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

TL;DR

This paper reanalyzes the near-threshold proton-antiproton mass spectrum in psi(3686) radiative decay, demonstrating that final-state interactions explain the observed enhancement without requiring meson contributions.

Contribution

It shows that the ppbar threshold enhancement can be explained by final-state interactions using the Julich nucleon-antinucleon model, challenging previous meson-based explanations.

Findings

The ppbar invariant mass spectrum near threshold is well reproduced by the final-state interaction model.

No additional contributions from f_2(1910) or f_2(1950) mesons are necessary.

The analysis supports the nucleon-antinucleon interaction as the primary cause of the observed enhancement.

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.