Uncertainty in the 0νββ decay nuclear matrix elements -: art. no. 044302

The nuclear matrix elements M-0nu of the neutrinoless double-beta decay (0nubetabeta) are evaluated for Ge-76, Mo-100, Te-130, and Xe-136 within the renormalized quasiparticle random phase approximation (RQRPA) and the simple QRPA. Three sets of single particle level schemes are used, ranging in size from 9 to 23 orbits. When the strength of the particle-particle interaction is adjusted so that the 2nubetabeta decay rate is correctly reproduced, the resulting M-0nu values become essentially independent of the size of the basis, and of the form of different realistic nucleon-nucleon potentials. Thus, one of the main reasons for variability of the calculated M-0nu within these methods is eliminated.