Improved limits on the hadronic and semi-hadronic CP violating parameters and role of a dark force carrier in the electric dipole moment of ${}^{199}$Hg

Abstract

Combining the recently reported electric dipole moment (EDM) of ${}^{199}$Hg atom due to breaking of parity and time-reversal symmetries with the improved relativistic atomic calculations, precise limits on the tensor-pseudotensor (T-PT) electron-nucleus (e-N) coupling coefficient and the nuclear Schiff moment (NSM) interactions are determined. Using these limits with the nuclear calculations, we infer limits on the EDMs of neutron and proton as $d_n<2.2\times 10^{-26}|e|\mathrm{cm}$ and $d_p<2.1\times 10^{-25}|e|\mathrm{cm}$, respectively, and on the quantum chromodynamics (QCD) parameter and the combined up- and down- quark chromo-EDMs as $|\bar{\theta }|<1.1\times 10^{-10}$ and $|{\tilde{d}}_u-{\tilde{d}}_d|<5.5\times 10^{-27}|e|\mathrm{cm}$, respectively. These are the best limits till date to probe new sources of CP violation beyond the standard model (SM) from a diamagnetic atom. Role of considering a capable many-body method to account the electron correlation effects to all orders for inferring the above limits has been highlighted. From this analysis, constraints on the T-PT e-N coupling coefficient with a large range of mass of a possible dark matter carrier $\chi$ between the atomic electrons and nucleus are given.

Comments: 2 tables and 4 figures; Accepted for Phys. Rev. D