Evidence of B+->tau nu decays with hadronic B tags
J.P. Lees
(1)
,
V. Poireau
(1)
,
V. Tisserand
(1)
,
N. Arnaud
(2)
,
M. Davier
(2)
,
D. Derkach
(2)
,
G. Grosdidier
(2)
,
F. Le Diberder
(2)
,
A.M. Lutz
(2)
,
B. Malaescu
(3)
,
P. Roudeau
(2)
,
M.H. Schune
(2)
,
A. Stocchi
(2)
,
G. Wormser
(2)
,
D. Bernard
(4)
,
M. Verderi
(4)
,
S. Emery
(5)
,
G. Hamel de Monchenault
(5)
,
G. Vasseur
(5)
,
Ch. Yèche
(5)
,
S. Akar
(3)
,
E. Ben-Haim
(3)
,
M. Bomben
(3)
,
G.R. Bonneaud
(3)
,
H. Briand
(3)
,
G. Calderini
(3)
,
J. Chauvau
(3)
,
O. Hamon
(3)
,
Ph. Leruste
(3)
,
G. Marchiori
(3)
,
J. Ocariz
(3)
,
S. Sitt
(3)
N. Arnaud
- Function : Author
- PersonId : 16841
- IdHAL : nicolas-arnaud
- ORCID : 0000-0001-6589-8673
G. Vasseur
- Function : Author
- PersonId : 745439
- IdHAL : georges-vasseur
M. Bomben
- Function : Author
- PersonId : 1380362
- ORCID : 0000-0002-9807-861X
- IdRef : 242005462
G. Calderini
- Function : Author
- PersonId : 10608
- IdHAL : giovanni-calderini
- ORCID : 0000-0002-9495-9145
- IdRef : 172243211
G. Marchiori
- Function : Author
- PersonId : 741274
- IdHAL : giovanni-marchiori
- ORCID : 0000-0003-2655-7643
- IdRef : 180997203
Abstract
We present a search for the decay B+ -->tau+ nu using 467.8 x 10^6 B B pairs collected at the Y(4S) resonance with the BaBar detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in the hadronic decay modes (B- --> D(*)0 X- and B- --> J/\psi X-). We examine the rest of the event to search for a B+ --> tau+ nu decay. We identify the tau+ lepton in the following modes: tau+ --> e+ nu nu, tau+ --> mu+ nu nu, tau+ --> pi+ nu, and tau+ --> rho+ nu. We find an excess of events with respect to the expected background, which excludes the null signal hypothesis at the level of 3.8 sigma (including systematic uncertainties) and corresponds to a branching fraction central value of B(B+ --> tau+ nu)=(1.83^{+0.53}_{-0.49}(stat.) +/- 0.24 (syst.)) x 10^-4.