Exclusive Rare Decay $B\to K^{\ast }\gamma$

Abstract

We show that the exclusive decay $B\to K^{\ast }\gamma$ can be related to the semileptonic decay $B\to \rho e\bar{\nu }$ using heavy-quark symmetry and $SU(3)$ flavor symmetry. A direct measurement of the $q^2$-spectrum for the semileptonic decay can provide relevant information for the exclusive rare decay.

7 pages, UTPT-92-12, IP-ASTP-14, REVTEX