${^3{\rm He}}(\alpha,\gamma){^7{\rm Be}}$ and ${^3{\rm H}}(\alpha,\gamma){^7{\rm Li}}$ astrophysical $S$ factors from the no-core shell model with continuum

TL;DR

This study uses the no-core shell model with continuum to calculate astrophysical S factors for helium and tritium fusion reactions, achieving reasonable agreement with experimental data and providing insights into resonance properties.

Contribution

First application of the no-core shell model with continuum to compute S factors for these fusion reactions using a renormalized chiral interaction.

Findings

S factors for ${^3{ m He}}( ext{α}, ext{γ}){^7{ m Be}}$ agree with experiments

S factors for ${^3{ m H}}( ext{α}, ext{γ}){^7{ m Li}}$ are overestimated

Resonance properties are well reproduced by the model

Abstract

The ${^3{\rm He}}(\alpha,\gamma){^7{\rm Be}}$ and ${^3{\rm H}}(\alpha,\gamma){^7{\rm Li}}$ astrophysical $S$ factors are calculated within the no-core shell model with continuum using a renormalized chiral nucleon-nucleon interaction. The ${^3{\rm He}}(\alpha,\gamma){^7{\rm Be}}$ astrophysical $S$ factors agree reasonably well with the experimental data while the ${^3{\rm H}}(\alpha,\gamma){^7{\rm Li}}$ ones are overestimated. The seven-nucleon bound and resonance states and the $\alpha+{^3{\rm He}}/{^3{\rm H}}$ elastic scattering are also studied and compared with experiment. The low-lying resonance properties are rather well reproduced by our approach. At low energies, the $s$-wave phase shift, which is non-resonant, is overestimated.