Determining the Weak Phase γ in the Presence of Rescattering

We suggest a new technique to determine the CKM phase γ without neglecting the (soft) final state rescattering effects. We use (time integrated) B meson decay rates to π's and K's. A set of 5 ∆S = 0 (or 1 ∆S = 0 and 4 ∆S = 1) decay rates is used to compute the strong phases and magnitudes of the tree level and penguin contributions as functions of γ. These are used to predict a ∆S = 1 (∆S = 0) B d/s decay rate as a function of γ (using SU (3) symmetry). The measurement of this decay rate then gives γ. We illustrate this technique using different cases. Most of the decay modes we use are expected to be accessible at the B-factories (e + e − or hadron machines).