# ICHEP2012

4-11 July 2012
Melbourne Convention and Exhibition Centre
Australia/Melbourne timezone
ICHEP2012 - 36th International Conference for High Energy Physics

## Charmless semileptonic B decays at BaBar

5 Jul 2012, 10:15
15m
Room 220 (Melbourne Convention and Exhibition Centre)

### Room 220

#### Melbourne Convention and Exhibition Centre

Melbourne Australia
Parallel Sessions Track 7. CP Violation, CKM, Rare Decays, Meson Spectroscopy

### Speaker

Prof. Abner Soffer (Tel Aviv University (IL))

### Description

The q^2 dependence of exclusive semileptonic form factors may be used to test standard-model theoretical calculations, and the total branching fractions provide a measure of the CKM matrix element V_ub. We report on measurements of the differential branching fractions of the exclusive semileptonic decays B-->pi l nubar, B-->eta l nubar, B-->eta’ l nubar, and B-->omega l nubar as a function of q^2. We report the branching fractions for these decays and determine |V_ub| using theoretical predictions from sum-rule and unquenched-lattice QCD calculations. We report a comprehensive study of the partial branching fractions for inclusive b --> u l nbar transitions using decays recoiling against a fully reconstructed B meson performed with the full BABAR data sample. The partial branching fractions are measured in seven overlapping regions of phase space using different kinematic cuts to suppress the much more abundant b --> c l nubar decays. Values of the CKM element |V_{ub}| are determined using four independent calculations of the partial decay rates. The most precise result is obtained from a two-dimensional fit to the m_X vs. q^2 distributions, with no kinematic restriction other than requiring the lepton momentum to be greater than 1 GeV. Furthermore, we report a new limit on weak annihilation, studied using the isospin conjugated decays of the neutral and charged B mesons.

### Primary authors

Prof. Abner Soffer (Tel Aviv University (IL)) Florian Urs Bernlochner (University of Victoria (CA))

 Slides