Revisiting the proton-antiproton scattering using a constituent-quark-model based coupled-channels calculation

TL;DR

This paper uses a constituent-quark-model based coupled-channels approach to analyze proton-antiproton scattering, exploring the potential existence of bound states or near-threshold structures related to recent baryonium resonance studies.

Contribution

It introduces a novel coupled-channels calculation with a complex potential derived from a quark model, incorporating annihilation effects constrained by nucleon-nucleon data.

Findings

Nucleon-antinucleon dynamics are complex with scattering singularities near thresholds.

The model suggests possible near-threshold structures or bound states.

The approach provides insights into baryonium resonance phenomena.

Abstract

Motivated by the last experimental and theoretical advances in the analysis of possible baryonium resonances, the $X(1835)$ and their partners, we perform a constituent-quark-model based coupled-channels calculation of the proton-antiproton scattering in order to analyze the possible existence of bound states or near-threshold structures. The used $N\overline N$ potential is derived from a $G$-parity transformation of the quark-model-based $NN$ interaction which has described well deuteron properties, $NN$ phase shifts, and even hadron-hadron phenomenology. The additional $N\overline N$ annihilation is taken into account by a complex phenomenological potential whose real part is generated by one-pion and one-gluon exchange annihilation potentials and its imaginary part is an energy-independent potential of Gaussian form. Then, all the parameters of the interaction are constrained by the $NN$ sector except those determining the imaginary part of the annihilation potential. Our study concludes that the nucleon-antinucleon dynamics is complex and rich in scattering singularities near the proton-antiproton and neutron-antineutron thresholds.