Comparison of $\bar{\hbox{N}}\hbox{N}$ optical models

TL;DR

This paper compares different models of antinucleon-nucleon interactions, highlighting significant discrepancies especially at higher energies and in certain partial waves, and discusses the challenges in interpreting resonant behaviors.

Contribution

It provides a detailed comparison between the Nijmegen partial wave analysis and popular optical potentials, revealing inconsistencies and offering insights into their limitations.

Findings

Severe discrepancies in most partial waves, especially above 400 MeV/c.

Resonant-like structures in specific waves that are hard to interpret as dynamical resonances.

Large deviations between models at short and medium-range distances.

Abstract

We compare the strong part of the $\bar{\hbox{N}}\hbox{N}$ interaction obtained by the Nijmegen partial wave analysis and the results of some of the most popular $\bar{\hbox{N}}\hbox{N}$ optical potentials in configuration space. We have found severe discrepancies in most of the partial waves, especially above $p_{Lab}$=400 MeV/c where the partial wave analysis displays a resonant-like structure in the $^{31}$S$_0$ and $^{33}$P$_0$ waves. Some theoretical difficulties to interpret this behaviour in terms of dynamical resonances are pointed pout and an alternative explanation is suggested. A much better stability is observed in the low energy parameters, apart from some discrepancies due to the presence of near-threshold quasi-bound states in particular waves. Large deviations have also been found between the corresponding potentials, at short and medium-range ($r\gtrsim 1$ fm) distances.