Search for B+→ℓ+νℓrecoiling against B-→ℓ-ν̄X

Author(s): Aubert, B; Karyotakis, Y; Lees, JP; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V; Garra Tico, J; Grauges, E; Martinelli, M; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Battaglia, M; Brown, DN; Hooberman, B; Kerth, LT; Kolomensky, YG; Lynch, G; Osipenkov, IL; Tackmann, K; Tanabe, T; Hawkes, CM; Soni, N; Watson, AT; Koch, H; Schroeder, T; Asgeirsson, DJ; Hearty, C; Mattison, TS; McKenna, JA; Barrett, M; Khan, A; Randle-Conde, A; Blinov, VE; Bukin, AD; Buzykaev, AR; Druzhinin, VP; Golubev, VB; Onuchin, AP; Serednyakov, SI; Skovpen, YI; Solodov, EP; Todyshev, KY; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, AJ; Lund, P; Mandelkern, M; Martin, EC; Stoker, DP; Atmacan, H; Gary, JW; Liu, F; Long, O; Vitug, GM; Yasin, Z; Sharma, V; Campagnari, C; Hong, TM; Kovalskyi, D; Mazur, MA; Richman, JD; Beck, TW; Eisner, AM; Heusch, CA; Kroseberg, J; Lockman, WS; Martinez, AJ; Schalk, T; Schumm, BA; Seiden, A; Wang, L; Winstrom, LO; Cheng, CH; Doll, DA; Echenard, B; Fang, F; Hitlin, DG; Narsky, I; Ongmongkolkul, P | Abstract: We present a search for the decay B+→l+νl(l=τ,μ,ore) in (458.9±5.1)×106 BB pairs recorded with the BABAR detector at the PEP-II B-factory. We search for these B decays in a sample of B+B-events where one B-meson is reconstructed as B-→D0l-νX. Using the method of Feldman and Cousins, we obtain B(B+→τ+ντ)=(1.7±0.8±0.2) ×10-4, which excludes zero at 2.3σ. We interpret the central value in the context of the standard model and find the B meson decay constant to be fB2=(62±31)×103MeV2. We find no evidence for B+→e+νe and B+→μ+ν μ and set upper limits at the 90% C.L. B(B+→e+νe)l0.8×10-5 and B(B+→μ+νμ)l1.1×10-5. © 2010 The American Physical Society.