Neutrinoless double beta decay is a direct probe of physics beyond the standard model. Its observation would unambiguously demonstrate that the lepton number is not a symmetry of nature and would provide unique informations on the nature and mass of the neutrinos.
Many experiments are searching for this extremely rare decay in a number of candidate isotopes and the most recent results are reviewed. The technological advances and the compelling requirements for the new generation of experiments are discussed.
giulia.pagliaroli@gssi.it