Muon capture rates within the projected QRPA

TL;DR

This paper investigates muon capture rates in light nuclei using QRPA, emphasizing the importance of particle number conservation and the sensitivity to model parameters, with a focus on the robustness of exclusive transition data.

Contribution

It highlights the role of particle number conservation in QRPA calculations and discusses the impact of Coulomb field effects and model sensitivities on muon capture rate predictions.

Findings

Particle number conservation is crucial for accurate muon capture rates.

Coulomb field effects are minor for light nuclei but relevant for heavier nuclei.

Exclusive muon transition data provide more reliable tests of nuclear models.

Abstract

The conservation of the number of particles within the QRPA plays an important role in the evaluation muon capture rates in all light nuclei with A \precsim 30 . The violation of the CVC by the Coulomb field in this mass region is of minor importance, but this effect could be quite relevant for medium and heavy nuclei studied previously. The extreme sensitivity of the muon capture rates on the 'pp' coupling strength in nuclei with large neutron excess when described within the QRPA is pointed out. We reckon that the comparison between theory and data for the inclusive muon capture is not a fully satisfactory test on the nuclear model that is used. The exclusive muon transitions are much more robust for such a purpose.