B. Aubert, BABAR Collaboration
Published 2004-08-10Version 1
We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| based on a sample of about 53,700 B0bar --> D*+ l- nubar_l decays observed by the BaBar detector. We obtain the branching fraction averaged over l = e, mu, BR(B0bar --> D*+ l- nubar_l) = (4.90 +- 0.07(stat.) +0.36-0.35(syst.))%. We measure the differential decay rate as a function of w, the relativistic boost gamma of the D*+ in the B0bar rest frame. By extrapolating dGamma/dw to the kinematic limit w --> 1, we extract the product of |Vcb| and the axial form factor A_1(w=1). We combine this measurement with a lattice QCD calculation of A_1(w=1) to determine |Vcb| = (38.7 +- 0.3(stat.) +- 1.7(syst.) +1.5-1.3(theory)) * 10^-3.
Comments: 8 pages, 4 postscript figures, contributed to ICHEP'04, 32nd International Conference on High Energy Physics, 8/16 - 8/22/2004, Beijing, China. Submitted to Phys. Rev. D (Rapid Communications)
Journal: Phys.Rev.D71:051502,2005
Measurement of Br(Bbar -> D+l-nubar) and Determination of |Vcb|
Measurement of the inclusive semileptonic branching fraction of B mesons and |Vcb|
Measurement of the decay $B\to D\ellĪ½_\ell$ in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$
