YUE 13 differs from NICO 05 in that a different and better method was used to measure
the neutron density in the fiducial volume. This shifted the lifetime by +1.4 seconds andreduced the previously largest source of systematic uncertainty by a factor of five.
6 ARZUMANOV 12 reanalyzes its systematic corrections in ARZUMANOV 00 and obtains
this corrected value.
7 IGNATOVICH 95 calls into question some of the corrections and averaging procedures
used by MAMPE 93. The response, BONDARENKO 96, denies the validity of thecriticisms.
8 The NESVIZHEVSKII 92 measurement has been withdrawn by A. Serebrov.
9 The BYRNE 80 measurement has been withdrawn (J. Byrne, private communication,1990).
WEIGHTED AVERAGE
878.4±0.5 (Error scaled by 1.8)

χ
GONZALEZEZHOVPATTIESEREBROVARZUMANOVSTEYERLPICHLMAIER
SEREBROV

3.7
0.0
0.9
11.0
2.2
3.9
1.6
0.0
23.3
(Confidence Level = 0.0015)

874

876

878

880

882

884

886

21
18
18
18
15
12
10
05

2

CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR
CNTR

888

neutron mean life (s)n MAGNETIC MOMENT
See the “Quark Model” review.
VALUE (µN )DOCUMENT ID− 1.91304273± 0.00000045

TIESINGA

https://pdg.lbl.gov

Page 4TECN

21COMMENTRVUE 2018 CODATA value

Created: 7/25/2024 17:21

Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)• • • We do not use the following data for averages, fits, limits, etc. • • •− 1.91304273± 0.00000045
MOHR
16 RVUE 2014 CODATA value− 1.91304272± 0.00000045
MOHR
12 RVUE 2010 CODATA value− 1.91304273± 0.00000045
MOHR
08 RVUE 2006 CODATA value− 1.91304273± 0.00000045
MOHR
05 RVUE 2002 CODATA value− 1.91304272± 0.00000045
MOHR
99 RVUE 1998 CODATA value− 1.91304275± 0.00000045
COHEN
87 RVUE 1986 CODATA value
1 GREENE− 1.91304277± 0.00000048
82 MRS
1 GREENE 82 measures the moment to be (1.04187564 ± 0.00000026) × 10−3 Bohrmagnetons. The value above is obtained by multiplying this by m p /m e = 1836.152701 ±0.000037 (the 1986 CODATA value from COHEN 87).

n ELECTRIC DIPOLE MOMENT
A nonzero value is forbidden by both T invariance and P invariance. A
number of early results have been omitted. See RAMSEY 90, GOLUB 94,
and LAMOREAUX 09 for reviews.
The results are upper limits on dn .
VALUE (10−25 e cm)

CL%

DOCUMENT ID

TECNCOMMENT

1 ABEL< 0.1890
20 MRS UCN• • • We do not use the following data for averages, fits, limits, etc. • • •2 SAHOO
199 Hg atom EDM + theory< 0.2295
17< 0.1695
GRANER
16 MRS 199 Hg atom EDM + theory
3 PENDLEBURY 15 MRS Supersedes BAKER 06< 0.3090< 0.5590
SEREBROV
15 MRS UCN’s, hν = 2µn B ± 2dn E
4 SEREBROV< 0.5590
14 MRS See SEREBROV 15
5 BAKER< 0.2990
06 MRS See PENDLEBURY 15
6 HARRIS< 0.6390
99 MRS d = (− 0.1 ± 0.36) × 10−25< 0.9790
ALTAREV
96 MRS See SEREBROV 14< 1.1
95
ALTAREV
92 MRS See ALTAREV 96
< 1.2
95
SMITH
90 MRS See HARRIS 99< 2.6
95
ALTAREV
86 MRS d = (− 1.4 ± 0.6) × 10−25
0.3 ± 4.8
PENDLEBURY 84 MRS Ultracold neutrons< 6
90
ALTAREV
81 MRS d = (2.1 ± 2.4) × 10−25<1690
ALTAREV
79 MRS d = (4.0 ± 7.5) × 10−25
1 ABEL 20 reports d = (0.0 ± 1.1 ± 0.2) × 10−26 e cm value corresponding to the listed
limit.
2 SAHOO 17 develops theory to calculate this limit from the measured limit by GRANER 16
of the 199 Hg atom EDM.
3 PENDLEBURY 15 reports d = (− 0.21 ± 1.82) × 10−26 e cm value corresponding to
the listed limit.
4 SEREBROV 14 includes the data of ALTAREV 96.
5 LAMOREAUX 07 faults BAKER 06 for not including in the estimate of systematic error
an effect due to the Earth’s rotation. BAKER 07 replies (1) that the effect was included
implicitly in the analysis and (2) that further analysis confirms that the BAKER 06 limit
is correct as is. See also SILENKO 07.
6 This HARRIS 99 result includes the result of SMITH 90. However, the averaging of theresults of these two experiments has been criticized by LAMOREAUX 00.

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n MEAN-SQUARE CHARGE RADIUS
The mean-square charge radius of the neutron, r2 , is related to thenneutron-electron scattering length bn e by r2 = 3(m e a0 /m n )bn e ,nwhere m e and m n are the masses of the electron and neutron, and a0 is
the Bohr radius. Numerically, r2 = 86.34 bn e , if we use a0 for a nucleusnwith infinite mass.
VALUE (fm2 )DOCUMENT ID

COMMENT− 0.1155± 0.0017 OUR AVERAGE− 0.115 ± 0.002 ± 0.003
KOPECKY
97 n e scattering (Pb)
− 0.124 ± 0.003 ± 0.005
KOPECKY
97 n e scattering (Bi)− 0.114 ± 0.003
KOESTER
95 n e scattering (Pb, Bi)
1 KROHN− 0.115 ± 0.003
73 n e scattering (Ne, Ar, Kr, Xe)• • • We do not use the following data for averages, fits, limits, etc. • • •2 HEACOCK− 0.1101± 0.0089
21 n interferometry+ 0.007− 0.106 −0.005

3 FILIN+ 0.007− 0.117 −0.011

BELUSHKIN

20

chiral EFT analysis

07

Dispersion analysis− 0.113 ± 0.003 ± 0.004
KOPECKY
95 n e scattering (Pb)
− 0.134 ± 0.009
ALEKSANDR...86 n e scattering (Bi)− 0.114 ± 0.003
KOESTER86 n e scattering (Pb, Bi)− 0.118 ± 0.002
KOESTER
76 n e scattering (Pb)
− 0.120 ± 0.002
KOESTER
76 n e scattering (Bi)− 0.116 ± 0.003
KROHN
66 n e scattering (Ne, Ar, Kr, Xe)
1 KROHN 73 measured − 0.112 ± 0.003 fm2 . This value is as corrected by KOESTER 76.
2 HEACOCK 21 extract the value from Pendelloesung interferometry to measure the neutron structure factors of silicon. This value is strongly anti-correlated with the meansquare thermal atomic displacement.
3 FILIN 20 extract the value based on their chiral-EFT calculation of the deuteron structureradius and use as input the atomic data for the difference of the deuteron and proton
charge radii.

n MAGNETIC RADIUS
This is the rms magnetic radius,

q

r2 .
M

VALUE (fm)DOCUMENT ID+ 0.009 OUR AVERAGE
0.864 −
0.008
0.89 ± 0.03
+ 0.009
0.862 −
0.008

COMMENTEPSTEIN

14

Using e p, e n, π π data

BELUSHKIN

07

Dispersion analysis

n ELECTRIC POLARIZABILITY αnFollowing is the electric polarizability αn defined in terms of the induced
electric dipole moment by D = 4πǫ0 αn E . For a review, see SCHMIEDMAYER 89.
For a very complete reviews of the polarizability of the nucleon and Compton scattering, see SCHUMACHER 05, updated in SCHUMACHER 19,
and GRIESSHAMMER 12.

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VALUE (10−4 fm3 )DOCUMENT ID

TECNCOMMENT11.8 ± 1.1 OUR AVERAGE
11.55± 1.25 ± 0.8
MYERS
14 CNTR γ d → γ d+1.6
112.5 ± 1.8 − 1.3
KOSSERT
03 CNTR γ d → γ p n12.0 ± 1.5 ± 2.0
SCHMIEDM... 91 CNTR n Pb transmission+
3.3
10.7 − 10.7
ROSE
90B CNTR γ d → γ n p• • • We do not use the following data for averages, fits, limits, etc. • • •2 LUNDIN
8.8 ± 2.4 ± 3.0
03 CNTR γ d → γ d
3
13.6
KOLB
00 CNTR γ d → γ n p
4 KOESTER
0.0 ± 5.0
95 CNTR n Pb, n Bi transmission
4.3
11.7 +− 11.7

ROSE

90CNTR See ROSE 90B

8 ± 10
KOESTER
88 CNTR n Pb, n Bi transmission
12 ± 10SCHMIEDM... 88 CNTR n Pb, n C transmission
1 KOSSERT 03 gets α − β =(9.8 ± 3.6 + 2.1 ± 2.2) × 10−4 fm3 , and uses α + β
n
n
n
n
− 1.1
= (15.2 ± 0.5) × 10−4 fm3 from LEVCHUK 00. Thus the errors on αn and βn are
anti-correlated.
2 LUNDIN 03 measures α − β = (6.4 ± 2.4) × 10−4 fm3 and uses accurate valuesNN
for αp and αp and a precise sum-rule result for αn + βn . The second error is a model
uncertainty, and errors on αn and βn are anticorrelated. The data from this paper aer
included in the analysis of MYERS 14.
3 KOLB 00 obtains this value with a lower limit of 7.6 × 10−4 fm3 but no upper limit fromthis experiment alone. Combined with results of ROSE 90, the 1-σ range is (7.6–14.0) ×
10−4 fm3 .
4 KOESTER 95 uses natural Pb and the isotopes 208, 207, and 206. See this paper for a
discussion of methods used by various groups to extract αn from data.

n MAGNETIC POLARIZABILITY βn
VALUE (10−4 fm3 )DOCUMENT ID

TECNCOMMENT

3.7 ± 1.2 OUR AVERAGE
3.65± 1.25 ± 0.8
MYERS
14 CNTR γ d → γ d+
1.312.7 ± 1.8 − 1.6
KOSSERT
03 CNTR γ d → γ p n26.5 ± 2.4 ± 3.0
LUNDIN
03 CNTR γ d → γ d• • • We do not use the following data for averages, fits, limits, etc. • • •3 KOLB
1.6
00 CNTR γ d → γ n p
1 KOSSERT 03 gets α − β =(9.8 ± 3.6 + 2.1 ± 2.2) × 10−4 fm3 , and uses α + β
n
n
n
n
− 1.1
−4
3
= (15.2 ± 0.5) × 10
fm from LEVCHUK 00. Thus the errors on αn and βn are
anti-correlated.
2 LUNDIN 03 measures α − β = (6.4 ± 2.4) × 10−4 fm3 and uses accurate valuesNN
for αp and αp and a precise sum-rule result for αn + βn . The second error is a model
uncertainty, and errors on αn and βn are anticorrelated.
3 KOLB 00 obtains this value with an upper limit of 7.6×10−4 fm3 but no lower limit fromthis experiment alone. Combined with results of ROSE 90, the 1-σ range is (1.2–7.6) ×
10−4 fm3 .

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n CHARGE
See also “ qp + qe /e” in the proton Listings.
VALUE (10−21 e)

DOCUMENT ID

TECNCOMMENT− 0.2± 0.8 OUR AVERAGE
1 BRESSI− 0.1± 1.1
11Neutrality of SF62− 0.4± 1.1
BAUMANN88
Cold n deflection• • • We do not use the following data for averages, fits, limits, etc. • • •3 GAEHLER− 15 ± 2282 CNTR Cold n deflection
1 As a limit, this BRESSI 11 value is < 1 × 10−21 e.
2 The BAUMANN 88 error ± 1.1 gives the 68% CL limits about the the value − 0.4.
3 The GAEHLER 82 error ± 22 gives the 90% CL limits about the the value − 15.

LIMIT ON n n OSCILLATIONS
Mean Time for n n Transition
A test of ∆B=2 baryon number nonconservation. MOHAPATRA 80 and MOHAPATRA 89 discuss the theoretical motivations for looking for n n oscillations. DOVER 83
and DOVER 85 give phenomenological analyses. The best limits come from looking
for the decay of neutrons bound in nuclei. However, these analyses require modeldependent corrections for nuclear effects. See KABIR 83, DOVER 89, ALBERICO 91,
and GAL 00 for discussions. Direct searches for n → n transitions using reactor neutrons are cleaner but give somewhat poorer limits. We include limits for both free andbound neutrons in the Summary Table. See MOHAPATRA 09 and PHILLIPS 16 forrecent reviews.
VALUE (s)CL%

DOCUMENT ID

TECNCOMMENT

1 ABE>4.7 × 108
90
21 CNTR n bound in oxygen
7>8.6 × 10
90
BALDO-...
94 CNTR Reactor (free) neutrons• • • We do not use the following data for averages, fits, limits, etc. • • •2 AHARMIM>1.37 × 108
90
17 SNOn bound in deuteron8>2.7 × 1090
ABE
15C CNTR n bound in oxygen>1.3 × 108
90
CHUNG
02B SOU2 n bound in iron
>1
× 107
90
BALDO-...
90 CNTR See BALDO-CEOLIN 94>1.2 × 108
90
BERGER
90 FREJ n bound in iron5>4.9 × 10
90
BRESSI
90 CNTR Reactor neutrons>4.7 × 105
90
BRESSI
89 CNTR See BRESSI 90>1.2 × 108
90
TAKITA
86 CNTR n bound in oxygen
>1
× 106
90
FIDECARO
85 CNTR Reactor neutrons>8.8 × 107
90
PARK
85B CNTR>3× 107
BATTISTONI 84 NUSX
> 0.27–1.1 × 108
JONES
84 CNTR>2
× 107
CHERRY
83 CNTR
1 ABE 21 supersedes ABE 15C.
2 The AHARMIM 17 value is an unbounded limit (it does not assume a positive lifetime).
The bounded limit is 1.23 × 108 sec.

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LIMIT ON n n′ OSCILLATIONS
Lee and Yang (LEE 56) proposed the existence of mirror world in an
attempt to restore global parity symmetry. A possible candidate for dark
matter. Limits depend on assumptions about fields B and B ′ . See thepapers for details. See BEREZHIANI 18 for a recent discussion.
VALUE (s)CL%

DOCUMENT ID

TECNCOMMENT>448
90
SEREBROV
09A CNTR Assumes B ′ < 100 nT• • • We do not use the following data for averages, fits, limits, etc. • • •
1 BAN
> 1
95
23 CNTR UCN, scan of B field
2 ALMAZAN
22 CNTR STEREO, hidden neutron
search m n − m ′ ≥ 0.
n
3
> 9
95
ABEL
21 CNTR UCN, scan of B field
4 BEREZHIANI 18 CNTR UCN, scan of B field> 17
95
5 ALTAREV> 12
95
09A CNTR UCN, scan 0 ≤ B ≤ 12.5 µT>414
90
SEREBROV
08 CNTR UCN, B field on & off
>103
95
BAN
07 CNTR UCN, B field on & off
1 BAN 23 determine limits on the oscillation time for the δm(nn’) range of 2–59 peV.
p
The quoted value is τ nn′ / cos(β) > 1 sec. for B in 30–1143 µT, for the case β = 0.
2 ALMAZAN 22 reports an experimental constraint on the probability for neutron conversion into a hidden neutron, p < 3.1 × 10−11 at 95% CL, which may be used to set alimit on the n n′ oscillation time.
3 ABEL 21 determine several limits on the oscillation time as a function of the mirror
magnetic field B ′ , and of the fixed angle, β, between the applied magnetic field and B ′ .
The latter is assumed
p to be bound to Earth. Two values are quoted from two analysis
methods: (i) τ nn′ / cos(β) > 9 sec for B ′ in 5–25.4 µT, and (ii) for any angle β,τ nn′ > 6 sec for B ′ in 0.4–25.7 µT. The authors also quote a limit of 352 sec for thecase B ′ = 0 T.
4 The B field was set to (0.09, 0.12, 0.21) G. Limits on oscillation time are valid for any
mirror field B ′ in (0.08–0.17) G, and for aligned fields B and B ′ . For larger values ofB ′ , the limits are significantly reduced.
5 Losses of neutrons due to oscillations to mirror neutrons would be maximal when themagnetic fields B and B ′ in the two worlds were equal. Hence the scan over B by
ALTAREV 09A: the limit applies for any B ′ over the given range. At B ′ = 0, the limit
is 141 s (95% CL).

n DECAY MODES
Mode

Γ1
Γ2
Γ3

Fraction (Γi /Γ)p e− νep e− νe γhydrogen-atom ν e[a]Confidence level100%( 9.2± 0.7) × 10−3
< 2.7
× 10−395%

Charge conservation (Q) violating modeΓ4p νe ν e

Γ5e + e − invisible

Q<× 10−27

8

68%

Baryon number violating decay

https://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)[a] This limit is for γ energies between 0.4 and 782 keV.
n BRANCHING RATIOSΓ p e − ν e γ /Γtotal
VALUE (units 10−3 )

Γ2 /Γ
CL%

DOCUMENT ID

TECNCOMMENT

1 BALES9.17± 0.24 ± 0.64
16 RDK2 Two different set-ups• • • We do not use the following data for averages, fits, limits, etc. • • •2 COOPER
3.09± 0.11 ± 0.30
10 CNTR See BALES 16
3.13± 0.11 ± 0.33
NICO
06 CNTR See COOPER 10
3 BECK<6.9
90
02 CNTR γ, p, e − coincidence
1 BALES 16 gets a branching fraction of (5.82 ± 0.23 ± 0.62) × 10−3 for a photon energy
range 0.4 to 14.0 keV, and with a different detector array, (3.35 ± 0.05 ± 0.15) × 10−3
for 14.1 to 782 keV. Our result above is the sum; the error on the sum is completely
dominated by the error on the lower range.
2 This COOPER 10 result is for γ energies between 15 and 340 keV.
3 This BECK 02 limit is for γ energies between 35 and 100 keV.

Γ hydrogen-atom ν e /Γtotal

VALUE

Γ3 /Γ

CL%

DOCUMENT ID

TECNCOMMENT

1 CZARNECKI 18<0.27 × 10−2
95Lifetime analysis• • • We do not use the following data for averages, fits, limits, etc. • • •2 GREEN<3× 10−2
95
90 RVUE
1 CZARNECKI 18 limit from an analysis of experimental discrepancies on the neutron
lifetime and axial coupling applies as well to other possible exotic neutron decays.
2 GREEN 90 infers that τ (hydrogen-atomν ) > 3 × 104 s by comparing neutron lifetimeemeasurements made in storage experiments with those made in β-decay experiments.
However, the result depends sensitively on the lifetime measurements, and does not of
course take into account more recent measurements of same.

Γ p νe ν e /Γtotal

Γ4 /Γ

Forbidden by charge conservation.

VALUE

CL%

DOCUMENT ID

TECNCOMMENT

1 NORMAN<8 × 10−27
68
96 RVUE 71 Ga → 71 Ge neutrals• • • We do not use the following data for averages, fits, limits, etc. • • •<9.7 × 10−18
90ROY
83 CNTR 113 Cd → 113m In neut.
−21<7.9 × 10
VAIDYA
83 CNTR 87 Rb → 87m Sr neut.
−24<9 × 1090
BARABANOV 80 CNTR 71 Ga → 71 Ge X
<3 × 10−19
NORMAN
79 CNTR 87 Rb → 87m Sr neut.
1 NORMAN 96 gets this limit by attributing SAGE and GALLEX counting rates to thecharge-nonconserving transition 71 Ga → 71 Ge+neutrals rather than to solar-neutrino
reactions.

Γ e + e − invisible /Γtotal

Γ5 /Γ

Baryon number violating decay

VALUE

CL%

DOCUMENT ID

TECNCOMMENT• • • We do not use the following data for averages, fits, limits, etc. • • •1 KLOPF<0.01
90
19 CNTR re-interpretation of
MUND 132 SUN<1× 10−490
18 SPEC Ultracold n, polarized

https://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

1 KLOPF 19 value is for baryon number violating decay of neutron to electrons plus aninvisible state, χ. The limit is valid for KE(e + e − ) range between 32 keV and 664 keV,
strengthening to few × 10−4 above approximately 100 keV.
2 SUN 18 value is for baryon number violating decay of neutron to electrons plus an invisible
state, χ. The limit is valid for 644 keV > KE(e + e − ) > 100 keV. Assuming this decay
χ e e is the only allowed χ decay channel, a 0.01 BR is ruled out for 644 keV > E(e + e − )> 100 keV at over 5σ.

See the related review(s):Baryon Decay Parametersn → p e − ν e DECAY PARAMETERS
See the above “Note on Baryon Decay Parameters.” For discussions ofrecent results, see the references cited at the beginning of the section on
the neutron mean life. For discussions of the values of the weak coupling constants g A and g V obtained using the neutron lifetime and asymmetry parameter A, comparisons with other methods of obtaining these
constants, and implications for particle physics and for astrophysics, see
DUBBERS 91 and WOOLCOCK 91. For tests of the V −A theory ofneutron decay, see EROZOLIMSKII 91B, MOSTOVOI 96, NICO 05, SEVERIJNS 06, and ABELE 08.

λ ≡ gA / gV
VALUE

DOCUMENT ID

TECNCOMMENT− 1.2754 ± 0.0013 OUR AVERAGE Error includes scale factor of 2.7. See the ideogram
below.
1 HASSAN− 1.2796 ± 0.0062
21 SPEC Proton recoil spectrum
2 BECK− 1.2677 ± 0.0028
20 SPEC Proton recoil spectrum
3 MAERKISCH 19 SPEC pulsed cold n, polarized− 1.27641± 0.00045 ± 0.00033
4 BROWN− 1.2772 ± 0.0020
18 UCNA Ultracold n, polarized+
0.00105 MUND− 1.2748 ± 0.0008 − 0.0011
13 SPEC Cold n, polarized− 1.275 ± 0.006 ± 0.015
SCHUMANN 08 CNTR Cold n, polarized
6 MOSTOVOI− 1.2686 ± 0.0046 ± 0.0007
01 CNTR A and B × polarizations− 1.266 ± 0.004
LIAUD
97 TPC
Cold n, polarized, A
7 YEROZLIM... 97 CNTR Cold n, polarized, A− 1.2594 ± 0.0038− 1.262 ± 0.005
BOPP
86 SPEC Cold n, polarized, A• • • We do not use the following data for averages, fits, limits, etc. • • •8 SAUL− 1.27607± 0.00068
20 SPEC Cold n, polarized, A
9− 1.284 ± 0.014
DARIUS
17 SPEC Cold n, unpolarized
10 MENDENHALL13 UCNA See BROWN 18− 1.2755 ± 0.0030+ 0.00331− 1.27590± 0.00239 −0.00377

11 PLASTER

12

UCNA See MENDENHALL 13+ 0.00409− 1.27590 −0.00445

LIU
12 ABELE

10UCNA See PLASTER 12− 1.2739 ± 0.0019− 1.274 ± 0.003− 1.266 ± 0.004− 1.2544 ± 0.0036

https://pdg.lbl.gov

02
ABELE
97D
SCHRECK... 95
EROZOLIM... 91

SPEC
SPEC
TPC
CNTR

See MUND 13
Cold n, polarized, A
See LIAUD 97
See YEROZOLIMSKY 97

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)− 1.226− 1.261− 1.259− 1.263− 1.250− 1.258− 1.263− 1.250± 0.042± 0.012± 0.017± 0.015± 0.036± 0.015± 0.016± 0.009

MOSTOVOYEROZOLIM...
13 STRATOWAEROZOLIM...
13 DOBROZE...
14 KROHN
15 KROPF
15 KROPF

83
79
78
77
75
75
74
74

RVUE
CNTR
CNTR
CNTR
CNTR
CNTR
RVUE
RVUE

Cold n, polarized, A
p recoil spectrum, a
See EROZOLIMSKII 79
See STRATOWA 78
Cold n, polarized, An decay alone
n decay + nuclear ft

WEIGHTED AVERAGE-1.2754±0.0013 (Error scaled by 2.7)

χ
HASSANBECK
MAERKISCH
BROWN
MUND
SCHUMANN
MOSTOVOILIAUDYEROZLIM...
BOPP

2

SPEC
SPEC
7.5
SPEC
3.4
UCNA
0.8
SPEC
0.2
CNTR
CNTR
TPC
5.5
CNTR 17.7
SPEC
35.1(Confidence Level < 0.0001)

-1.29

-1.28

-1.27

-1.26

-1.25

21
20
19
18
13
08
01
97
97
86

-1.24

λ ≡ gA / gV
1 HASSAN 21 include earlier data of DARIUS 17. The value is extracted from the angularcorrelation coefficient a.
2 BECK 20 calculates this value from the measurement of the β-decay e–ν angularecorrelation coefficient a.
3 MAERKISCH 19 gets A = − 0.11985 ± 0.00017 ± 0.00012.
4 BROWN 18 gets A = − 0.12054 ± 0.00044 ± 0.00068 and λ = − 1.2783 ± 0.0022.
We quote the combined values that include the earlier UCNA measurements (MENDENHALL 13).
5 This MUND 13 value includes earlier PERKEO II measurements (ABELE 02 and
ABELE 97D).
6 MOSTOVOI 01 measures the two P-odd correlations A and B, or rather SA and SB,
where S is the n polarization, in free neutron decay.
7 YEROZOLIMSKY 97 makes a correction to the EROZOLIMSKII 91 value.
8 SAUL 20 quote this value of λ under the SM assumption of the Fierz term b = 0. In a
combined fit authors extract a value of λ = − 1.2792 ± 0.0060.
9 DARIUS 17 calculates this value from the measurement of the a parameter (see below).
Data is included in HASSAN 21.
10 MENDENHALL 13 gets A = − 0.11954 ± 0.00055 ± 0.00098 and λ = − 1.2756 ±0.0030. We quote the nearly identical values that include the earlier UCNA measurement(PLASTER 12), with a correction to that result.

https://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

11 This PLASTER 12 value is identical with that given in LIU 10, but the experiment is
now described in detail.
12 This is the combined result of ABELE 02 and ABELE 97D.
13 These experiments measure the absolute value of g /g only.
A V
14 KROHN 75 includes events of CHRISTENSEN 70.
15 KROPF 74 reviews all data through 1972.

e − ASYMMETRY PARAMETER A
This is the neutron-spin electron-momentum correlation coefficient. Unless otherwise
noted, the values are corrected for radiative effects and weak magnetism. In theStandard Model, A is related to λ ≡ gA /gV by A = − 2 λ (λ + 1) / (1 + 3λ2 ); thisassumes that gA and gV are real.
VALUE

DOCUMENT ID

TECNCOMMENT− 0.11958± 0.00021 OUR AVERAGE Error includes scale factor of 1.2. See the ideogram
below.
1 MAERKISCH 19 SPEC pulsed cold n, polarized− 0.11985± 0.00017 ± 0.00012
2− 0.12015± 0.00034 ± 0.00063
BROWN
18 UCNA Ultracold n, polarized+
0.000363− 0.11926± 0.00031 − 0.00042
MUND
13 SPEC Cold n, polarized− 0.1160 ± 0.0009 ± 0.0012
LIAUD
97 TPC
Cold n, polarized
4 YEROZLIM... 97 CNTR Cold n, polarized− 0.1135 ± 0.0014− 0.1146 ± 0.0019
BOPP
86 SPEC Cold n, polarized• • • We do not use the following data for averages, fits, limits, etc. • • •5 SAUL− 0.11972± 0.00025
20 SPEC Cold n, polarized
6 MENDENHALL13 UCNA See BROWN 18− 0.11952± 0.00110+ 0.00123− 0.11966± 0.00089 −0.00140+ 0.00123− 0.11966± 0.00089 −0.00140− 0.1138 ± 0.0046 ± 0.0021− 0.1189 ± 0.0007− 0.1168 ± 0.0017− 0.1189 ± 0.0012− 0.1160 ± 0.0009 ± 0.0011− 0.1116 ± 0.0014

7 PLASTERLIU
PATTIE
8 ABELE
9 MOSTOVOI12UCNA See MENDENHALL 13

10

UCNA See PLASTER 12

09
02
01
ABELE
97D
SCHRECK... 95
EROZOLIM... 91

SPEC
SPEC
CNTR
SPEC
TPC
CNTR

Ultracold n, polarized
See MUND 13
Inferred
Cold n, polarized
See LIAUD 97
See YEROZOLIMSKY 97
CNTR Cold n, polarized
CNTR Cold n, polarized

10 EROZOLIM... 79− 0.114 ± 0.005
10 KROHN− 0.113 ± 0.006
75
1 MAERKISCH 19 further derive a value for the CKM-element V
ud = 0.97351 ± 0.00060,
using τ n = 879.7(8) sec and the relation from CZARNECKI 18.
2 BROWN 18 gets A = − 0.12054 ± 0.00044 ± 0.00068 and λ = − 1.2783 ± 0.0022.
We quote the combined values that include the earlier UCNA measurements (MENDENHALL 13).
3 This MUND 13 value includes earlier PERKEO II measurements (ABELE 02 and
ABELE 97D), with a correction to those results.
4 YEROZOLIMSKY 97 makes a correction to the EROZOLIMSKII 91 value.
5 Under the SM assumption that the Fierz term b = 0, SAUL 20 obtain the quoted
asymmetry parameter A and λ = − 1.27607 ± 0.00068. In a combined fit authors extract
the values A = − 0.1209 ± 0.0015, λ = − 1.2792 ± 0.0060, and b = 0.017 ± 0.021.
6 MENDENHALL 13 gets A = − 0.11954 ± 0.00055 ± 0.00098 and λ = − 1.2756 ±0.0030. We quote the nearly identical values that include the earlier UCNA measurement(PLASTER 12), with a correction to that result.
7 This PLASTER 12 value is identical with that given in LIU 10, but the experiment is
now described in detail.
8 This is the combined result of ABELE 02 and ABELE 97D.

https://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

9 MOSTOVOI 01 calculates this from its measurement of λ=g /g above.
A V
10 These results are not corrected for radiative effects and weak magnetism, but the corrections are small compared to the errors.
WEIGHTED AVERAGE-0.11958±0.00021 (Error scaled by 1.2)

χ
MAERKISCH
BROWN
MUND
LIAUD
YEROZLIM...
BOPP

19
18
13
97
97
86

SPEC
UCNA
SPEC
TPC
CNTR
SPEC

2

1.7
0.6
0.4

2.7
(Confidence Level = 0.261)-0.122-0.121-0.12-0.119-0.118-0.117-0.116e − asymmetry parameter A

ν e ASYMMETRY PARAMETER B
This is the neutron-spin antineutrino-momentum correlation coefficient. In the Standard Model, B is related to λ ≡ gA /gV by B = 2λ(λ − 1) / (1 + 3λ2 ); this assumes
that gA and gV are real.
VALUE

DOCUMENT ID

TECNCOMMENT

0.9807± 0.0030 OUR AVERAGE
0.9802± 0.0034 ± 0.0036
SCHUMANN 07 CNTR Cold n, polarized
0.967 ± 0.006 ± 0.010
KREUZ
05 CNTR Cold n, polarized
0.9801± 0.0046
SEREBROV
98 CNTR Cold n, polarized
0.9894± 0.0083
KUZNETSOV 95 CNTR Cold n, polarized
1.00 ± 0.05
CHRISTENSEN70 CNTR Cold n, polarized
0.995 ± 0.034
EROZOLIM... 70C CNTR Cold n, polarized• • • We do not use the following data for averages, fits, limits, etc. • • •1 MOSTOVOI
0.9876± 0.0004
01 CNTR Inferred
1 MOSTOVOI 01 calculates this from its measurement of λ=g /g above.
A V

PROTON ASYMMETRY PARAMETER C
Describes the correlation between the neutron spin and the proton momentum. In theStandard Model, C is related to λ ≡ gA /gV by C = −xc (A + B) = xc 4λ/(1 +3λ2 ), where xc = 0.27484 is a kinematic factor; this assumes that gA and gV are
real.
VALUE

DOCUMENT ID− 0.2377± 0.0010 ± 0.0024

SCHUMANN

https://pdg.lbl.gov

Page 14TECN

08COMMENTCNTR Cold n, polarized

Created: 7/25/2024 17:21

Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)e-ν e ANGULAR CORRELATION COEFFICIENT a

For a review of past experiments and plans for future measurements of the a parameter,
see WIETFELDT 05. In the Standard Model, a is related to λ ≡ gA /gV by a = (1− λ2 ) / (1 + 3λ2 ); this assumes that gA and gV are real.

VALUE

DOCUMENT ID

TECNCOMMENT− 0.1049 ± 0.0013 OUR AVERAGE Error includes scale factor of 1.8.
1 HASSAN− 0.10782± 0.00124 ± 0.00133
21 SPEC Proton recoil spectrum− 0.10430± 0.00084
BECK
20 SPEC Proton recoil spectrum− 0.1054 ± 0.0055
BYRNE
02 SPEC Proton recoil spectrum− 0.1017 ± 0.0051
STRATOWA 78 CNTR Proton recoil spectrum− 0.091 ± 0.039
GRIGOREV
68 SPEC Proton recoil spectrum• • • We do not use the following data for averages, fits, limits, etc. • • •2 DARIUS− 0.1090 ± 0.0030 ± 0.0028
17 SPEC Cold n, unpolarized
3 MOSTOVOI− 0.1045 ± 0.0014
01 CNTR Inferred
1 The result of HASSAN 21 includes the data of DARIUS 17, and thus supersedes thoseentries. HASSAN 21 uses the asymmetry in time-of-flight between the beta electron andrecoil proton in delayed coincidence.
2 DARIUS 17 exploits a ”wishbone” correlation, where the p time of flight is correlated withthe momentum of the electron in delayed coincidence. Data is included in HASSAN 21.
3 MOSTOVOI 01 calculates this from its measurement of λ=g /g above.
A V

φAV , PHASE OF g A RELATIVE TO g V

Time reversal invariance requires this to be 0 or 180◦ . This is related to D given in
the next data block and λ ≡ gA /gV by sin(φAV ) ≡ D(1+3λ2 )/2 λ ; this assumes
that gA and gV are real.

VALUE (◦ )CL%

DOCUMENT ID

TECNCOMMENT

180.017± 0.026 OUR AVERAGE
180.012± 0.028
68
CHUPP
12 CNTR Cold n, polarized > 91%
180.04 ± 0.09
SOLDNER
04 CNTR Cold n, polarized
180.08 ± 0.13
LISING
00 CNTR Polarized > 93%• • • We do not use the following data for averages, fits, limits, etc. • • •180.013± 0.028
MUMM
179.71 ± 0.39
EROZOLIM...
180.35 ± 0.43
EROZOLIM...
1 KROPF
181.1 ± 1.3
180.14 ± 0.22
STEINBERG
1 KROPF 74 reviews all data through 1972.

11
78
74
74
74

CNTR
CNTR
CNTR
RVUE
CNTR

See CHUPP 12
Cold n, polarized
Cold n, polarizedn decay
Cold n, polarized

TRIPLE CORRELATION COEFFICIENT D
These are measurements of the component of n spin perpendicular to the decay planein β decay. Should be zero if T invariance is not violated.
VALUE (units 10−4 )DOCUMENT ID

TECNCOMMENT− 1.2 ± 2.0 OUR AVERAGE− 0.94± 1.89± 0.97
CHUPP
12 CNTR Cold n, polarized > 91%− 2.8 ± 6.4 ± 3.0
SOLDNER
04 CNTR Cold n, polarized− 6 ± 12 ± 5
LISING
00 CNTR Polarized > 93%• • • We do not use the following data for averages, fits, limits, etc. • • •− 0.96± 1.89± 1.01
+ 22 ± 30− 27 ± 50− 11 ± 17

MUMM
EROZOLIM...
1 EROZOLIM...
STEINBERG

https://pdg.lbl.gov

Page 15

11
78
74
74

CNTR
CNTR
CNTR
CNTR

See CHUPP 12
Cold n, polarized
Cold n, polarized
Cold n, polarized

Created: 7/25/2024 17:21

Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

1 EROZOLIMSKII 78 says asymmetric proton losses and nonuniform beam polarization
may give a systematic error up to 30 × 10−4 , thus increasing the EROZOLIMSKII 74
error to 50 × 10−4 . STEINBERG 74 and STEINBERG 76 estimate these systematic
errors to be insignificant in their experiment.

TRIPLE CORRELATION COEFFICIENT R
Another test of time-reversal invariance. R measures the polarization of the electron in
the direction perpendicular to the plane defined by the neutron spin and the electron
momentum. R = 0 for T invariance.
VALUE

DOCUMENT ID

TECNCOMMENT

1 KOZELA+ 0.004± 0.012 ± 0.005
12 CNTR Mott polarimeter• • • We do not use the following data for averages, fits, limits, etc. • • •+ 0.008± 0.015 ± 0.005
KOZELA
09 CNTR See KOZELA 12
1 KOZELA 12 also measures the polarization of the electron along the direction of theneutron spin. This is nonzero in the Standard Model; the correlation coefficient is N =+ 0.067 ± 0.011 ± 0.004.

FIERZ INTERFERENCE TERM b
The coefficient of the Fierz interference term, b, probes additional contributions to
the differential decay rate of the neutron from scalar or tensor current interactions,beyond the Standard Model.
VALUE

DOCUMENT ID

TECNCOMMENT

1 SAUL
0.017± 0.020 ± 0.003
20 SPEC Cold n, polarized
1 In a combined fit SAUL 20 extract this best fit value of the Fierz interference term b andthe values A = − 0.1209 ± 0.0015 and λ = − 1.2792 ± 0.0060. For b it translates into
a 90% CL region of − 0.018 ≤ b ≤ 0.052 as a function of A.

n REFERENCES
We have omitted some papers that have been superseded by later experiments. See our earlier editions.
BAN
23
ALMAZAN
22
ABE
21
ABEL
21
GONZALEZ21
HASSAN21
HEACOCK21TIESINGA
21
WILSON
21
ABEL
20
BECK
20
FILIN
20
SAUL
20
KLOPF
19
MAERKISCH 19
SCHUMACHER 19
BEREZHIANI 18BROWN
18CZARNECKI
18
EZHOV
18
PATTIE
18
SEREBROV
18
Also
SUN
18
AHARMIM
17
DARIUS
17
SAHOO
17
BALES
16

PRL 131 191801
PRL 128 061801
PR D103 012008
PL B812 135993
PRL 127 162501
PR C103 045502
SCI 373 1239
RMP 93 025010
PR C104 045501
PRL 124 081803
PR C101 055506
PRL 124 082501
PRL 125 112501
PRL 122 222503
PRL 122 242501
LHEP 4 4
EPJ C78 717
PR C97 035505
PRL 120 202002
JETPL 107 671
SCI 360 627
PR C97 055503
JETPL 106 623
PR C97 052501
PR D96 092005
PRL 119 042502
PR D95 013002
PRL 116 242501

https://pdg.lbl.gov

G. Ban et al.
(CAEN, ZURI, ISNG, SORB+)
H. Almazan et al.
(STEREO Collab.)
K. Abe et al.
(Super-Kamiokande Collab.)
C. Abel et al.
(nEDM Collab.)
F.M. Gonzalez et al.
(UCNtau Collab.)
M.T. Hassan et al.
(aCORN Collab)
B. Heacock et al.
(NIST, RIKEN, NAGO+)
E. Tiesinga et al.
(NIST)
J.T. Wilson et al.
(JHU, DURH)
C. Abel et al.
(nEDM Collab.)
M. Beck et al.
(aSPECT Collab.)
A.A. Filin et al.
H. Saul et al.
(PERKEO III Collab.)
M. Klopf et al.
(PERKEO II Collab.)
B. Maerkisch et al.
(TUM, ILL, +)M. Schumacher(GOET)
Z. Berezhiani et al.
(AQUI, INFN, ILLG+)
M.A.-P. Brown et al.
(UCNA Collab.)
A. Czarnecki, W.J. Marciano, A. Sirlin(ALBE+)
V.F. Ezhov et al.
(PNPI, LENSU, CAEN+)
R.W. Pattie Jr. et al.
(LASL, IND, NCSU+)
A.P. Serebrov et al.
(PNPI, ILLG, RAL)
A.P. Serebrov et al.
(PNPI, ILLG, RAL)
X. Sun et al.
(UCNA Collab.)
B. Aharmin et al.
(SNO Collab.)
G. Darius et al.
(aCORN at NIST)
B.K. Sahoo(AHMEB)
M.J. Bales et al.
(RDK II Collab.)

Page 16Created: 7/25/2024 17:21

Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

GRANER
16
Also
MOHR
16
PHILLIPS
16ABE
15C
ARZUMANOV 15
PENDLEBURY 15
SEREBROV
15
EPSTEIN
14
MYERS
14
SEREBROV
14
MENDENHALL 13
MUND
13
YUE
13
ARZUMANOV 12CHUPPGRIESSHAM...
KOZELA
MOHR
PLASTERSTEYERLBRESSIDUBBERS
MUMM
WIETFELDTCOOPER
LIU
Also
PICHLMAIER
ALTAREV
KOZELALAMOREAUX
MOHAPATRAPATTIESEREBROV
ABELE
MOHR
SCHUMANNSEREBROV
BAKER
BAN
BELUSHKINLAMOREAUXSCHUMANN
SILENKO

12
12
12
12
12
12
11
11
11
11
10
10
10
09A
09
09
09
09
09A
08
08
08
08
07
07
07
07
07
07

BAKER
06
NICO
06
SEVERIJNS
06
KREUZ
05
MOHR
05
NICO
05
SCHUMACHER 05
SEREBROV05
Also
WIETFELDTSOLDNER
DEWEY
KOSSERT
Also
LUNDIN
ABELE
BECK

05
04
03
03

BYRNE
CHUNG
MOSTOVOI

02
02B
01

03
02
02

ARZUMANOV 00
GAL00

PRL 116 161601
B. Graner et al.
(WASH)
PRL 119 119901 (errat.) B. Graner et al.
(WASH)
RMP 88 035009
P.J. Mohr, D.B. Newell, B.N. Taylor(NIST)PRPL 612 1
D.G. Phillips II et al.
PR D91 072006
K. Abe et al.
(Super-Kamiokande Collab.)
PL B745 79
S. Arzumanov et al.
(ILLG, KIAE)PR D92 092003
J.M. Pendlebury et al.
(ETHZ, PSI, SUSS)PR C92 055501
A.P. Serebrov et al.
(PNPI, ILLG, IOFF)PR D90 074027
Z. Epstein, G. Paz, J. Roy(UMD, WAYN)
PRL 113 262506
L.S. Myers et al.
(COMPTON/MAX-lab Collab.)
JETPL 99 4
A.P. Serebrov et al.
(PNPI, ILL, IOFF)PR C87 032501
M.P. Mendenhall et al.
(UCNA Collab.)
PRL 110 172502
D. Mund et al.
(HEID, ILLG)
PRL 111 222501
A.T. Yue et al.
(UMD, NIST, TENN, ORNL+)JETPL 95 224
S.S. Arzumanov et al.
(KIAE)
Translated from ZETFP 95 248.
PR C86 035505
T.E. Chupp et al.
(MICH, UCB, WASH+)
PPNP 67 841
H.W. Griesshammer et al.
(GWU, MCHS+)PR C85 045501
A. Kozela et al.
(nTRV Collab.)
RMP 84 1527
P.J. Mohr, B.N. Taylor, D.B. Newell(NIST)PR C86 055501
B. Plaster et al.
(UCNA Collab.)
PR C85 065503
A. Steyerl et al.
(URI, SUSS)PR A83 052101
G. Bressi et al.
(LEGN, PAVII, PADO, TRST+)RMP 83 1111
D. Dubbers, M.G. Schmidt(HEID)
PRL 107 102301
H.P. Mumm et al.
(NIST, WASH, MICH, LBL+)
RMP 83 1173
F.E. Wietfeldt, G.L. Greene(TULA, TENN)PR C81 035503
R.L. Cooper et al.
(MICH, NIST, TULA+)PRL 105 181803
J. Liu et al.
(UCNA Collab.)
PRL 105 219903 (errat.) J. Liu et al.
(UCNA Collab.)
PL B693 221
A. Pichlmaier et al.
(TUM, PNPI, ILLG)PR D80 032003
I. Altarev et al.
(TUM, RAL, CAEN+)
PRL 102 172301
A. Kozela et al.
(JAGL, CRAC, PSI, CAEN+)
JP G36 104002
S.K. Lamoreaux, R. Golub(YALE, NCSU)
JP G36 104006
R.N. Mohapatra(UMD)
PRL 102 012301
R.W. Pattie Jr. et al.
(Los Alamos UCNA Collab.)
NIM A611 137
A.P. Serebrov et al.
(PNPI, IOFF, ILLG+)
PPNP 60 1
H. Abele(HEID)
RMP 80 633
P.J. Mohr, B.N. Taylor, D.B. Newell(NIST)
PRL 100 151801
M. Schumann et al.
(HEID, ILLG, KARL+)PL B663 181
A.P. Serebrov et al.
(PNPI, IOFF, ILLG+)
PRL 98 149102
C.A. Baker et al.
(RAL, SUSS, ILLG)PRL 99 161603
G. Ban et al.
(CAEN, JAGL, PSI, JINR+)
PR C75 035202
M.A. Belushkin, H.W. Hammer, U.-G. Meissner (BONN+)PRL 98 149101
S.K. Lamoreaux, R. Golub(YALE, NCSU)
PRL 99 191803
M. Schumann et al.
(HEID, ILLG, KARL+)PPNL 4 468
A.Ya. Silenko(Belarussian U.)
Translated from PFECAY 6 784.
PRL 97 131801
C.A. Baker et al.
(RAL, SUSS, ILLG)
NAT 444 1059
J.S. Nico et al.
(NIST, TULN, MICH, UMD+)
RMP 78 991
N. Severijns, M. Beck, O. Naviliat-Cuncic(LEUV+)PL B619 263
M. Kreuz et al.
(HEID, ILLG, MAINZ, KARL+)RMP 77 1
P.J. Mohr, B.N. Taylor(NIST)PR C71 055502
J.S. Nico et al.
(NIST, TULN, IND, TENN+)
PPNP 55 567
M. Schumacher(GOET)PL B605 72
A.P. Serebrov et al.
(PNPI, JINR, ILLG)SPU 48 867
A.P. Serebrov et al.
(PPNI, JINR, ILLG)
Translated from UFN 175 905.
MPL A20 1783
F.E. Wietfeldt(TULN)PL B581 49
T. Soldner et al.
(ILLG, TUM)
PRL 91 152302
M.S. Dewey et al.
(NIST, TULN, IND+)
EPJ A16 259
K. Kossert et al.
(Mainz MAMI Collab.)
PRL 88 162301
K. Kossert et al.
(Mainz MAMI Collab.)
PRL 90 192501
M. Lundin et al.
PRL 88 211801
H. Abele et al.
(PERKEO-II Collab.)
JETPL 76 332
M. Beck et al.
(LEUV, SUSS, KIAE, PNPI)Translated from ZETFP 76 392.
JP G28 1325
J. Byrne et al.
PR D66 032004
J. Chung et al.
(SOUDAN-2 Collab.)
PAN 64 1955
Yu.A. Mostovoi et al.
Translated from YAF 64 2040.
PL B483 15
S. Arzumanov et al.
PR C61 028201
A. Galhttps://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

KOLB
LAMOREAUXLEVCHUK
LISINGHARRISKESSLER
MOHR
Also
SEREBROV

00
00
00
00
99
99
99

PRL 85 1388
N.R. Kolb et al.
PR D61 051301
S.K. Lamoreaux, R. Golub
NP A674 449
M.I. Levchuk, A.I. L’vov(BELA, LEBD)PR C62 055501
L.J. Lising et al.
(NIST emiT Collab.)
PRL 82 904
P.G. Harris et al.
PL A255 221
E.G. Kessler Jr et al.
JPCRD 28 1713
P.J. Mohr, B.N. Taylor(NIST)
RMP 72 351
P.J. Mohr, B.N. Taylor(NIST)
98
JETP 86 1074
A.P. Serebrov et al.
Translated from ZETF 113 1963.
ABELE
97D PL B407 212
H. Abele et al.
(HEIDP, ILLG)
KOPECKY97
PR C56 2229
S. Kopecky et al.
LIAUD
97
NP A612 53
P. Liaud et al.
(ILLG, LAPP)YEROZLIM... 97
PL B412 240
B.G. Erozolimsky et al.
(HARV, PNPI, KIAE)ALTAREV96
PAN 59 1152
I.S. Altarev et al.
(PNPI)
Translated from YAF 59 1204.
BONDAREN... 96
JETPL 64 416
L.N. Bondarenko et al.
(KIAE)
Translated from ZETFP 64 382.
BYRNE
96
EPL 33 187
J. Byrne et al.
(SUSS, ILLG)
MOSTOVOI96
PAN 59 968
Y.A. Mostovoy(KIAE)
Translated from YAF 59 1013.
NORMAN96
PR D53 4086
E.B. Norman, J.N. Bahcall, M. Goldhaber(LBL+)
IGNATOVICH 95
JETPL 62 1
V.K. Ignatovich(JINR)
Translated from ZETFP 62 3.
KOESTER95
PR C51 3363
L. Koester et al.
(TUM, JINR, LATV)
KOPECKY95
PRL 74 2427
S. Kopecky et al.
KUZNETSOV 95
PRL 75 794
I.A. Kuznetsov et al.
(PNPI, KIAE, HARV+)
SCHRECK...
95
PL B349 427
K. Schreckenbach et al.
(TUM, ILLG, LAPP)BALDO-...
94
ZPHY C63 409
M. Baldo-Ceolin et al.
(HEID, ILLG, PADO+)DIFILIPPO94
PRL 73 1481
F. DiFilippo et al.
(MIT)
Also
PRL 71 1998
V. Natarajan et al.
(MIT)
GOLUB
94
PRPL 237C 1
R. Golub, K. Lamoreaux(HAHN, WASH)
MAMPE
93
JETPL 57 82
B. Mampe et al.
(KIAE)
Translated from ZETFP 57 77.
ALTAREV92
PL B276 242
I.S. Altarev et al.
(PNPI)NESVIZHEV... 92
JETP 75 405
V.V. Nesvizhevsky et al.
(PNPI, JINR)
Translated from ZETF 102 740.
ALBERICO91
NP A523 488
W.M. Alberico, A. de Pace, M. Pignone(TORI)DUBBERS91
NP A527 239c
D. Dubbers(ILLG)Also
EPL 11 195
D. Dubbers, W. Mampe, J. Dohner(ILLG, HEID)EROZOLIM... 91
PL B263 33
B.G. Erozolimsky et al.
(PNPI, KIAE)
Also
SJNP 52 999
B.G. Erozolimsky et al.
(PNPI, KIAE)
Translated from YAF 52 1583.
EROZOLIM... 91B SJNP 53 260
B.G. Erozolimsky, Y.A. Mostovoy(KIAE)
Translated from YAF 53 418.
SCHMIEDM... 91
PRL 66 1015
J. Schmiedmayer et al.
(TUW, ORNL)WOOLCOCK 91
MPL A6 2579
W.S. Woolcock(CANB)ALFIMENKOV 90
JETPL 52 373
V.P. Alfimenkov et al.
(PNPI, JINR)
Translated from ZETFP 52 984.
BALDO-...
90
PL B236 95
M. Baldo-Ceolin et al.
(PADO, PAVI, HEIDP+)
BERGER90
PL B240 237
C. Berger et al.
(FREJUS Collab.)
BRESSI90
NC 103A 731
G. Bressi et al.
(PAVI, ROMA, MILA)BYRNE
90PRL 65 289
J. Byrne et al.
(SUSS, NBS, SCOT, CBNM)
GREEN
90
JP G16 L75
K. Green, D. Thompson(RAL)
RAMSEY
90
ARNPS 40 1
N.F. Ramsey(HARV)ROSE
90
PL B234 460
K.W. Rose et al.
(GOET, MPCM, MAINZ)
ROSE
90B NP A514 621
K.W. Rose et al.
(GOET, MPCM)
SMITH
90
PL B234 191
K.F. Smith et al.
(SUSS, RAL, HARV+)BRESSI89
ZPHY C43 175
G. Bressi et al.
(INFN, MILA, PAVI, ROMA)DOVER
89
NIM A284 13
C.B. Dover, A. Gal, J.M. Richard(BNL, HEBR+)KOSSAKOW... 89
NP A503 473
R. Kossakowski et al.
(LAPP, SAVO, ISNG+)
MAMPE
89
PRL 63 593
W. Mampe et al.
(ILLG, RISL, SUSS, URI)
MOHAPATRA 89
NIM A284 1
R.N. Mohapatra
(UMD)
PAUL
89
ZPHY C45 25
W. Paul et al.
(BONN, WUPP, MPIK, ILLG)
SCHMIEDM... 89
NIM A284 137
J. Schmiedmayer, H. Rauch, P. Riehs(WIEN)BAUMANN88
PR D37 3107
J. Baumann et al.
(BAYR, MUNI, ILLG)
KOESTER88
ZPHY A329 229
L. Koester, W. Waschkowski, J. Meier(MUNI, TUM)
LAST
88
PRL 60 995
I. Last et al.
(HEIDP, ILLG, ANL)SCHMIEDM... 88
PRL 61 1065
J. Schmiedmayer, H. Rauch, P. Riehs
(TUW)
Also
PRL 61 2509 (errat.)
J. Schmiedmayer, H. Rauch, P. Riehs(TUW)
SPIVAK88
JETP 67 1735
P.E. Spivak(KIAE)
Translated from ZETF 94 1.
COHEN
87
RMP 59 1121
E.R. Cohen, B.N. Taylor(RISC, NBS)

https://pdg.lbl.gov

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Citation: S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024)

ALEKSANDR... 86
ALTAREV

86

BOPP
Also
CRESTI
Also
GREENE
KOESTERKOSVINTSEV

86
86
86
86
86

TAKITA
86
DOVER
85
FIDECARO
85
PARK
85B
BATTISTONI 84
JONES84
PENDLEBURY 84
CHERRY
83
DOVER
83
KABIR
83
MOSTOVOY
83
ROY
VAIDYAGAEHLER
GREENEALTAREVBARABANOV

83
83
82
82
81
80

BYRNE
80
KOSVINTSEV 80
MOHAPATRA 80
ALTAREV79
EROZOLIM...

79

NORMAN79
BONDAREN... 78
Also
EROZOLIM...

78

STRATOWAEROZOLIM...

78
77

KOESTERSTEINBERG
DOBROZE...
KROHNEROZOLIM...

76
76
75
75
74

KROPF
74
Also
STEINBERG
74
COHEN
73
KROHN
73
CHRISTENSEN 72
CHRISTENSEN 70
EROZOLIM... 70C
GRIGOREV
68
KROHN
LEE

66
56

SJNP 44 900
Yu.A. Aleksandrov et al.
Translated from YAF 44 1384.
JETPL 44 460
I.S. Altarev et al.
(PNPI)
Translated from ZETFP 44 360.
PRL 56 919
P. Bopp et al.
(HEIDP, ANL, ILLG)
ZPHY C37 179
E. Klempt et al.
(HEIDP, ANL, ILLG)
PL B177 206
M. Cresti et al.
(PADO)PL B200 587 (errat.)
M. Cresti et al.
(PADO)PRL 56 819
G.L. Greene et al.
(NBS, ILLG)
Physica B137 282
L. Koester et al.
JETPL 44 571
Y.Y. Kosvintsev, V.I. Morozov, G.I. Terekhov(KIAE)
Translated from ZETFP 44 444.
PR D34 902
M. Takita et al.
(KEK, TOKY+)PR C31 1423
C.B. Dover, A. Gal, J.M. Richard(BNL)
PL 156B 122
G. Fidecaro et al.
(CERN, ILLG, PADO+)NP B252 261
H.S. Park et al.
(IMB Collab.)
PL 133B 454
G. Battistoni et al.
(NUSEX Collab.)
PRL 52 720
T.W. Jones et al.
(IMB Collab.)
PL 136B 327
J.M. Pendlebury et al.
(SUSS, HARV, RAL+)PRL 50 1354
M.L. Cherry et al.
(PENN, BNL)PR D27 1090
C.B. Dover, A. Gal, J.M. Richard(BNL)
PRL 51 231
P.K. Kabir(HARV)JETPL 37 196
Y.A. Mostovoy(KIAE)
Translated from ZETFP 37 162.
PR D28 1770
A. Roy et al.
(TATA)
PR D27 486
S.C. Vaidya et al.
(TATA)
PR D25 2887
R. Gahler, J. Kalus, W. Mampe(BAYR, ILLG)
Metrologia 18 93
G.L. Greene et al.
(YALE, HARV, ILLG+)
PL 102B 13
I.S. Altarev et al.
(PNPI)JETPL 32 359
I.R. Barabanov et al.
(PNPI)
Translated from ZETFP 32 384.
PL 92B 274
J. Byrne et al.
(SUSS, RL)
JETPL 31 236
Y.Y. Kosvintsev et al.
(JINR)
Translated from ZETFP 31 257.
PRL 44 1316
R.N. Mohapatra, R.E. Marshak(CUNY, VPI)JETPL 29 730
I.S. Altarev et al.
(PNPI)
Translated from ZETFP 29 794.
SJNP 30 356
B.G. Erozolimsky et al.
(KIAE)
Translated from YAF 30 692.
PRL 43 1226
E.B. Norman, A.G. Seamster(WASH)JETPL 28 303
L.N. Bondarenko et al.
(KIAE)
Translated from ZETFP 28 328.
Smolenice Conf.
P.G. Bondarenko(KIAE)SJNP 28 48
B.G. Erozolimsky et al.
(KIAE)
Translated from YAF 28 98.
PR D18 3970
C. Stratowa, R. Dobrozemsky, P. Weinzierl(SEIB)JETPL 23 663
B.G. Erozolimsky et al.
(KIAE)
Translated from ZETFP 23 720.
PRL 36 1021
L. Koester et al.
PR D13 2469
R.I. Steinberg et al.
(YALE, ISNG)
PR D11 510
R. Dobrozemsky et al.
(SEIB)PL 55B 175
V.E. Krohn, G.R. Ringo(ANL)
JETPL 20 345
B.G. Erozolimsky et al.
Translated from ZETFP 20 745.
ZPHY 267 129
H. Kropf, E. Paul
(LINZ)NP A154 160
H. Paul(VIEN)
PRL 33 41
R.I. Steinberg et al.
(YALE, ISNG)
JPCRD 2 664
E.R. Cohen, B.N. Taylor(RISC, NBS)PR D8 1305
V.E. Krohn, G.R. Ringo
PR D5 1628
C.J. Christensen et al.
(RISO)PR C1 1693
C.J. Christensen, V.E. Krohn, G.R. Ringo(ANL)
PL 33B 351
B.G. Erozolimsky et al.
(KIAE)SJNP 6 239
V.K. Grigoriev et al.
(ITEP)
Translated from YAF 6 329.
PR 148 1303
V.E. Krohn, G.R. Ringo
PR 104 254
T.D. Lee, C.N. Yang
(COLU, BNL)

https://pdg.lbl.gov

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