Electric dipole polarizability of $^{58}$Ni

TL;DR

This study measures the electric dipole polarizability of $^{58}$Ni using proton scattering experiments and compares results with theoretical models, providing insights into nuclear structure and testing advanced computational methods.

Contribution

It provides the first experimental determination of $^{58}$Ni's electric dipole polarizability and compares it with state-of-the-art theoretical calculations, validating recent nuclear models.

Findings

Experimental polarizability: 3.48(31) fm$^3$

Good agreement with quasiparticle RPA calculations including vibration coupling

Supports extensions of coupled-cluster calculations with chiral EFT for nuclei

Abstract

The electric dipole strength distribution in $^{58}$Ni between 6 and 20 MeV has been determined from proton inelastic scattering experiments at very forward angles at RCNP, Osaka. The experimental data are rather well reproduced by quasiparticle random-phase approximation calculations including vibration coupling, despite a mild dependence on the adopted Skyrme interaction. They allow an estimate of the experimentally inaccessible high-energy contribution above 20 MeV, leading to an electric dipole polarizability $\alpha_\mathrm{D}(^{58}{\rm Ni}) = 3.48(31)$ fm$^3$. This serves as a test case for recent extensions of coupled-cluster calculations with chiral effective field theory interactions to nuclei with two nucleons on top of a closed-shell system.