High Energy Physics

Neutrino physics entered a new era in the last decade. With the discovery of a non-vanishing neutrino rest mass in oscillation experiments a variety of new questions showed up in the context of nuclear and particle physics. One of the crucial questions is the determination of the absolute neutrino mass, which cannot be measured in oscillation experiments. One option is neutrino-less double beta decay, the simultaneous conversion of two neutrons into two protons emitting two electrons. This total lepton number violating process requires that neutrinos are their own antiparticles and is considered to be gold plated. Furthermore, the measured half-life is directly linked with the neutrino mass. Currently, half-life measurements beyond 1025 years are discussed. This requires a large amount of the isotope of interest and a reduction of disturbing background to the smallest possible level. Indeed it is a search for the needle in a haystack. After a general introduction into double beta decay and the related physics, the talk will focus on the status of the experiments GERDA, COBRA and SNO+.

The Large Hadron Collider has been operating for more than a year and delivering exciting results. It has already excluded large parts of the parameter space for supersymmetry. If the hints of a Higgs boson at 125 GeV hold up, the implications for supersymmetry are even more profound. I will explain some of the consequences, including the failure of large classes of models like general gauge mediation to account for such a heavy Higgs. I will also discuss some ideas about how to look for scalar top quarks, which must be present in the low-energy spectrum for supersymmetry to be natural.