Abstract :
It has recently been pointed out that the observables of the decay B+→K+K0 and its charge conjugate allow us to take into account rescattering effects in constraints on the CKM angle γ arising from B±→π±K and Bd→π±K± modes, and that they play an important role to obtain insights into final-state interactions. In this paper, the formalism needed to accomplish this task is discussed in detail. Furthermore, using a transparent model to describe the rescattering processes, as well as electroweak penguins, we calculate the quantities parametrizing the B+→π+K0 and Bd0→π−K+ decay amplitudes for specific examples, and illustrate the constraints on γ arising from the corresponding observables. Although this model is very crude, it shows nicely the power of B±→K±K both to include the rescattering effects in the bounds on γ and to obtain insights into final-state interactions. Moreover this model exhibits the interesting feature that the combined branching ratio BR(B±→K±K) may be considerably enhanced through rescattering processes, as was recently pointed out within a general framework.
