Skyrmions with massive pions

TL;DR

This paper demonstrates that in the Skyrme model with massive pions, multi-Skyrmion configurations become unstable and collapse into new stable structures with flat shapes and clustering, aligning better with real nuclear properties.

Contribution

The study reveals that massive pions induce instability in shell-like Skyrmions, leading to the formation of stable, clustered Skyrmions with different geometries, a novel insight into Skyrmion behavior.

Findings

Shell-like Skyrmions are unstable with massive pions.

New stable Skyrmions have flat structures and clustering.

Results align better with real nuclear phenomena.

Abstract

In the Skyrme model with massless pions, the minimal energy multi-Skyrmions are shell-like, with the baryon density localized on the edges of a polyhedron that is approximately spherical and generically of the fullerene-type. In this paper we show that in the Skyrme model with massive pions these configurations are unstable for sufficiently large baryon number. Using numerical simulations of the full nonlinear field theory, we show that these structures collapse to form qualitatively different stable Skyrmion solutions. These new Skyrmions have a flat structure and display a clustering phenomenon into lower charge components, particularly components of baryon numbers three and four. These new qualitative features of Skyrmions with massive pions are encouraging in comparison with the expectations based on real nuclei.