Nuclear structure investigations in the A ≈ 30 mass region

¹ Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, BG-1784, Sofia, Bulgaria
² INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro, Italy
³ Dipartimento di Matematica e Fisica, Università degli Studi della Campania “Luigi Vanvitelli”, I-8110 Caserta, Italy
⁴ INFN, Sezione di Napoli, I-80126 Napoli, Italy
⁵ CSNSM, CNRS/Université, Paris-Sud XI, 91405 Orsay Campus, France

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 21 November 2025

Abstract

Experimental results for the structure of nuclei in the mass region A ≈ 30 are presented. The first part of the paper is dedicated to the mirror nuclei ³¹S and ³¹P. In the second part we focus on the structure of the N=Z nucleus of ³⁰P. Excited states in the ³⁰P, ³¹P and ³¹S were populated in the same experiment as the 1pn, 1p and 1n exit channels of the reaction ²⁰Ne + ¹²C, respectively. The ²⁰Ne beam accelerated to an energy of 33 MeV was delivered by the Piave-Alpi accelerator of the Laboratori Nazionali di Legnaro. Results for branching ratios measurements, angular correlations analysis of coincident γ-rays as well as Doppler-shift attenuation lifetime measurements are reported. The γ-rays were detected using the multi-detector array GASP with the EUCLIDES charged particle detector. The isospin symmetry in A=31 mirror nuclei was investigated using the Equation of Motion method based on a chiral potential and including two- and three-body forces. The level scheme and branching ratios for the positive parity band in the N=Z nucleus of ³⁰P are well reproduced by the shell model calculations.