Measurement of the $B \to \pi \ell \nu$ Branching Fraction and Determination of $|V_{ub}|$ with Tagged B Mesons

Abstract : We report a measurement of the B -> pi l nu branching fraction based on 211 fb-1 of data collected with the BABAR detector. We use samples of B0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay, and combine the results assuming isospin symmetry to obtain BF(B0 -> pi- l+ nu) = (1.33 +/- 0.17(stat) +/- 0.11(syst)) x 10^-4. We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |Vub| by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find |Vub| = (4.5 +/- 0.5(stat) +/- 0.3(syst) +0.7/-0.5(FF)) x 10^-3, where the last error is due to the normalization of the form factor.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00113855
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Submitted on : Tuesday, January 16, 2007 - 4:01:58 PM
Last modification on : Sunday, June 20, 2021 - 3:35:03 AM

Citation

B. Aubert, R. Barate, M. Bona, D. Boutigny, F. Couderc, et al.. Measurement of the $B \to \pi \ell \nu$ Branching Fraction and Determination of $|V_{ub}|$ with Tagged B Mesons. Physical Review Letters, American Physical Society, 2006, 97, pp.211801. ⟨10.1103/PhysRevLett.97.211801⟩. ⟨in2p3-00113855⟩

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