Relativistic approach to the nuclear breathing mode

TL;DR

This paper develops a relativistic microscopic theory incorporating quasiparticle-vibration coupling to accurately describe the isoscalar giant monopole resonance across various nuclei, improving upon mean-field models.

Contribution

It introduces a parameter-free, relativistic approach with beyond-mean-field correlations for better nuclear resonance predictions.

Findings

Successful realistic description of ISGMR in multiple nuclei

Demonstrates the importance of quasiparticle-vibration coupling

Reveals the role of quadrupole states in ISGMR placement

Abstract

Microscopic theory of the nuclear response based on the relativistic meson-nucleon Lagrangian is applied to the description of the isoscalar giant monopole resonance (ISGMR) in a variety of nuclear systems. It is shown that the parameter-free inclusion of beyond-mean-field correlations of the quasiparticle-vibration coupling (qPVC) type in the leading approximation allows for a simultaneous realistic description of the ISGMR in nuclei of lead, tin, zirconium, and nickel mass regions, which is difficult on the mean-field level. The calculations employ the finite-range effective meson-nucleon interaction, which, in combination with the qPVC, has consistently demonstrated the ability to reliably describe many other nuclear structure phenomena. Systematic calculations of the isoscalar monopole response for nickel isotopes help reveal the central role of the coupling between the ISGMR and the low-energy quadrupole states in the placement of the ISGMR centroids.