Laboratoire d'Annecy-le-Vieux de Physique des Particules, Université de Savoie, CNRS/IN2P3, F-74941 Annecy-Le-Vieux, France.
Phys Rev Lett. 2010 Jan 8;104(1):011802. doi: 10.1103/PhysRevLett.104.011802. Epub 2010 Jan 5.
We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V(cb)| and the form-factor slope rho2 in B --> Dl- nu(l) decays based on 460x10(6) BB events recorded at the Upsilon(4S) resonance with the BABAR detector. B --> Dl- nu(l) decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure B(B- --> D0 l- nu(l))/B(B- --> Xl- nu(l)) = (0.255+/-0.009+/-0.009) and B(B0 --> D+ l- nu(l))/B(B0 --> Xl- nu(l)) = (0.230+/-0.011+/-0.011), along with the differential decay distribution in B --> Dl- nu(l) decays. We then determine G(1)|V(cb)| = (42.3+/-1.9+/-1.4)x10(-3) and rho2 = 1.20+/-0.09+/-0.04, where G(1) is the hadronic form factor at the point of zero recoil.
我们呈现了一项在 Upsilon(4S) 共振能区，使用 BABAR 探测器，通过 460x10(6) BB 事例，对 Cabibbo-Kobayashi-Maskawa 矩阵元 |V(cb)| 和 B --> Dl- nu(l) 衰变中的形状因子斜率 rho2 的测量结果。通过对第二个 B 介子的强子衰变被完全重建的事例，我们挑选出 B --> Dl- nu(l) 衰变。我们测量到 B(B- --> D0 l- nu(l))/B(B- --> Xl- nu(l)) = (0.255+/-0.009+/-0.009) 和 B(B0 --> D+ l- nu(l))/B(B0 --> Xl- nu(l)) = (0.230+/-0.011+/-0.011)，以及 B --> Dl- nu(l) 衰变的微分衰变分布。然后，我们确定 G(1)|V(cb)| = (42.3+/-1.9+/-1.4)x10(-3) 和 rho2 = 1.20+/-0.09+/-0.04，其中 G(1) 是在零反冲点的强子形状因子。
