Two-particle transfer processes as a signature of shape phase transition in Zirconium isotopes

TL;DR

This paper investigates two-particle transfer reactions in Zirconium isotopes as a method to identify shape phase transitions and shape coexistence phenomena, revealing clear signatures of such transitions through detailed calculations.

Contribution

It introduces a novel approach using two-particle transfer reactions and Monte Carlo Shell Model calculations to detect shape phase transitions in Zirconium isotopes.

Findings

Signature of shape phase transition between $^{98}$Zr and $^{100}$Zr.

Coexistence of deformed and spherical $0^+$ states in Zirconium isotopes.

Qualitative differences in transfer reactions distinguish normal from shape phase transitions.

Abstract

We explore two-particle transfer reactions as a unique probe of the occurence of shape coexistence in shape phase transitions. The (t,p) reactions to the ground state and to excited $0^+$ states are calculated for the isotope chain of even-even Zirconium isotopes starting from stable nuclei up to beyond current experimental limits. Two-particle spectroscopic factors derived from Monte Carlo Shell Model calculations are used, together with the sequential description of the two-particle transfer reaction mechanism. The calculation shows a clear signature for a shape phase transition between $^{98}$Zr and $^{100}$Zr, which displays coexistence of a deformed ground state with an excited spherical $0^+$ state. Furthermore, we show that there is a qualitative difference with respect to the case of a normal shape phase transition that can be discriminated with two-neutron transfer reactions.