Applicability of Heavy Quark Effective Theory to the Radiative Decay $B\to K^* + \gamma$

Abstract

In the context of the observed decay $B \rightarrow K^* \gamma$ the applicability of the Heavy Quark Effective Theory (HQET), treating both b and s as heavy quarks, is examined. We show that the heavy s-quark approximation, as can be found in the literature, is not reliable.