Quark Loop Contributions to Neutron, Deuteron, and Mercury EDMs from Supersymmetry without R parity

TL;DR

This paper analyzes how supersymmetry without R parity can generate large electric dipole moments in neutrons, deuterons, and mercury, providing new bounds on RPV parameters from current and future experiments.

Contribution

It offers explicit analytical expressions for quark-scalar loop contributions and establishes robust bounds on R-parity violating parameters, especially from neutron and deuteron EDMs.

Findings

Neutron and deuteron EDMs are significantly larger than mercury EDM.

Future EDM experiments can impose strong constraints on RPV parameters.

Even with high slepton masses, EDM contributions remain detectable.

Abstract

We present a detailed analysis of the neutron, deuteron and mercury electric dipole moment from supersymmetry without R parity, focusing on the quark-scalar loop contributions. Being proportional to top Yukawa and top mass, such contributions are often large. Analytical expressions illustrating the explicit role of the R-parity violating parameters are given following perturbative diagonalization of mass-squared matrices for the scalars. Dominant contributions come from the combinations $B_i \lambda^{\prime}_{ij1}$ for which we obtain robust bounds. It turns out that neutron and deuteron EDMs receive much stronger contributions than mercury EDM and any null result at the future deuteron EDM experiment or Los Alamos neutron EDM experiment can lead to extra-ordinary constraints on RPV parameter space. Even if R-parity violating couplings are real, CKM phase does induce RPV contribution and for some cases such a contribution is as strong as contribution from phases in the R-parity violating couplings.Hence, we have bounds directly on $|B_i \lambda^{\prime}_{ij1}|$ even if the RPV parameters are all real. Interestingly, even if slepton mass and/or $\mu_0$ is as high as 1 TeV, it still leads to neutron EDM that is an order of magnitude larger than the sensitivity at Los Alamos experiment. Since the results are not much sensitive to $\tan \beta$, our constraints will survive even if other observables tighten the constraints on $\tan \beta$.