Extracting B(omega ->pi(+) pi(-)) from the timelike pion form factor - art. no. 076002

We extract the G-parity-violating branching ratio B(omega-->pi(+)pi(-)) fro m the effective rho(0)-omega mixing matrix element <(Pi)over tilde>(rho ome ga)(s), determined from e(+)e(-)-->pi(+)pi(-) data. The omega-->pi(+)pi(-) partial width can be determined either from the timelike pion form factor o r through the constraint that the mixed physical propagator D-rho omega(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-->pi(+)pi( -)) = 1.9 +/- 0.3%. [S0556-2821 (99)05005-5].