학술논문
Measurement of the semileptonic decays B¯→Dτ-ν¯τ and B¯→D*τ-ν¯τ
Document Type
article
Author
Aubert, B; Bona, M; Karyotakis, Y; Lees, JP; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V; Tico, J Garra; Grauges, E; Lopez, L; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Abrams, GS; Battaglia, M; Brown, DN; Jacobsen, RG; Kerth, LT; Kolomensky, Yu G; Lynch, G; Osipenkov, IL; Ronan, MT; Tackmann, K; Tanabe, T; Hawkes, CM; Soni, N; Watson, AT; Koch, H; Schroeder, T; Asgeirsson, DJ; Fulsom, BG; Hearty, C; Mattison, TS; McKenna, JA; Barrett, M; Khan, A; Blinov, VE; Bukin, AD; Buzykaev, AR; Druzhinin, VP; Golubev, VB; Onuchin, AP; Serednyakov, SI; Skovpen, Yu I; Solodov, EP; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, AJ; Lund, P; Mandelkern, M; Martin, EC; Stoker, DP; Abachi, S; Buchanan, C; Atmacan, H; Gary, JW; Liu, F; Long, O; Vitug, GM; Yasin, Z; Zhang, L; Sharma, V; Campagnari, C; Hong, TM; Kovalskyi, D; Mazur, MA; Richman, JD; Beck, TW; Eisner, AM; Flacco, CJ; Heusch, CA; Kroseberg, J; Lockman, WS; Martinez, AJ; Schalk, T; Schumm, BA; Seiden, A; Wilson, MG; Winstrom, LO; Cheng, CH; Doll, DA; Echenard, B; Fang, F; Hitlin, DG; Narsky, I; Piatenko, T; Porter, FC; Andreassen, R; Mancinelli, G; Meadows, BT; Mishra, K; Sokoloff, MD; Bloom, PC; Ford, WT
Source
Physical Review D. 79(9)
Subject
Language
Abstract
We present measurements of the semileptonic decays B-→D0τ- ν̄τ, B-→D*0τ-ν̄τ, B̄0→D+τ- ν̄τ, and B̄0→D*+τ-ν̄τ, which are sensitive to non-standard model amplitudes in certain scenarios. The data sample consists of 232×106Υ(4S)→BB̄ decays collected with the BABAR detector at the PEP-II e+e- collider. We select events with a D or D* meson and a light lepton (=e or μ) recoiling against a fully reconstructed B meson. We perform a fit to the joint distribution of lepton momentum and missing mass squared to distinguish signal B̄→D(*) τ-ν̄τ(τ-→-ν̄ντ) events from the backgrounds, predominantly B̄→D(*)-ν̄. We measure the branching-fraction ratios R(D)B(B̄→Dτ-ν̄τ)/ B(B̄→D-ν̄) and R(D*)B(B̄→D*τ- ν̄τ)/B(B̄→D*-ν̄) and, from a combined fit to B- and B̄0 channels, obtain the results R(D)=(41.6±11.7±5.2) % and R(D*)=(29.7±5.6±1.8)%, where the uncertainties are statistical and systematic. Normalizing to measured B-→D(*)0- ν̄ branching fractions, we obtain B(B̄→Dτ-ν̄τ) =(0.86±0.24±0.11±0.06)% and B(B̄→D*τ- ν̄τ)=(1.62±0.31±0.10±0.05)%, where the additional third uncertainty is from the normalization mode. We also present, for the first time, distributions of the lepton momentum, |p*|, and the squared momentum transfer, q2. © 2009 The American Physical Society.