Effects of three-nucleon forces and two-body currents on Gamow-Teller strengths

TL;DR

This paper investigates how three-nucleon forces and two-body currents influence Gamow-Teller transition strengths in certain nuclei, using chiral interactions and advanced computational methods to improve understanding of nuclear beta decay processes.

Contribution

It introduces a consistent approach combining chiral interactions and two-body currents to accurately compute Gamow-Teller strengths and nuclear spectra, highlighting the impact of three-nucleon forces and currents.

Findings

Two-body currents reduce the Ikeda sum rule, indicating quenching of the axial-vector coupling.

The half-life of carbon-14 is sensitive to three-nucleon forces and two-body currents.

Predicted spectra of nitrogen-14, fluorine-22, and fluorine-24 show several new features.

Abstract

We optimize chiral interactions at next-to-next-to leading order to observables in two- and three-nucleon systems, and compute Gamow-Teller transitions in carbon-14, oxygen-22 and oxygen-24 using consistent two-body currents. We compute spectra of the daughter nuclei nitrogen-14, fluorine-22 and fluorine-24 via an isospin-breaking coupled-cluster technique, with several predictions. The two-body currents reduce the Ikeda sum rule, corresponding to a quenching factor q^2 ~ 0.84-0.92 of the axial-vector coupling. The half life of carbon-14 depends on the energy of the first excited 1+ state, the three-nucleon force, and the two-body current.