Coupled-Cluster Calculations of Neutrinoless Double-β Decay in 48Ca

Abstract

We use coupled-cluster theory and nuclear interactions from chiral effective field theory to compute the nuclear matrix element for the neutrinoless double-β decay of 48Ca. Benchmarks with the no-core shell model in several light nuclei inform us about the accuracy of our approach. For 48Ca we find a relatively small matrix element. We also compute the nuclear matrix element for the two-neutrino double-β decay of 48Ca with a quenching factor deduced from two-body currents in recent ab initio calculation of the Ikeda sum rule in 48Ca [Gysbers et al., Nat. Phys. 15, 428 (2019)].