Final State Interaction Effects on $\gamma$ from $B\to DK$

Abstract

The implications of a negligible annihilation contribution in $B\to DK$ decays are reanalyzed and are shown to lead to no new constraints on the weak phase $\gamma$ from color-allowed $B^{\pm }\to D{K}^{\pm }$ decays. A test of negligible annihilation is proposed in $B^{+}\to D^{+}{K}^0$ (or $B^{+}\to D^{+}{K}^{\ast 0}$), and an application is presented in which $\gamma$ can be determined from these processes (or corresponding $B\to D{K}^{\ast }$ decays) supplemented with isospin-related neutral $B$ decays.