Marianne Abstract

Marianna Safronova
University of Delaware

"The search for new physics with atomic systems"

A number of extensions of the standard model of particle physics predict electric dipole moments (EDM) of particles that may be observable with the present state-of-the art experiments making EDM studies a remarkable tool in search for new physics. The EDMs arise from the violations of both parity and time-reversal invariances. The electron EDM is enhanced in certain atomic and molecular systems, and two of the most stringent limits on the electron EDM de were obtained from the experiments with 205Tl and with YbF molecule. These limits significantly constrain supersymmetric and other extensions of the standard model. Both results crucially depend on the calculated values of the effective electric field on the valence electron. In the case of Tl this effective field is proportional to the applied field E0, Eeff=K E0, and d(205Tl)=K de. I will report our recent results that resolve the present controversy in the value of the EDM enhancement factor K in Tl. In the second part of the talk, I will discuss another direction toward the search for new physics with atomic systems, the search for variation of fundamental constants. I will review the present status of relevant laboratory and astrophysical studies, and outline the proposals for future developments of frequency standards needed for the next generation of such tests. Recent advances in theoretical calculations that allowed to reduce the uncertainty of the present best optical frequency standard based on the Al+ ion are discussed.