Radiative rare $B$ decays revisited

Abstract

We reexamine contributions of higher $K$-resonances to the radiative rare decays $b\rar s\gamma$ in the limit where both $b$- and $s$-quark are considered heavy. Using the non-relativistic quark model, and the form factor definitions consistent with the HQET covariant trace formalism, we find significant disagreement with previous work which also used heavy quark symmetry, and excellent agreement with experimental results. In particular, the two largest fractions of the inclusive $b\rar s\gamma$ branching ratio are found to be $(16.8\pm 6.4)\%$ for $B\rar K^{*}(892)\gamma$ and $(6.2\pm 2.9)\%$ for $B\rar K_{2}^{*}(1430)\gamma$ decays. We also compare the contribution from the radiative decays into the eight $K$-meson states to the inclusive experimental $b\rar s\gamma$ mass distribution.