Shell-model calculation of neutrinoless double- β decay of Ge 76

In this article we present an extension of our recent Rapid Communication [Phys. Rev. C 90, 051301(R) (2014)]PRVCAN0556-281310.1103/PhysRevC.90.051301 where we calculate the nuclear matrix elements for neutrinoless double-β decay of Ge76. For the calculations we use a novel method that has perfect convergence properties and allows one to obtain the nonclosure nuclear matrix elements for Ge76 with a 1% accuracy. We present a new way to calculate the optimal closure energy; using this energy with the closure approximation provides the most accurate closure nuclear matrix elements. In addition, we present a new analysis of the heavy-neutrino-exchange nuclear matrix elements, and we compare occupation probabilities and Gamow-Teller strength with experimental data.