Enhancement factors of parity- and time-reversal-violating effects for monofluorides

Abstract

Heavy polar diatomic molecules are currently one of the leading candidates for probing physics beyond the standard model via studies of time-reversal (T) and parity (P) violations. In this paper, we analyze the effective electric field (Eeff) that is required for determining the electron electric dipole moment (eEDM), and the scalarpseudoscalar (S-PS) interaction coefficient (Ws), in group-12 and group-2 systems. We use a relativistic coupled cluster method for our calculations, and find that group-12 monofluorides have large Eeff and Ws (for example, the values of Eeff and Ws of CnF, the heaviest group-12 fluoride, are 662 GV/cm and 3360 kHz, respectively). The reason for this is the contraction of the valence s and p orbitals due to the weak screening effect of the outermost core’s d electron. The calculations of Eeff and Ws show that their ratio, Ws/Eeff, increases with Z. Based on these results, as well as experimental suitability, we propose SrF and CdF as candidate molecules for experiment.