First evidence for the decay Bs -> mu+ mu-
R. Aaij
,
S. Barsuk
(1)
,
O. Callot
(1)
,
J. He
(1)
,
B. Jean-Marie
(1)
,
J. Lefrançois
(1)
,
F. Machefert
(1)
,
A. Martin Sanchez
(1)
,
Marie Nicol
(1)
,
P. Robbe
(1)
,
M.-H. Schune
(1)
,
B. Viaud
(1)
,
I. Videau
(1)
,
E. Ben-Haim
(2)
,
M. Benayoun
(2)
,
P. David
(2)
,
L. del Buono
(2)
,
A. Martens
(2)
,
Ziad Zj Ajaltouni
(3)
,
O. Deschamps
(3)
,
E. Cogneras
(3)
,
I. El Rifai
(3)
,
Pierre Henrard
(3)
,
M. Hoballah
(3)
,
Marwa Jahjah-Hussein
(3)
,
R. Lefèvre
(3)
,
L. Li Gioi
(3)
,
S. Monteil
(3)
,
V. Niess
(3)
,
Pascal Perret
(3)
,
Diego Alejandro Roa Romero
(3)
,
Krzysztof Grzegorz Sobczak
(3)
,
C. Adrover
(4)
,
E. Aslanides
(4)
,
J. Cogan
(4)
,
R. Legac
(4)
,
O. Leroy
(4)
,
G. Mancinelli
(4)
,
E. Maurice
(4)
,
M. Perrin-Terrin
(4)
,
M. Sapunov
(4)
,
J. Serrano
(4)
,
A. Tsaregorodtsev
(4)
,
I. de Bonis
(5)
,
D. Decamp
(5)
,
Ph. Ghez
(5)
,
P. Hopchev
(5)
,
J.-P. Lees
(5)
,
I.V. Machikhiliyan
(5)
,
M.-N. Minard
(5)
,
B. Pietrzyk
(5)
,
W. Qian
(5)
,
S. t'Jampens
(5)
,
V. Tisserand
(5)
,
E. Tournefier
(5)
R. Aaij
- Function : Author
J. He
- Function : Author
- PersonId : 756138
- ORCID : 0000-0001-8179-417X
L. del Buono
- Function : Author
- PersonId : 742055
- IdHAL : luigi-del-buono
- IdRef : 253135834
A. Martens
- Function : Author
- PersonId : 738690
- IdHAL : aurelien-martens
Ziad Zj Ajaltouni
- Function : Author
- PersonId : 903794
O. Deschamps
- Function : Author
- PersonId : 12089
- IdHAL : olivier-deschamps
- ORCID : 0000-0002-7047-6042
- IdRef : 161447368
E. Cogneras
- Function : Author
- PersonId : 743220
- IdHAL : eric-cogneras
- ORCID : 0000-0002-8933-9427
Pierre Henrard
- Function : Author
- PersonId : 829303
M. Hoballah
- Function : Author
- PersonId : 1174785
- IdHAL : mostafa-adam-hoballah-hobart
Pascal Perret
- Function : Author
- PersonId : 739797
- IdHAL : pascal-perret
- ORCID : 0000-0002-5732-4343
Diego Alejandro Roa Romero
- Function : Author
- PersonId : 769524
- IdRef : 172096839
J. Cogan
- Function : Author
- PersonId : 750510
- IdHAL : julien-cogan
- ORCID : 0000-0001-7194-7566
- IdRef : 078779014
O. Leroy
- Function : Author
- PersonId : 171866
- IdHAL : olivier-leroy
- ORCID : 0000-0002-2589-240X
- IdRef : 169871835
M. Perrin-Terrin
- Function : Author
- PersonId : 741779
- IdHAL : perrin-terrin
- ORCID : 0000-0002-3568-1956
- IdRef : 179269666
J. Serrano
- Function : Author
- PersonId : 175327
- IdHAL : justine-serrano
- ORCID : 0000-0003-2489-7812
- IdRef : 127525521
S. t'Jampens
- Function : Author
- PersonId : 736045
- IdHAL : stephane-tjampens
- ORCID : 0000-0003-4249-6641
Abstract
A search for the rare decays Bs->mu+mu- and B0->mu+mu- is performed using data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise 1.1 fb^-1 of proton-proton collisions at sqrt{s} = 8 TeV and 1.0 fb^-1 at sqrt{s}=7 TeV. We observe an excess of Bs -> mu+ mu- candidates with respect to the background expectation. The probability that the background could produce such an excess or larger is 5.3 x 10^-4 corresponding to a signal significance of 3.5 standard deviations. A maximum-likelihood fit gives a branching fraction of BR(Bs -> mu+ mu-) = (3.2^{+1.5}_{-1.2}) x 10^-9, where the statistical uncertainty is 95% of the total uncertainty. This result is in agreement with the Standard Model expectation. The observed number of B0 -> mu+ mu- candidates is consistent with the background expectation, giving an upper limit of BR(B0 -> mu+ mu-) < 9.4 x 10^-10 at 95% confidence level.