Analysis of Enhancement factors of Parity and Time Reversal Violating Effects for Monofluorides

TL;DR

This paper investigates the enhancement factors of parity and time-reversal violating effects in heavy monofluorides, using relativistic calculations to identify promising molecules for probing physics beyond the Standard Model.

Contribution

It provides detailed relativistic coupled cluster calculations of Eeff and Ws for group 12 and 2 monofluorides, highlighting SrF and CdF as new experimental candidates.

Findings

Group 12 monofluorides have large Eeff and Ws values.

Eeff and Ws increase with atomic number Z.

SrF and CdF are proposed as new candidate molecules.

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 work, we analyze the effective electric field (Eeff) that is required for determining the electron electric dipole moment (eEDM), and the scalar-pseudoscalar (S-PS) interaction constant (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 new candidate molecules for experiment.