The role of Bs→Kπ in determining the weak phase γ

The decay rates for B0→K+π−, B+→K0π+, and the charge-conjugate processes were found to provide information on the weak phase γ≡Arg(Vub∗) when the ratio r of weak tree and penguin amplitudes was taken from data on B→ππ or semileptonic B→π decays. We show here that the rates for Bs→K−π+ and B̄s→K+π− can provide the necessary information on r, and estimate the statistical accuracy of forthcoming measurements at the Fermilab Tevatron.