Analysis of the p p-bar mass spectrum from J/psi decay

Abstract

The near-threshold enhancement in the pp̄ invariant mass spectrum of the reaction J/→γpp̄, observed in an experiment by the BES Collaboration, is analysed. It is shown, within the Watson-Migdal approach to final state interactions, that the mass dependence of the pp̄ spectrum close to the threshold can be reproduced by the S-wave pp̄ interaction of the Jülich NN̄ model in the isospin I=1 state. Difficulties in the consistent interpretation of the pp̄ invariant mass spectrum of the reaction J/→π0pp̄, where there are no obvious signs for a final state interaction, are discussed. © 2005 American Institute of Physics.