Critical look at rescattering effects on gamma from B+-> K pi - art. no. 013005

Three ways of dealing with rescattering effects in B+/- --> K-o pi(+/-) are compared, in order to determine the weak phase gamma from these processes and B+/- --> K+/- pi(o). We find that neglecting these contributions altoge ther may involve sizeable errors in gamma, depending on the rescattering am plitude 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+/-Ko) suffers from a large theoretical error due to SU(3) breaki ng, which may be resolved when using also the processes B+/--->pi(+/-)eta(8 ).