Weak Phase $γ$ From Ratio of $B \to K π$ Rates

Abstract

The ratio of partial decay rates for charged and neutral $B$ mesons to $K π$ final states provides information on the weak phase $γ\equiv {\rm Arg} (V_{ub}^*)$ when augmented with information on the CP-violating asymmetry in the $K^\pm π^\mp$ mode. The requirements for a useful determination of $γ$ are examined in the light of present information about the decays $B^0 \to K^+ π^-$, $B^+ \to K^0 π^+$, and the corresponding charge-conjugate modes. The effects of electroweak penguins and rescattering corrections are noted, and proposals are made for estimating and measuring their importance.