Determination of the form factors for the decayB0→D*−l+νland of the CKM matrix element|Vcb|

Author(s): Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, JP; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Tico, JG; Grauges, E; Lopez, L; Palano, A; Eigen, G; Ofte, I; Stugu, B; Sun, L; Abrams, GS; Battaglia, M; Brown, DN; Button-Shafer, J; Cahn, RN; Groysman, Y; Jacobsen, RG; Kadyk, JA; Kerth, LT; Kolomensky, YG; Kukartsev, G; Pegna, DL; Lynch, G; Mir, LM; Orimoto, TJ; Pripstein, M; Roe, NA; Ronan, MT; Tackmann, K; Wenzel, WA; Del Amo Sanchez, P; Hawkes, CM; Watson, AT; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Schroeder, T; Steinke, M; Cottingham, WN; Walker, D; Asgeirsson, DJ; Cuhadar-Donszelmann, T; Fulsom, BG; Hearty, C; Knecht, NS; Mattison, TS; McKenna, JA; Khan, A; Saleem, M; Teodorescu, L; Blinov, VE; Bukin, AD; 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; Abachi, S; Buchanan, C; Foulkes, SD; Gary, JW; Liu, F; Long, O; Shen, BC; Zhang, L; Paar, HP | Abstract: We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| and of the parameters ρ2, R1(1), and R2(1), which fully characterize the form factors for the B0→D*- +ν decay in the framework of heavy-quark effective field theory. The results, based on a selected sample of about 52800 B0→D*- +ν decays, recorded by the BABAR detector, are ρ2=1.157±0.094±0.027, R1(1)=1. 327±0.131±0.043, R2(1)=0.859±0.077±0.021, and F(1)|Vcb|=(34.7±0.4±1.0)×10-3. The first error is the statistical and the second is the systematic uncertainty. Combining these measurements with the previous BABAR measurement of the form factors, which employs a different fit technique on a partial sample of the data, we improve the statistical precision of the result, ρ2=1.191±0.048±0.028, R1(1)=1.429±0.061±0.044, R2(1)=0.827±0.038±0.022, and F(1)|Vcb|=(34.4±0.3±1.1)×10-3. Using lattice calculations for the axial form factor F(1), we extract |Vcb|=(37.4±0. 3±1.2±1.41.2)×10-3, where the third error is due to the uncertainty in F(1). We also present a measurement of the exclusive branching fraction, B=(4.69±0.04±0.34)%. © 2008 The American Physical Society.