Evidence of the purely leptonic decay B-→τ-ν̄τ

K Ikado; K Abe; K Abe; I Adachi; H Aihara; K Akai; M Akemoto; D Anipko; K Arinstein; V Aulchenko; T Aushev; T Aziz; AM Bakich; V Balagura; M Barbero; A Bay; I Bedny; K Belous; U Bitenc; I Bizjak; A Bondar; A Bozek; M Bračko; TE Browder; P Chang; A Chen; WT Chen; Y Choi; S Cole; J Dalseno; M Danilov; M Dash; S Eidelman; D Epifanov; J Flanagan; S Fratina; K Furukawa; N Gabyshev; T Gershon; A Go; G Gokhroo; B Golob; A Gorišek; H Ha; J Haba; K Hara; T Hara; NC Hastings; K Hayasaka; H Hayashii; M Hazumi; L Hinz; T Hokuue; Y Hoshi; S Hou; WS Hou; N Iida; T Iijima; A Imoto; K Inami; A Ishikawa; H Ishino; R Itoh; M Iwasaki; Y Iwasaki; T Kamitani; JH Kang; SU Kataoka; N Katayama; H Kawai; T Kawasaki; H Kichimi; E Kikutani; HJ Kim; HO Kim; K Kinoshita; H Koiso; S Korpar; P Križan; P Krokovny; R Kulasiri; R Kumar; CC Kuo; A Kuzmin; YJ Kwon; JS Lange; G Leder; J Lee; T Lesiak; A Limosani; SW Lin; D Liventsev; D Marlow; T Matsumoto; A Matyja; S McOnie; S Michizono; T Mimashi; W Mitaroff; K Miyabayashi

Journal article

Evidence of the purely leptonic decay B-→τ-ν̄τ

K Ikado, K Abe, K Abe, I Adachi, H Aihara, K Akai, M Akemoto, D Anipko, K Arinstein, V Aulchenko, T Aushev, T Aziz, AM Bakich, V Balagura, M Barbero, A Bay, I Bedny, K Belous, U Bitenc, I Bizjak Show all

Physical Review Letters | AMER PHYSICAL SOC | Published : 2006

DOI: 10.1103/PhysRevLett.97.251802

Abstract

We present the first evidence of the decay B-→τ-ν̄τ, using 414fb-1 of data collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B-→τ-ν̄τ)=(1.79-0.49+0.56(stat) -0.51+0.46(syst))×10-4. This implies that fB=0.229-0.031+0.036(stat)-0. 037+0.034(syst)GeV and is the first direct measurement of this quantity. © 2006 The American Physical Society.