Neutrinoless Double-Beta Decay to Excited 0+ States Mediated by Light Majorana Neutrinos

Abstract

The neutrinoless double-beta decay (0νββ decay) to the first excited 0+ collective final state is examined for A = 76, 82, 100 and 136 nuclei by assuming light Majorana neutrino exchange mechanism. Realistic calculations of nuclear matrix elements are performed within the renormalized Quasiparticle Random Phase Approximation. Transitions to the first excited two-quadrupole phonon 0+ state are described within a boson expansion formalism. It is found that the 100Mo is a good candidate for experimental study of the 0νββ decay to excited 0+ state due to small suppression of this transition relative to the transition to the ground state.