Long-distance final-state interactions andJ/ψdecay

Abstract

To understand the short- versus long-distance final-state interactions, we have performed a detailed amplitude analysis for the two-body decay J/{psi}{r_arrow}1{sup {minus}}0{sup {minus}}. The current data favor a large relative phase nearly 90{degree} between the three-gluon and the one-photon decay amplitudes. The source of the phase is apparently the long-distance final-state interaction. Nothing anomalous is found in the magnitudes of the three-gluon and one-photon decay amplitudes. We discuss the implications of this large phase in the weak decay of heavy particles. {copyright} {ital 1998} {ital The American Physical Society}