High-resolution (p,t) reaction measurements as spectroscopic tests of {\it ab-initio} theory in the mid $pf$-shell

TL;DR

This study combines high-resolution (p,t) transfer reaction measurements with advanced ab-initio shell-model calculations to test and benchmark nuclear structure theories in the mid pf-shell, focusing on excited states in $^{50}$Cr and $^{62}$Zn.

Contribution

It provides detailed experimental data and compares it with cutting-edge ab-initio calculations, demonstrating good agreement and advancing nuclear structure modeling.

Findings

Good agreement in level ordering between experiment and theory

Slight over-binding observed in theoretical calculations

Identification of several previously unobserved states

Abstract

Detailed spectroscopic measurements of excited states in $^{50}$Cr and $^{62}$Zn were performed using 24~MeV (p,t) transfer reactions on $^{52}$Cr and $^{64}$Zn, respectively. In total, forty-five states in $^{50}$Cr and sixty-seven states in $^{62}$Zn were observed up to excitation energies of 5.5~MeV, including several previously unobserved states. These experimental results are compared to {\it ab-initio} shell-model calculations using chiral effective field theory ($\chi$-EFT) with the valence-space in-medium similarity renormalization group (VS-IMSRG) method. This comparison demonstrates good agreement in the level orderings with these new theoretical methods, albeit with a slight over binding in the calculations. This work is part of a continued push to benchmark {\it ab-initio} theoretical techniques to nuclear structure data in $0^+\rightarrow0^+$ superallowed Fermi $\beta$ decay systems.