Neutrinoless double beta decay

The search for neutrinoless double beta decay is the only practical way to test whether neutrinos are Majorana or Dirac particles. The next generation of experiments aim to probe the effective Majorana neutrino mass down to few 10 meV, as predicted by oscillation experiments in case of the inverse mass hierarchy. According to recent nuclear matrix calculations, the predicted decay rates per mass of double beta isotope are varying within a factor of few when comparing them within the same theoretical model framework. The sensitivity of the upcoming experiments depend therefore primarily on the available mass of double beta isotopes and the experimental conditions. In particular, the achievable background suppression and the detection efficiency will be decisive for their success.