Discovery of the shape coexisting 0+ state in 32Mg by a two neutron transfer reaction

TL;DR

This study identifies a coexisting 0+ shape state in 32Mg via a two-neutron transfer reaction, revealing an unexpectedly low excitation energy and long lifetime, challenging existing theoretical models.

Contribution

It reports the first experimental identification of a shape coexistent 0+ state in 32Mg using inverse kinematics transfer reactions, with energy and lifetime measurements that challenge current theories.

Findings

Identified a 0+ shape coexistent state at 1058 keV.

Observed a lifetime exceeding 10 ns for this state.

Found excitation energy lower than theoretical predictions.

Abstract

The Island of Inversion nucleus 32Mg has been studied by a (t,p) two neutron transfer reaction in inverse kinematics at REX-ISOLDE. The shape coexistent excited 0+ state in 32Mg has been identified by the characteristic angular distribution of the protons of the DeltaL = 0 transfer. The excitation energy of 1058 keV is much lower than predicted by any theoretical model. The low gamma-ray intensity observed for the decay of this 0+ state indicates a lifetime of more than 10 ns. Deduced spectroscopic amplitudes are compared with occupation numbers from shell model calculations.