Determination of the Branching Fraction for B --> Xc l nu Decays and of |Vcb| from Hadronic-Mass and Lepton-Energy Moments

TL;DR

This paper measures the inclusive B --> Xc l nu branching fraction and the CKM matrix element |Vcb| by analyzing moments of hadronic-mass and lepton-energy distributions in semileptonic B decays, using data from the BABAR detector.

Contribution

It provides a new simultaneous fit method to extract |Vcb| and heavy-quark parameters from distribution moments, incorporating higher-order HQE corrections.

Findings

BR_cenu = (10.61 +- 0.16)%

|Vcb| = (41.4 +- 0.8) x 10^-3

Results include experimental, HQE, and theoretical uncertainties.

Abstract

We determine the inclusive B --> Xc l nu branching fraction, the CKM matrix element |Vcb|, and other heavy-quark parameters from a simultaneous fit to moments of the hadronic-mass and lepton-energy distributions in semileptonic B-meson decays, measured as a function of the lower limit on the lepton energy, using data recorded with the BABAR detector. Using Heavy Quark Expansions (HQEs) to order 1/mb^3, we extract BR_cenu=(10.61 +- 0.16(exp) +- 0.06(HQE))% and |Vcb| = (41.4 +- 0.4(exp) +- 0.4(HQE) +- 0.6(th)) 10^-3. The stated errors refer to the experimental, HQE, and additional theoretical uncertainties.