EDM Constraints in Supersymmetric Theories

TL;DR

The paper evaluates how current EDM bounds, including the stringent mercury constraint, restrict CP violation in supersymmetric theories. It analyzes both 1-loop SUSY contributions and two-loop Barr-Zee effects within a framework of complex soft terms and multiple physical CP phases, including the Weinberg operator. It assesses four suppression channels—small CP phases, heavy sfermions, EDM cancellations, and flavour-off-diagonal CP violation—and finds that the mercury bound drastically reduces viable cancellation regions, leaving approximate CP symmetry or flavour-off-diagonal CP violation as the remaining attractive options. The results have significant implications for SUSY model-building, the plausibility of baryogenesis within SUSY, and potential CP-violating signals in flavor and collider experiments.

Abstract

We systematically analyze constraints on supersymmetric theories imposed by the experimental bounds on the electron, neutron, and mercury electric dipole moments. We critically reappraise the known mechanisms to suppress the EDMs and conclude that only the scenarios with approximate CP-symmetry or flavour-off-diagonal CP violation remain attractive after the addition of the mercury EDM constraint.

Figures (18)

• Figure 1: Leading SUSY contributions to the EDMs. The photon and gluon lines are to be attached to the loop in all possible ways.
• Figure 2: Barr-Zee type contributions to the EDMs.
• Figure 3: Embedding the SM gauge group within different sets of D-branes. The extra $D_q$ brane ($5_2$) is marked by a cross.
• Figure 4: Barr-Zee and Weinberg operator induced EDMs as a function of $\tan\beta$. 1 -- electron Barr-Zee EDM, 2 -- neutron Barr-Zee EDM, 3 -- neutron EDM due to the Weinberg operator. Here $m_0=m_{1/2}=A=200$ GeV, $\phi_{\mu}=0$, $\phi_A=\pi/2$.
• Figure 5: Barr-Zee and Weinberg operator induced EDMs as a function of $\tan\beta$. 1 -- electron Barr-Zee EDM, 2 -- neutron Barr-Zee EDM, 3 -- neutron EDM due to the Weinberg operator. Here $m_0=500$ GeV, $m_{1/2}=200$ GeV, $A=600$ GeV, $\phi_{\mu}=0$, $\phi_A=\pi/2$.