Abstract
We report the results of a study of the exclusive charmless semileptonic decay, , undertaken with approximately pairs collected at the resonance with the BABAR detector. The analysis uses events in which the signal decays are reconstructed with an innovative loose neutrino reconstruction technique. We obtain partial branching fractions in 12 bins of , the momentum transfer squared, from which we extract the form-factor shape and the total branching fraction . Based on a recent unquenched lattice QCD calculation of the form factor in the range , we find the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element to be , where the last uncertainty is due to the normalization of the form factor.
- Received 12 December 2006
DOI:https://doi.org/10.1103/PhysRevLett.98.091801
©2007 American Physical Society