CWRU Physics Faculty
Professor of Physics
My interests lie at the intersection of particle physics, astrophysics and cosmology.
Some 30% universe is in the form of a dark matter fundamentally different from ordinary matter. Weakly Interacting Massive Particles, or WIMPs, created in the big bang, are one of the most promising ideas for what this dark matter could be. Particle physics provides a well-motivated possibility for the identity of the WIMP - the lightest, and by necessity stable, particle in supersymmetry.
If there are WIMPs, we should be able to detect their presence in the Milky Way with detectors here on Earth. The challenge is that radioactive backgrounds mask the low event rates expected. I was one of the developers of the sophisticated cryogenic detectors that reject radioactive background and used by the two leading WIMP search experiments - CDMS, and EDLEWEISS. These experiments are now beginning to probe the likely parameter space of WIMP models with detectors with a mass of several kg.
However there is considerable uncertainty in the interaction rate of WIMPs on Earth, and detectors with a mass of at least 1-10 tons are needed to fully test the WIMP hypothesis. My current effort is with the new XENON experiment. This collaboration is developing an exciting new liquid xenon dual-phase time projection chamber technology that promises to rival the CDMS detectors in sensitivity, and is scalable to the multi-ton scale.
I am also a member of the Borexino solar neutrino experiment will make the first direct measurement of the low energy portion of the solar neutrino spectrum. This will provide a very sensitive probe of neutrino oscillations, as well as an important test of our understanding of the rich neutrino physics from the brightest source of neutrinos available to us. Final construction of the experiment is now underway.