In-beam gamma-ray spectroscopy of 35Mg and 33Na

TL;DR

This study reports the first gamma-ray spectroscopy of neutron-rich nuclei 35Mg and 33Na, revealing new transitions and providing insights into their nuclear structure and shell-model predictions.

Contribution

First observation of gamma-ray transitions in 35Mg and 33Na, expanding understanding of their excited states and shell-model configurations.

Findings

Gamma-ray transition observed in 35Mg for the first time.

New gamma-ray transition identified in 33Na.

Results support shell-model predictions of intruder states and rotational bands.

Abstract

Excited states in the very neutron-rich nuclei 35Mg and 33Na were populated in the fragmentation of a 38Si projectile beam on a Be target at 83 MeV/u beam energy. We report on the first observation of gamma-ray transitions in 35Mg, the odd-N neighbor of 34Mg and 36Mg, which are known to be part of the "Island of Inversion" around N = 20. The results are discussed in the framework of large- scale shell-model calculations. For the A = 3Z nucleus 33Na, a new gamma-ray transition was observed that is suggested to complete the gamma-ray cascade 7/2+ --> 5/2+ --> 3/2+ gs connecting three neutron 2p-2h intruder states that are predicted to form a close-to-ideal K = 3/2 rotational band in the strong-coupling limit.