Critical look at rescattering effects on γ from B⁺→Kπ

Three ways of dealing with rescattering effects in B^±→K⁰π^± are compared, in order to determine the weak phase γ from these processes and B^±→K^±π⁰. We find that neglecting these contributions altogether may involve sizeable errors in γ, depending on the rescattering amplitude and on the value of a certain measurable strong phase. We show that an attempt to eliminate these effects by using the charge-averaged rate of B^±→K^±K⁰ suffers from a large theoretical error due to SU(3) breaking, which may be resolved when using also lhe processes B^±→π^±η₈.