Towards tonne-scale Neutrinoless Double Beta Decay Experiments

The search for neutrino-less double beta decay (DBD), a nuclear disintegration allowed only if neutrinos are massive Majorana particles, is entering a new phase. This decay, which has so-far eluded detection, explicitly violates total lepton number conservation by two units, offers a mechanism for the creation of matter over anti-matter, and provides a portal to unraveling the nature of neutrino mass.

A new generation of experiments is being designed to push the detection sensitivity of neutrino-less DBD well beyond what currently available. These novel detectors use one or more tonnes of DBD-decaying isotope to reach half-life sensitivities on the order of 10^28 years, two orders of magnitude better thancurrent experiments.

They combine well-established detector technologies, incremental design improvements, and innovations detector solutions to identify, measure, and suppress radioactive backgrounds with unprecedented efficiency thus fully exploiting the large capital and time investment of these large apparata.

This talk gives an overview of current DBD searches, illustrates the science reach and status of ongoing R&D for tonne-scale experiments and sets the stage for contributed talks presented at the workshop.