B to light meson transition form factors calculated in perturbative QCD approach

We calculate the $B\to P$, $B\to V$ (P: light pseudoscalar meson, V light vector meson) form factors in the large-recoil limit in perturbative QCD approach, including both the vector (axial vector) and tensor operators. In general there are two leading components $\phi_B$ and $\bar{\phi}_B$ for $B$ meson wave functions. We consider both contributions of them. Sudakov effects ($k_{\perp}$ and threshold resummation) are included to regulate the soft end-point singularity. By choosing the hard scale as the maximum virtualities of internal particles in the hard $b$-quark decay amplitudes, Sudakov factors can effectively suppress the long-distance soft contribution. Hard contribution can be dominant in these approaches.Comment: 21 pages, with 2 figure

Small Covers over Prisms

In this paper we calculate the number of equivariant diffeomorphism classes of small covers over a prism