Multi-isotope degeneracy of neutrinoless double beta decay mechanisms in the quasi-particle random phase approximation

Understand

We calculate nuclear matrix elements (NME) of neutrinoless double beta decay in four different candidate nuclei (Ge-76, Se-82, Mo-100, Te-130) within the quasiparticle random phase approximation (QRPA) and its uncertainties.

• We assume (up to) four coexisting mechanisms for neutrinoless double beta decay, mediated by light Majorana neutrino exchange, heavy Majorana neutrino exchange, R-parity breaking supersymmetry, and squark-neutrino, interfering either constructively or destructively with each other.
• We find that, unfortunately, current NME uncertainties appear to prevent a robust determination of the relative contribution of each mechanism to the decay amplitude, even assuming accurate measurements of decay lifetimes.
• The near-degeneracy of the decay mechanisms is analyzed with simple algebraic techniques, which do not involve assumptions about the statistical distribution of errors.