Role of residual interaction in the relativistic description of M1 excitation

TL;DR

This paper investigates how residual interactions influence magnetic dipole (M1) excitations in nuclei using relativistic energy-density functional models, highlighting the role of specific residual interactions and pairing correlations.

Contribution

It introduces a novel relativistic framework to analyze residual interactions' effects on M1 excitations, emphasizing the isovector-pseudovector interaction and pairing correlations.

Findings

The isovector-pseudovector residual interaction significantly affects M1 excitations.

Pairing correlations influence M1 modes in open-shell nuclei.

Experimental data can help refine theoretical models of residual interactions.

Abstract

Magnetic dipole (M1) excitation is the leading mode of multi-nucleon excitations induced by the magnetic field, and is a phenomenon of the spin-orbit (SO) splitting and residual interactions involved. In this work, we investigate the effects of the residual interactions on the M1 excitation from a novel perspective, the framework of relativistic nuclear energy-density functional (RNEDF). The relativistic Hartree-Bogoliubov (RHB) model is utilized to determine the nuclear ground state properties, while the relativistic quasi-particle random-phase approximation (RQRPA) is employed for the description of M1-excitation properties. From the analysis of M1 mode in the Ca isotope chain, role of the isovector-pseudovector (IV-PV) residual interaction is discussed. For open-shell nuclei, the pairing correlation also plays a noticeable role in the M1 mode. The experimental data on M1 mode is expected to provide a suitable reference to improve and optimize the theoretical aspects to describe the residual interactions.