The proton-antiproton mass threshold structure in psi(3686) radiative decay revisited

Abstract

The near-threshold behavior of the ppbar invariant mass spectrum from the psi(3686) -> gamma ppbar decay reported recently by the BESIII Collaboration is analyzed. The enhancement in the ppbar invariant mass spectrum near threshold is nicely reproduced by the ppbar final-state interaction based on the isospin averaged 1S0 partial-wave amplitude as predicted by the Julich nucleon--antinucleon model. Contributions from the f_2(1910) or f_2(1950) mesons, as promoted in earlier works, are not needed.

3 pages, 3 figures, chi^2 for the results added, to be published in Phys. Rev. D