Measurement of the B+ --> omega l+ nu branching fraction with semileptonically tagged B mesons

TL;DR

This paper measures the branching fraction of the B+ --> omega l+ nu decay using semileptonically tagged B mesons, providing experimental data that tests theoretical form factor predictions.

Contribution

First measurement of the B+ --> omega l+ nu branching fraction with semileptonic tagging, including q2-dependent partial branching fractions for comparison with theory.

Findings

BF(B+ --> omega l+ nu) = (1.35 +/- 0.21 +/- 0.11) x 10^{-4}

Partial branching fractions measured in three q2 bins

Results compared to theoretical form factor predictions

Abstract

We report a measurement of the branching fraction of the exclusive charmless semileptonic decay B+ --> omega l+ nu, where l is either an electron or a muon. We use samples of B+ mesons tagged by a reconstructed charmed semileptonic decay of the other B meson in the event. The measurement is based on a dataset of 426.1 fb-1 of e+e- collisions at a center-of-mass energy of 10.58 GeV recorded with the BABAR detector at the PEP-II asymmetric-energy e+e- storage rings. We measure a branching fraction of BF(B+ --> omega l+ nu) = (1.35 +/- 0.21 +/- 0.11) x 10(-4), where the uncertainties are statistical and systematic, respectively. We also present measurements of the partial branching fractions in three bins of q2, the invariant-mass squared of the lepton-neutrino system, and we compare them to theoretical predictions of the form factors.