Ab initio calculations of nuclear charge radii across and beyond ${}^{132}$Sn: Putting chiral EFT nuclear interactions to the test

TL;DR

This study uses ab initio calculations to test chiral EFT nuclear interactions by examining charge radii across the Tin isotopic chain, highlighting their current limitations and future needs for more precise modeling.

Contribution

It demonstrates the sensitivity of nuclear charge radii predictions to the choice of chiral EFT interactions and emphasizes the need for improved models and measurements beyond ${}^{132}$Sn.

Findings

Reproduction of absolute charge radii achieved

Isotopic shift behavior and kink at ${}^{132}$Sn challenge current models

Results are highly sensitive to the Hamiltonian used beyond ${}^{132}$Sn

Abstract

Charge radii are investigated along the Tin isotopic chain via ab initio Bogoliubov coupled cluster calculations at the singles and doubles level. In addition to the reproduction of absolute radii, the parabolic behavior of isotopic shifts between the N = 50 and N = 82 magic numbers and the kink through ${}^{132}$Sn are shown to provide stringent tests for state-of-the-art chiral effective field theory ($\chi$EFT) inter-nucleon interactions. Indeed, none of the employed fine-tuned interactions can capture all such key characteristics. Eventually, the pronounced sensitivity of the results to the employed Hamiltonian beyond ${}^{132}$Sn provides a unique playground to pin down critical attributes of $\chi$EFT inter-nucleon interactions in the future. This calls for measuring isotopic shifts both towards ${}^{100}$Sn and beyond ${}^{134}$Sn, as well as for performing high-accuracy ab initio calculations of mean-square radii in heavy open-shell nuclei by adding both triples corrections to the many-body wave function and the two-body charge density correction to the operator