My main interests are in particle astrophysics, mainly in the physics of Neutrinos, Dark Matter, axions and axion-like particles. For many years, I have been active in neutrino less double-beta decay with the experiments: Majorana Demonstrator, and the Cryogenic Underground Observatory for Rare Events, CUORE. Recently, we have been experimenting with zone-refinement of germanium and tellurium dioxide, materials used for ultra-low background detectors for double-beta decay and for searches for exotic particles. My USC group played the leadership role in the purification of the germanium, enriched to 87% in 76Ge, for the Majorana Demonstrator. This resulted in lowering the background, especially in the low-energy region, which resulted in the ability to search for new physics, namely Dark Matter, axions, a violation of the Pauli-exclusion Principle and spontaneous decay of the electron. These results are discussed in several of the articles listed below.
Recently, my colleague Richard Creswick and I are investigating new methods for searching for heavy-sterile-neutrino dark matter, and a new approach to search for axions and axion-like particles. These are exciting new areas that might well play important roles in the future of our Particle Astrophysics Group.