Dark forces and atomic electric dipole moments

Abstract

Postulating the existence of a finite-mass mediator of T,P-odd coupling between atomic electrons and nucleons we consider its effect on permanent electric dipole moment (EDM) of diamagnetic atoms. We present both numerical and analytical analysis for such mediator-induced EDMs and compare it with EDM results for the conventional contact interaction. Based on this analysis we derive limits on coupling strengths and carrier masses from experimental limits on EDM of 199 Hg atom.

Improved limits on the hadronic and semihadronicCPviolating parameters and role of a dark force carrier in the electric dipole moment ofHg199

“…However, we present them again here to highlight the reasons for which differences between the RPA and CCSD results occur. This could justify the intention for calculating the C χ T coupling coefficients due to the exchange of dark matter candidate χ using the CCSD method, which were determined earlier by the RPA method [36]. It is worth mentioning here that our DHF and RPA results given in the above table agree well with another calculation reported in Ref.…”

“…in fm-3 Distance, r in fm For m χ =∞ For m χ =1000 MeV/c2 For m χ =100 MeV/c 2 For m χ =50 MeV/c (Color online) Behavior of ρ χ N values with the distance from the origin of the nucleus of 199 Hg in the uniform charge distribution for different values of mχ (in MeV/c 2 . This is perfectly in agreement with the findings of Ref [36]…”

“…with ρ 0 = 3Z 4πR 3 for the radius of the sphere R within which the nucleons are uniformly distributed and Θ is the Heaviside step function. Using this approximation, it yields [36] where λχ = /(mχc). As can be seen this density functional goes as ρ χ N (r) ∝ e −r/λχ r .…”

“…It is again strenuous to observe these effects through the accelerator based methods, even though their masses can be of reasonable size, because of their exceptionally smaller cross-sections. In a recent work [36], the P,T-odd interaction between the electrons and nucleons in 199 Hg due to the exchange of a massive light gauge boson χ was investigated and constraint on the T-PT e-N coupling constant with a range of mass of χ (m χ ) was given. In that study, the previously measured experimental data on 199 Hg EDM from Ref.…”

Electric Dipole Moments From Dark Sectors

“…It would be interesting to explore deviations from the contact limit in this lower mass regime (see e.g. [24]). However, once the relevant mass scale becomes too small, (100 keV and smaller), typically, very strong astrophysical bounds on portal couplings can be imposed, leaving little scope for interesting sensitivity via EDM observables.…”