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

The ratio of partial decay rates for charged and neutral B mesons to $K \pi$ final states provides information on the weak phase $\gamma \equiv Arg (V_{ub}^*)$ when augmented with information on the CP-violating asymmetry in the $K^\pm \pi^\mp$ mode. The statistical requirements for a useful determination of $\gamma$ and certain systematic uncertainties are examined in the light of present information about the decays $B^0 \to K^+ \pi^-$, $B^+ \to K^0 \pi^+$, and the corresponding charge-conjugate modes.