Particle Physics

Direct dark matter (DM) detection experiments almost always focus on Weakly Interacting Massive Particles (WIMPs), which have a mass in the 1--1000 GeV range.  However, what if DM is not a WIMP?  In this talk, new direct detection strategies for DM particles with MeV to GeV mass will be presented.  In this largely unexplored mass range, DM can scatter with electrons, causing ionization of atoms in a detector target material and leading to single- or few-electron events.  I will present the first direct detection limits on DM as light as a few MeV, using XENON10 data.  Theoretically interesting models can already be probed.  Significant improvements in sensitivity should be possible with dedicated experiments, opening up a window to new regions in DM parameter space.  

During the last ten years, a lot of experimental information has been collected from neutrino oscillation experiments  on the masses and and mixings among the three known  neutrino species. This presents  an almost comparable flavor picture for leptons as is already known to exist for quarks. In the talk I would like to discuss what these results imply for physics beyond the standard model since SM predicts zero neutrino mass. In particular, it seems that one can make a compelling case for the idea of grand unified theory of matter and forces as a candidate theory for neutrinos as well as providing a possible route to flavor unification. I will  outline these arguments,  present a candidate theory and discuss  its tests.