Electric and magnetic response to the continuum for A=7 isobars in a dicluster model

TL;DR

This paper investigates the magnetic and electric responses of A=7 isobars using a dicluster model, revealing small magnetic contributions and providing calculations relevant for astrophysical processes.

Contribution

It introduces a dicluster model analysis of A=7 isobars, including magnetic response calculations and sum rules, with applications to astrophysical reaction rates.

Findings

Magnetic dipole response is small compared to electric excitations.

Derived a molecular magnetic dipole sum rule matching numerical results.

Calculated astrophysical reaction cross-sections with good experimental agreement.

Abstract

Mirror isobars $^7$Li and $^7$Be are investigated in a dicluster model. The magnetic dipole moments and the magnetic dipole response to the continuum are calculated in this framework. The magnetic contribution is found to be small with respect to electric dipole and quadrupole excitations even at astrophysical energies, at a variance with the case of deuteron. Energy weighted molecular sum rules are evaluated and a formula for the molecular magnetic dipole sum rule is found which matches the numerical calculations. Cross-sections for photo-dissociation and radiative capture as well as the S-factor for reactions of astrophysical significance are calculated with good agreement with known experimental data.