Antoine Weis
Department of Physics, University of Fribourg, Switzerland
Date
12 December 2007
Title
Elementary Particles in the Mirror of Space and Time: Violation of Discrete Symmetries
Abstract
The role of symmetries in physics will be introduced with special emphasis on two particular discrete symmetries, viz., the parity operation, P, which inverts spatial coordinates and the time reversal operation, T, which reverses the arrow of time. Specific examples of parity violation in the macroscopic world of living matter as well as at the atomic / subatomic scale will be discussed with speculations on possible connections between the two phenomena. In the second part, experiments searching for a permanent electric dipole moment (EDM) of the neutron will be discussed. The coexistence of magnetic and electric dipole moments in an elementary particle violates both the P and T symmetries. The hunt for a finite EDM of an elementary particle has a 50 year long history and experiments have achieved spectacular sensitivities. Since EDM values predicted by the Standard Model (SM) are far beyond the reach of modern experiments, the observation of an EDM is a signature of physics beyond the SM.