Charge radii of Ca isotopes and correlations

TL;DR

This study investigates how short- and long-range correlations influence the charge radii of calcium isotopes, finding that long-range correlations significantly improve model accuracy compared to experimental data.

Contribution

It introduces a combined approach using Hartree-Fock, BCS, and RPA phonons to analyze correlation effects on nuclear charge radii, highlighting the importance of long-range correlations.

Findings

Long-range correlations significantly modify charge radii predictions.

Short-range correlations have negligible effects.

Model results align better with experimental data when long-range correlations are included.

Abstract

We study the effects of short- and long-range correlations on the charge radii of Ca isotopes. We start our investigation with an independent particle model consisting in Hartree-Fock plus Bardeen-Cooper-Schrieffer calculations with finite-range effective nucleon-nucleon interactions of Gogny type. The short-range correlations effects are evaluated by considering all the terms of a cluster expansion containing a single correlation line. The long-range correlations are taken into account by including the coupling with the quasi-particle random phase approximation phonons. While the effects of the short-range correlations are negligible, those of the long-range correlations largely modify the independent particle model results and improve the agreement with the experimental data.