Measurement of the B0s→μ+μ− branching fraction and effective lifetime and search for B0→μ+μ− decays
R. Aaij
,
L. Beaucourt
(1)
,
M. Chefdeville
(1)
,
D. Decamp
(1)
,
N. Déléage
(1)
,
P. Ghez
(1)
,
J.-F. Marchand
(1)
,
M.-N. Minard
(1)
,
B. Pietrzyk
(1)
,
S. t'Jampens
(1)
,
V. Tisserand
(1)
,
E. Tournefier
(1)
,
Z. Xu
(1)
,
J. Arnau Romeu
(2)
,
E. Aslanides
(2)
,
J. Cogan
(2)
,
K. De Bruyn
(2)
,
R. Legac
(2)
,
O. Leroy
(2)
,
G. Mancinelli
(2)
,
M. Martin
(2)
,
M. Perrin-Terrin
(2)
,
J. Serrano
(2)
,
A. Tayduganov
(2)
,
A. Tsaregorodtsev
(2)
R. Aaij
- Fonction : Auteur
M. Chefdeville
- Fonction : Auteur
- PersonId : 741874
- IdHAL : maximilien-chefdeville
- ORCID : 0000-0002-6553-6493
S. t'Jampens
- Fonction : Auteur
- PersonId : 736045
- IdHAL : stephane-tjampens
- ORCID : 0000-0003-4249-6641
J. Cogan
- Fonction : Auteur
- PersonId : 750510
- IdHAL : julien-cogan
- ORCID : 0000-0001-7194-7566
- IdRef : 078779014
O. Leroy
- Fonction : Auteur
- PersonId : 171866
- IdHAL : olivier-leroy
- ORCID : 0000-0002-2589-240X
- IdRef : 169871835
M. Perrin-Terrin
- Fonction : Auteur
- PersonId : 741779
- IdHAL : perrin-terrin
- ORCID : 0000-0002-3568-1956
- IdRef : 179269666
J. Serrano
- Fonction : Auteur
- PersonId : 175327
- IdHAL : justine-serrano
- ORCID : 0000-0003-2489-7812
- IdRef : 127525521
Résumé
A search for the rare decays B0s→μ+μ− and B0→μ+μ− is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4 fb−1. An excess of B0s→μ+μ− decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(B0s→μ+μ−)=(3.0±0.6+0.3−0.2)×10−9, where the first uncertainty is statistical and the second systematic. The first measurement of the B0s→μ+μ− effective lifetime, τ(B0s→μ+μ−)=2.04±0.44±0.05 ps, is reported. No significant excess of B0→μ+μ− decays is found and a 95 % confidence level upper limit, B(B0→μ+μ−)<3.4×10−10, is determined. All results are in agreement with the Standard Model expectations.