Determination of |Vub| in inclusive semileptonic B meson decays

TL;DR

This paper reports a preliminary measurement of the CKM matrix element |Vub| from inclusive semileptonic B decays, using data from the BaBar detector, with a detailed analysis of decay kinematics and theoretical inputs.

Contribution

It introduces a new measurement of |Vub| based on a novel analysis of semileptonic B decays with improved background suppression and theoretical modeling.

Findings

|Vub| measured as (4.57 +/- 0.21 +/- 0.25 +/- 0.34 +0.59/-0.29 +/- 0.22) x 10^{-3}

Partial branching fraction determined in a specific q^2-E_e region

Uncertainties include statistical, detector, background, shape function, and theoretical modeling

Abstract

We present a preliminary determination of the CKM matrix element |Vub| based on the analysis of semileptonic B decays from a sample of 88 million Upsilon(4S) decays collected with the BaBar detector at the e+e- storage ring. Charmless semileptonic B decays are selected using the electron energy E_e and the invariant mass q^2 of the electron-neutrino pair. The neutrino momentum is inferred from a measurement of the visible energy and momentum in the detector and knowledge of the e+e- beam momenta. The partial branching fraction is determined in a region of the q^2-E_e plane where semileptonic B decays to charm are highly suppressed. The total charmless semileptonic branching fraction is extracted using a theoretical calculation based on the heavy quark expansion. Preliminary results yield |Vub| = (4.57 +/- 0.21 +/- 0.25 +/- 0.34 +0.59/-0.29 +/- 0.22) x 10^{-3} where the uncertainties are from statistics (data and MC), detector modeling, background modeling, the shape function, and the heavy quark operator product expansion, respectively.