Transition form factors of B decays into p-wave axial-vector mesons in the perturbative QCD approach

The B-u,B-d,B-s -> V, A form factors are studied in the perturbative QCD approach (V, A denote a vector meson and two kinds of p-wave axial-vector mesons: P-3(1) and P-1(1) states, respectively). The form factors are directly studied in the large recoiling region and extrapolated to the whole kinematic region within the dipole parametrization. Adopting decay constants with different signs for the two kinds of axial vectors, we find that the two kinds of B -> A form factors have the same sign. The two strange mesons K-1A and K-1B mix with each other via the SU(3) symmetry breaking effect. In order to reduce the ambiguities in the mixing angle between K-1A and K-1B, we propose a model-independent way that utilizes the B decay data. Most of the branching fractions of the semilteptonic B -> Al (nu) over bar (l) decays are of the order 10(-4), which still need experimental tests in the ongoing and forthcoming experiments.