Nuclear matrix element of $2\nu \beta \beta$ decay of ${}^{76}$Ge: roles of high-lying states and two-body currents

Hua-Yang Xu, Hao Zhou, Long-Jun Wang

We present a microscopic analysis of the nuclear matrix element (NME) of the two-neutrino double-$\beta$ ($2\nu \beta \beta$) decay for open-shell heavy deformed nuclei, taking into account the fa…