Neutrinoless double-beta decay and seesaw mechanism

From the standard seesaw mechanism of neutrino-mass generation, which is based on the assumption that the lepton number is violated at a large (∼1015 GeV) scale, it follows that the neutrinoless double-beta decay (0νββ-decay) is ruled by the Majorana neutrino-mass mechanism. With this notion, we derive for the inverted neutrino-mass hierarchy the allowed ranges of the half-lives of the 0νββ-decay for nuclei of experimental interest with different sets of nuclear matrix elements. The present-day results of the calculation of the 0νββ-decay nuclear matrix elements are briefly discussed. We argue that if 0νββ-decay will be observed in future experiments sensitive to the effective Majorana mass in the inverted mass hierarchy region, then a comparison of the derived ranges with measured half-lives will allow us to probe the standard seesaw mechanism assuming that future cosmological data will establish the sum of the neutrino masses to be about 0.2 eV.