ExtractingB(ω→π+π−)from the timelike pion form factor

We extract the {ital G}-parity-violating branching ratio B({omega}{r_arrow}{pi}{sup +}{pi}{sup {minus}}) from the effective {rho}{sup 0}-{omega} mixing matrix element {tilde {Pi}}{sub {rho}{omega}}(s), determined from e{sup +}e{sup {minus}}{r_arrow}{pi}{sup +}{pi}{sup {minus}} data. The {omega}{r_arrow}{pi}{sup +}{pi}{sup {minus}} partial width can be determined either from the timelike pion form factor or through the constraint that the mixed physical propagator D{sub {rho}{omega}}{sup {mu}{nu}}(s) possesses no poles. The two procedures are inequivalent in practice, and we show why the first is preferred, to find finally B({omega}{r_arrow}{pi}{sup +}{pi}{sup {minus}})=1.9{plus_minus}0.3{percent}. {copyright} {ital 1999} {ital The American Physical Society}