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

Heavy Charged Lepton Searches
Charged Heavy Lepton MASS LIMITS
Sequential Charged Heavy Lepton (L± ) MASS LIMITS
These experiments assumed that a fourth generation L± decayed to a fourth generationνL (or L0 ) where νL was stable, or that L± decays to a light νℓ via mixing.
See the “Quark and Lepton Compositeness, Searches for” Listings for limits on radiatively decaying excited leptons, i.e. ℓ∗ → ℓ γ. See the “WIMPs and other Particle
Searches” section for heavy charged particle search limits in which the charged particle
could be a lepton.
VALUE (GeV)CL%

DOCUMENT ID

TECN>100.8>101.995
95

ACHARD
ACHARD> 81.595

ACKERSTAFF 98C OPAL
ACKERSTAFF 98C OPAL
1 ACCIARRI
96G L3
ALEXANDER 96P OPALBUSKULIC
96S ALEPCOMMENT

Decay to ν W
m L − m 0 > 15 GeVL• • • We do not use the following data for averages, fits, limits, etc. • • •> 80.2

95

< 48 or > 61> 63.9
> 63.5

95
95
95

> 65
none 10–225
none 12.6–29.6> 44.3
none 0.5–1095

BUSKULIC
2 AHMED

9595958KIM
AKRAWY
3 RILES
4 STOKER> 124 STOKER>

01B L301B L3Assumed m ± − m 0 > 8.4LL
GeVm 0 >m ± and L± → ν W
LL

Decay to massless ν’sm L − m 0 > 7 GeV
L
96S ALEP Decay to massless ν’s
94 CNTR H1 Collab. at HERA
91B AMY Massless ν assumed
90G OPAL
90 MRK2 For (m 0 -m 0 )> 0.25–0.4GeV
L
L
89 MRK2 For (m + − m 0 )= 0.4 GeV
L
L
89 MRK2 For m 0 =0.9 GeVL
88 VNS
88B TOPZ
88C CELL
87B UA185 MRKJ
83 JADE81B PLUT
81 TASS80
80B CNTR
69 RVUE

5 ABEnone 18.4–27.6 95
6> 25.595
ADACHI
none 1.5–22.095
BEHREND
7 ALBAJAR> 4190
8 ADEVA> 22.595
9> 18.0
95
BARTEL10 BERGER
none 4–14.595
11 BRANDELIK> 15.595
12> 13.
AZIMOV
13 BARBER> 16.
95
14 ROTHE> 0.490
1 ACCIARRI 96G assumes LEP result that the associated neutral heavy lepton mass > 40GeV.
2 The AHMED 94 limits are from a search for neutral and charged sequential heavy leptons
at HERA via the decay channels L− → e γ, L− → ν W − , L− → e Z ; and L0 → ν γ,L0 → e − W + , L− → ν Z , where the W decays to ℓ νℓ , or to jets, and Z decays toℓ+ ℓ− or jets.
3 RILES 90 limits were the result of a special analysis of the data in the case where the massdifference m − − m 0 was allowed to be quite small, where L0 denotes the neutrino
LL

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

into which the sequential charged lepton decays. With a slightly reduced m ± range,
Lthe mass difference extends to about 4 GeV.
4 STOKER 89 (Mark II at PEP) gives bounds on charged heavy lepton (L+ ) mass forthe generalized case in which the corresponding neutral heavy lepton (L0 ) in the SU(2)doublet is not of negligible mass.
5 ABE 88 search for L+ and L− → hadrons looking for acoplanar jets. The bound isvalid for m ν < 10 GeV.
6 ADACHI 88B search for hadronic decays giving acoplanar events with large missing energy.
Ecm ee = 52 GeV.
7 Assumes associated neutrino is approximately massless.
8 ADEVA 85 analyze one-isolated-muon data and sensitive to τ <10 nanosec. Assume
B(lepton) = 0.30. E cm = 40–47 GeV.
9 BARTEL 83 limit is from PETRA e + e − experiment with average E
cm = 34.2 GeV.
10 BERGER 81B is DESY DORIS and PETRA experiment. Looking for e + e − → L+ L− .
11 BRANDELIK 81 is DESY-PETRA experiment. Looking for e + e − → L+ L− .
12 AZIMOV 80 estimated probabilities for M + N type events in e + e − → L+ L− deducing
semi-hadronic decay multiplicities of L from e + e − annihilation data at E cm = (2/3)m L .
Obtained above limit comparing these with e + e − data (BRANDELIK 80).
13 BARBER 80B looked for e + e − → L+ L− , L → ν + X with MARK-J at DESY-PETRA.
L
14 ROTHE 69 examines previous data on µ pair production and π and K decays.

Stable Charged Heavy Lepton (L± ) MASS LIMITSVALUE (GeV)CL%

DOCUMENT ID

TECN>102.695
ACHARD
01B L3• • • We do not use the following data for averages, fits, limits, etc. • • •15 ADACHI> 28.2
95
90C TOPZ
none 18.5–42.8> 26.5none m µ –36.3

95
95
95

AKRAWY
90O OPAL
DECAMP90F ALEPSODERSTROM90 MRK2

15 ADACHI 90C put lower limits on the mass of stable charged particles with electric charge
Q satisfying 2/3 < Q/e < 4/3 and with spin 0 or 1/2. We list here the special case fora stable charged heavy lepton.

Charged Long-Lived Heavy Lepton MASS LIMITSVALUE (GeV)CL%

DOCUMENT ID

TECN

CHG

COMMENT• • • We do not use the following data for averages, fits, limits, etc. • • •>574
95
CHATRCHYAN 13AB CMS
Leptons singlet model>102.095
ABBIENDI
03L OPAL
pair produced in e + e −16> 0.1
ANSORGE73B HBC−
Long-lived
17 BUSHNIN
none 0.55–4.5
73 CNTR −Long-lived
18 BARNA
none 0.2–0.92
68 CNTR −Long-lived
18
none 0.97–1.03
BARNA
68 CNTR −Long-lived
16 ANSORGE 73B looks for electron pair production and electron-like Bremsstrahlung.
17 BUSHNIN 73 is SERPUKHOV 70 GeV p experiment. Masses assume mean life above
7 × 10−10 and 3 × 10−8 respectively. Calculated from cross section (see “ChargedQuasi-Stable Lepton Production Differential Cross Section” below) and 30 GeV muon
pair production data.
18 BARNA 68 is SLAC photoproduction experiment.

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Page 2Created: 5/31/2024 10:15

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

Doubly-Charged Heavy Lepton MASS LIMITSVALUE (GeV)CL%

DOCUMENT ID

TECNCHG• • • We do not use the following data for averages, fits, limits, etc. • • •19 CLARK
none 1–9 GeV9081 SPEC ++19 CLARK 81 is FNAL experiment with 209 GeV muons. Bounds apply to µ whichP
couples with full weak strength to muon. See also section on “Doubly-Charged Lepton
Production Cross Section.”

Doubly-Charged Lepton Production Cross Section(µ N Scattering)
VALUE (cm2 )EVTS

DOCUMENT ID

TECNCHG• • • We do not use the following data for averages, fits, limits, etc. • • •20 CLARK<6. × 10−38081 SPEC ++20 CLARK 81 is FNAL experiment with 209 GeV muon. Looked for µ+ nucleon → µ0 X,Pµ0 → µ+ µ− ν µ and µ+ n → µ++ X, µ++ → 2µ+ νµ . Above limits are for σ×BRPPP
taken from their mass-dependence plot figure 2.

REFERENCES FOR Heavy Charged Lepton Searches
CHATRCHYAN 13AB JHEP 1307 122
S. Chatrchyan et al.
Also
JHEP 2211 149 (errat.) S. Chatrchyan et al.
ABBIENDI
03L PL B572 8
G. Abbiendi et al.
ACHARD
01B PL B517 75
P. Achard et al.
ACKERSTAFF 98C EPJ C1 45
K. Ackerstaff et al.
ACCIARRI
96G PL B377 304
M. Acciarri et al.
ALEXANDER 96P PL B385 433
G. Alexander et al.
BUSKULIC
96S PL B384 439
D. Buskulic et al.
AHMED
94
PL B340 205
T. Ahmed et al.
KIM
91B IJMP A6 2583
G.N. Kim et al.
ADACHI
90C PL B244 352
I. Adachi et al.
AKRAWY90G PL B240 250
M.Z. Akrawy et al.
AKRAWY
90O PL B252 290
M.Z. Akrawy et al.
DECAMP
90F PL B236 511
D. Decamp et al.
RILES90
PR D42 1
K. Riles et al.
SODERSTROM 90
PRL 64 2980
E. Soderstrom et al.
STOKER89
PR D39 1811
D.P. Stoker et al.
ABE88
PRL 61 915
K. Abe et al.
ADACHI88B PR D37 1339
I. Adachi et al.
BEHREND
88C ZPHY C41 7
H.J. Behrend et al.
ALBAJAR
87B PL B185 241
C. Albajar et al.
ADEVA
85
PL 152B 439
B. Adeva et al.
Also
PRPL 109 131
B. Adeva et al.
BARTEL83
PL 123B 353
W. Bartel et al.
BERGER81B PL 99B 489
C. Berger et al.
BRANDELIK81
PL 99B 163
R. Brandelik et al.
CLARK81
PRL 46 299
A.R. Clark et al.
AlsoPR D25 2762
W.H. Smith et al.
AZIMOV80
JETPL 32 664
Y.I. Azimov, V.A. Khoze
Translated from ZETFP 32 677.
BARBER80B PRL 45 1904
D.P. Barber et al.
BRANDELIK80
PL 92B 199
R. Brandelik et al.
ANSORGE
73B PR D7 26
R.E. Ansorge et al.
BUSHNIN
73
NP B58 476
Y.B. Bushnin et al.
Also
PL 42B 136
S.V. Golovkin et al.
ROTHE
69
NP B10 241
K.W. Rothe, A.M. Wolsky
BARNA68
PR 173 1391
A. Barna et al.

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

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