Determination of the B̄→D*ℓν̄ decay width and |V cb|

N. E. Adam, J. P. Alexander, C. Bebek, B. E. Berger, K. Berkelman, F. Blanc, V. Boisvert, D. G. Cassel, P. S. Drell, J. E. Duboscq, K. M. Ecklund, R. Ehrlich, L. Gibbons, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, L. Hsu, C. D. Jones, J. KandaswamyD. L. Kreinick, A. Magerkurth, H. Mahlke-Krüger, T. O. Meyer, N. B. Mistry, E. Nordberg, M. Palmer, J. R. Patterson, D. Peterson, J. Pivarski, D. Riley, A. J. Sadoff, H. Schwarthoff, M. R. Shepherd, J. G. Thayer, D. Urner, B. Valant-Spaight, G. Viehhauser, A. Warburton, M. Weinberger, S. B. Athar, P. Avery, H. Stoeck, J. Yelton, G. Brandenburg, A. Ershov, D. Y.J. Kim, R. Wilson, K. Benslama, B. I. Eisenstein

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In the standard model, the charged current of the weak interaction is governed by a unitary quark mixing matrix that also leads to CP violation. Measurement of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements is essential to searches for new physics, either through the structure of the CKM matrix, or a departure from unitarity. We determine the CKM matrix element |V cb| using a sample of 3×10 6 BB̄ events in the CLEO detector at the Cornell Electron Storage Ring. We determine the yield of reconstructed B̄ 0 →D* + ℓν̄ and B -D* 0ℓν̄ decays as a function of w, the boost of the D* in the B rest frame, and from this we obtain the differential decay rate dΓ/dw. By extrapolating dΓ/dw to w = 1, the kinematic end point at which the D* is at rest relative to the B, we extract the product |V cb|ℱ(1), where ℱ(1) is the form factor at w=1. We find |V cb|ℱ(1) = 0.0431±0.0013(stat) ±0.0018(syst). We combine |V cb|ℱ(1) with theoretical results for ℱ(1) to determine |V cb| = 0.0469±0.0014(stat) ±0.0020(syst)±0.0018(theor). We also integrate the differential decay rate over w to obtain B(B̄ 0→D * +ℓν̄ = (609±0.19±0.40)% and B(B -→D* 0ℓν̄) = (6.50±0. 20±0.43)%.

Original languageEnglish (US)
Article number032001
JournalPhysical Review D
Issue number3
StatePublished - Dec 1 2003


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