Semileptonic decays in the “PQCD+Lattice” approach *
Xue-Qing Hu, Su-Ping Jin, Zhen-Jun Xiao
Abstract
Abstract We study the semileptonic decays using the PQCD factorization approach with the newly defined distribution amplitudes of the meson and a new kind of parametrization for extrapolating the form factors which takes into account the recent lattice QCD results. We find the following main results: (a) the PQCD predictions of the branching ratios of the decays are smaller by about 5%-16% when the lattice results are taken into account in the extrapolation of the relevant form factors; (b) the PQCD predictions of the ratio and of the longitudinal polarization are , and ; and (c) after including the lattice results, the theoretical predictions slightly change: , , and . The theoretical predictions of agree with the measurements within the errors. The other predictions could be tested by the LHCb experiment in the near future.