Weak phases $γ$ and $α$ from $B^+$, or $B^0$ and $B_s$ decays

Abstract

An improved flavor SU(3) method is presented for determining the weak angle $γ$ of the unitarity triangle using decay rates for $B^+\to Kπ, B^+\to K^+\bar K^0$ and $B^+\to π^+η$ (or $B^0\to Kπ$ and $B_s\to K π$), their CP-conjugate modes and the CP-averaged rate for $B^\pm\toπ^\pmπ^{0}$. Rescattering (color-suppressed) contribution in $B^+(B^0)\to Kπ$, for which an improved bound is obtained, is subtracted away. The only significant SU(3) breaking effects are accounted for in the factorization approximation of tree amplitudes. The weak angle $α$ is obtained as a byproduct.