The role of P-wave inelasticity in J/psi to pi+pi-pi0

We discuss the importance of inelasticity in the P-wave pi pi amplitude on the Dalitz distribution of 3pi events in J/psi decay. The inelasticity, which becomes sizable for pi pi masses above 1.4 GeV, is attributed to KK to pi pi rescattering. We construct an analytical model for the two-channel scattering amplitude and use it to solve the dispersion relation for the isobar amplitudes that parametrize the J/psi decay. We present comparisons between theoretical predictions for the Dalitz distribution of 3pi events with available experimental data.