Gamow-Teller response in the configuration space of DFT-rooted no-core configuration-interaction model

TL;DR

This paper introduces a novel no-core configuration-interaction model based on multi-reference density functional theory to accurately calculate Gamow-Teller responses across various nuclei, addressing fundamental questions in nuclear physics and astrophysics.

Contribution

The paper presents a new DFT-rooted no-core configuration-interaction approach that effectively captures Gamow-Teller responses in nuclei of different sizes and structures, with broad applicability.

Findings

Successfully computes GT strength distributions in selected nuclei.

Captures GT response with small configuration spaces while satisfying sum rules.

Demonstrates flexibility by applying to superallowed beta decay and low-spin spectra.

Abstract

The atomic nucleus is a unique laboratory to study fundamental aspects of the electroweak interaction. This includes a question concerning in medium renormalization of the axial-vector current, which still lacks satisfactory explanation. Study of spin-isospin or Gamow-Teller (GT) response may provide valuable information on both the quenching of the axial-vector coupling constant as well as on nuclear structure and nuclear astrophysics. We have performed a seminal calculation of the GT response by using the no-core-configuration-interaction approach rooted on multi-reference density functional theory (DFT-NCCI). The model treats properly isospin and rotational symmetries and can be applied to calculate both the nuclear spectra and transition rates in atomic nuclei, irrespectively of their mass and particle-number parity. The method is applied to compute the GT strength distribution in selected $N\approx Z$ nuclei including the $p$-shell $^8$Li and $^8$Be nuclei and the $sd$-shell well-deformed nucleus $^{24}$Mg. In order to demonstrate a flexibility of the approach we present also a calculation of the superallowed GT beta decay in doubly-magic spherical $^{100}$Sn and the low-spin spectrum in $^{100}$In. It is demonstrated that the DFT-NCCI model is capable to capture the GT response satisfactorily well by using relatively small configuration space exhausting simultaneously the GT sum rule. The model, due to its flexibility and broad range of applicability, may either serve as a complement or even as an alternative to other theoretical approaches including the conventional nuclear shell model.