Determining the Weak Phase $γ$ in the Presence of Rescattering

We suggest a technique to determine the CKM phase $\gamma$ without neglecting the soft final state rescattering effects. Using a set of 5 $\Delta S = 0$ (or $\Delta S= 1$) $B$ meson (time integrated) decay rates, we compute the strong phases and magnitudes of the tree and penguin contributions as a function of $\gamma$. These are used to predict a $\Delta S = 1$ $(\Delta S = 0)$ decay rate as a function of $\gamma$ (using SU(3) symmetry). The measurement of this decay rate then gives $\gamma$. We illustrate this technique using three cases. All the decay modes we use are expected to be accessible at the $B$-factories ($e^+ e^-$ or hadron machines).