Isoscalar monopole and quadrupole modes in Mo isotopes: Microscopic analysis

Gianluca Colò,Danilo Gambacurta,Wolfgang Kleinig,Jan Kvasil,Valentin O Nesterenko,Alessandro Pastore

doi:10.1016/j.physletb.2020.135940

Abstract

The recent RCNP (α,α′) data on the Isoscalar Giant Monopole Resonance (ISGMR) and Isoscalar Giant Quadrupole Resonance (ISGQR) in 92,94,96,98,100Mo are analyzed within a fully self-consistent Quasiparticle Random Phase Approximation (QRPA) approach with Skyrme interactions, in which pairing correlations and possible axial deformations are taken into account. The Skyrme sets SkM*, SLy6, SVbas and SkPδ, that explore a diversity of nuclear matter properties, are used. We discuss the connection between the line shape of the monopole strength ISGMR and the deformation-induced coupling between the ISGMR and the K=0 branch of the ISGQR. The ISGMR is best described by the force SkPδ, having a low incompressibility K∞=202MeV. The ISGQR data are better reproduced by SVbas, that has large isoscalar effective mass m⁎/m=0.9. The need of a functional that can describe simultaneously the ISGMR and ISGQR data is stressed, with the requirement of suitable values of K∞ and m⁎/m. Possible extensions of the QRPA to deal with soft systems are also envisaged.

Highlights

There is still a high theoretical and experimental interest in the determination of the parameters of the Equation of State (EoS) of nuclear matter (NM) [1]
It can be linked to compressional modes of finite nuclei, in particular to the isoscalar giant monopole resonance (ISGMR), a breathing mode characterised by a strong transition amplitude from the groundstate [5, 6]
Each potential energy curves (PECs) point is obtained by minimization of the total ground-state energy under the constraint of a fixed

Summary

Introduction

There is still a high theoretical and experimental interest in the determination of the parameters of the Equation of State (EoS) of nuclear matter (NM) [1]. Among these parameters, the nuclear incompressibility ∞ and the isoscalar effective mass ∗∕ constitute crucial benchmarks for testing new models and provide an indispensable guideline for applications of nuclear theory to heavy-ion collisions [2], astrophysical processes [3, 4], and other areas. Being related to the second derivative of the EoS around this minimum, ∞ measures the stiffness of SNM with respect to the compression. The discussion on how to extract ∞ from the ISGMR dates back to the years 1980s [5]

Objectives

Results

Conclusion