Phase transitions in N = 40, 60 and 90 nuclei

TL;DR

This study investigates first-order phase transitions in specific nuclei regions using microscopic Skyrme-Hartree-Fock + BCS calculations and compares results with experimental data to identify critical point candidates.

Contribution

It introduces new microscopic position and occupation indices for identifying critical point nuclei in phase transition regions.

Findings

Microscopic calculations confirm expected phase transition behavior.

New indices effectively identify candidate nuclei for critical points.

Comparison with experimental data supports the theoretical predictions.

Abstract

In this paper we focus on three mass regions where first-order phase transitions occur, namely for $N=40$, 60 and 90. We investigate four isotopic chains (Se, Zr, Mo and Nd) in the framework of microscopic Skyrme-Hartree-Fock + Bardeen-Cooper-Schrieffer calculations for 15 different parametrizations. The microscopic calculations show the typical behavior expected for first-order phase transitions. To find the best candidate for the critical point phase transition we propose new microscopic position and occupation indices calculated for positive-parity and negative-parity proton and neutron single-quasiparticle states around the Fermi level. The microscopic calculations are completed by macroscopic calculations within the Algebraic Collective Model (ACM), and compared to the experimental data for $^{74}$Se, $^{102}$Mo and $^{150}$Nd, considered to be the best candidates for the critical point nuclei.