Charge-exchange transitions from the ab initio symmetry-adapted no-core shell model *

The symmetry-adapted no-core shell model (SA-NCSM) utilizes emergent symmetries in nuclei in order to reduce the dimensionality of the model space. This, in turn, allows one to reproduce the low-energy nuclear dynamics with only a small fraction of the model space, and hence making solutions to heavier nuclei and ultralarge model spaces feasible. The symmetry-adapted basis of the SA-NCSM is well suited for describing electromagnetic and beta-decay transitions enabling us to perform calculations for up to pf-shell nuclei. This work discusses calculations of recoil-order corrections in analyses of beta decay experiments for ⁸Be that probe fundamental symmetries as well as calculations of neutrinoless double beta decay matrix elements necessary to study whether neutrinos are their own antiparticles.