Method of constraining theCP-violating phase γ from chargedBmeson decays

Gronau, Rosner, and London have presented a method of determining the CP-violating phase γ of the CKM matrix from the decays ${\mathit{B}}^{+}$→${\mathrm{\pi }}^{+}$ ${\mathit{K}}^0$ and ${\mathit{B}}^{\pm }$→${\mathit{K}}^{\pm }$ ${\mathrm{\pi }}^0$. We show that this method could provide a powerful constraint on γ even if only a weak upper limit on the CP violation is obtained. We also point out a consequence of the assumptions they make.