Neutrino physics without neutrinos: Probing fundamental symmetries of nature with neutrino-less double beta decay

Neutrino physics without neutrinos: Probing fundamental symmetries of nature with neutrino-less double beta decay
Andrea Pocar, Department of Physics, UMass Amherst
Andrea Pocar
Date and time: Wed, Jan 23, 2019 - 4:00pm
Refreshments at 3:45pm
Location: Hasbrouck 134
Category: Departmental Colloquium
Abstract:

The search for neutrino-less double beta decay (DBD), an ultra-rare 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 to neutrino-less DBD well beyond the current years half-life lower bound. One of these experiments, nEXO, uses 5 tonnes of liquid xenon highly enriched in the mass-136 isotope and has a design of 10^28 years, two orders of magnitude above current experiments. The nEXO detector combines well-established time projection chamber (TPC) technology, proven by its smaller EXO-200 predecessor, with state-of-the-art innovations and novel engineering solutions required to suppress radioactive backgrounds and make this large-scale facility possible.

This talk introduces the physics of neutrino-less DBD in the context of the “big questions” in particle physics and cosmology, and reviews its experimental challenges. Results from the EXO-200 experiment and the status of the nEXO R&D, some of which happening at UMass are presented.