Nuclear Structure 2026

Abrupt structural transition in exotic molybdenum isotopes unveils an isospin-symmetric island of inversion

Jul 28, 2026, 2:30 p.m.

20m

Fletcher Challenge Canada (Simon Fraser University Harbour Centre)

Contributed Talks Tuesday Afternoon Early Session Block

Speaker

Francesco Recchia (University of Padova and INFN)

Description

Protons and neutrons in nuclei are arranged in orbitals that follow a shell structure, with energy gaps at specific magic numbers. Experiments using radioactive beams have shown that these magic numbers vanish in some neutron-rich isotopes. This results in unusual arrangements, where configurations with nucleons scattered to higher energy orbitals are the most bound, forming what has been called "Islands of Inversion".
We have measured the lifetimes of 2+ states in 84Mo and 86Mo isotopes, discovering a dramatic structural change. This has been understood as the boundary of a "Isospin-Symmetric Island of Inversion" [1], where both proton and neutron excitations play an equal role and evolution of collectivity is governed by three-nucleon forces.

[1] J. Ha, F. Recchia et al. Abrupt structural transition in exotic molybdenum isotopes unveils an isospin-symmetric island of inversion. Nat Commun 16, 10631 (2025).
https://doi.org/10.1038/s41467-025-65621-2