Abstract
We present an analysis of exclusive charmless semileptonic -meson decays based on pairs recorded with the BABAR detector at the resonance. We select four event samples corresponding to the decay modes , , , and and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two samples, and similarly the two samples, and measure the branching fractions and , where the errors are statistical and systematic. We compare the measured distribution in , the momentum transfer squared, with predictions for the form factors from QCD calculations and determine the Cabibbo-Kobayashi-Maskawa matrix element . Based on the measured partial branching fraction for in the range and the most recent QCD light-cone sum-rule calculations, we obtain , where the errors refer to the experimental and theoretical uncertainties. From a simultaneous fit to the data over the full range and the FNAL/MILC lattice QCD results, we obtain from , where the error is the combined experimental and theoretical uncertainty.
19 More- Received 18 May 2010
DOI:https://doi.org/10.1103/PhysRevD.83.032007
© 2011 American Physical Society