2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/196135In the Skyrme model, atomic nuclei are identified with solitonic configurations. If the pion mass is set to zero, these configurations are spherical shells of energy with a fullerene-like appearance and are well approximated by a simple rational map ansatz. Using simulated annealing, we have calculated minimum energy configurations for non-zero pion mass and have found that they are less round and are less well approximated by the rational map ansatz.6 pages, 3 figures; new data added, clarifications and typo corrections made; version to appear in Europhysics LettersHigh Energy Physics - Theorytext