Pairing phase transition in the odd-A nuclei: identification and classification

TL;DR

This study investigates the pairing phase transition in the odd-A nucleus 161Dy using advanced theoretical methods, revealing it as a first-order transition influenced by pairing strength and challenging traditional indicators like heat capacity curves.

Contribution

It combines covariant density functional theory with shell-model-like approaches to clarify the nature of pairing transitions in 161Dy, highlighting the role of blocking effects and nonlinear pairing strength impacts.

Findings

Pairing transition in 161Dy is first-order around 0.7-1.0 MeV.

Heat capacity curves alone do not definitively indicate pairing transitions.

Varying pairing strength affects transition characteristics nonlinearly.

Abstract

The investigation into the pairing phase transition in the odd-A nucleus 161Dy utilizes a sophisticated blend of covariant density functional theory and the shell-model-like approach. It is discerned that variations in thermodynamic quantities at the critical temperature do not exclusively align with pairing phase transitions. The presence of an S-shaped heat capacity curve, often interpreted as an indication of such transitions, does not offer a definitive confirmation. Additional factors, including the blocking effect, can modify the heat capacity curve and impede the transition process. The pairing phase transition in 161Dy, occurring around 0.7 to 1.0 MeV, is unequivocally characterized as a first-order transition. Furthermore, an exploration into the impact of varying strengths of pairing correlations on these transitions reveals a nonlinear relationship, adding complexity to the transition dynamics.