Skyrmions in models with pions and rho mesons

TL;DR

This paper explores extended Skyrme models with rho mesons, demonstrating that including these mesons significantly reduces Skyrmion binding energies to levels closer to experimental nuclear data while preserving their qualitative features.

Contribution

It introduces a new class of Skyrme models with rho mesons that lower binding energies without altering Skyrmion symmetries, aligning theory more closely with experiments.

Findings

Binding energies reduced to below 4% with rho mesons.

Skyrmion energies can be lowered below standard model values.

Qualitative features and symmetries of Skyrmions are preserved.

Abstract

A problem with the standard Skyrme model is that Skyrmion binding energies are around $15\%$, being much larger than the order $1\%$ binding energies of the nuclei that they aim to describe. Here we consider theories that extend the standard Skyrme model of pions by including rho mesons, via dimensional deconstruction of Yang-Mills theory with an extra dimension. We report the first results of parallel numerical computations of multi-Skyrmions in theories of this type, including a model that reduces Skyrmion energies below those of the standard Skyrme model whilst retaining exactly the same Faddeev-Bogomolny energy bound. We compute all Skyrmions with baryons numbers up to 12 and find that the inclusion of rho mesons reduces binding energies to less than $4\%,$ and therefore moves Skyrmion theory closer to experimental data. Furthermore, we find that this dramatic reduction in binding energies is obtained without changing the qualitative features of the Skyrmions, such as their symmetries.