Studies of parity and time reversal violations in heavy polar molecules

Summary

Investigation of phenomena involving parity (P) and time reversal (T) symmetry violations is of fundamental importance in physics. A few experiments to search for the P,T-odd effects have been performed on TlF and YbF molecules and considerable progress for PbO and PbF molecules is on the way. For the interpretation of the measured experimental data, it is necessary to calculate a few molecular properties which cannot be measured experimentally. These molecular properties establish some connection between the measured data and well studied fundamental constants. Very accurate and reliable calculations of these properties usually require accurate accounting for both relativistic and correlation effects in heavy-atom systems. In this review, we discuss the P, T-odd interaction constants W _d and W _s. The interaction constant W _d arises from the interaction of electron electric dipole moment (EDM) d _e with the molecular electric field, and the constant W _s arises due to the electron-nucleus scalar-pseudoscalar (S-PS) interaction. The knowledge of W _d is essential to put a reliable limit on the electron EDM d _e , where as the knowledge of W _s is necessary to get the information about the electron-nucleus (S-PS) coupling constant k _s , and to test the Standard Model (SM) of particle physics. Presently available theoretical results of W _d and W _s for the ground states of YbF and BaF molecules are also presented.