Bs Mixing and Electric Dipole Moments in MFV

TL;DR

This paper investigates four-fermion operators within Minimal Flavor Violation that can induce CP-violation in Bs mixing and estimates their impact on electric dipole moments, highlighting their potential experimental signatures.

Contribution

It identifies specific operators affecting Bs mixing and EDMs, classifies them based on their dependence on quark mixing, and discusses possible UV completions.

Findings

Operators can enhance Bs mixing significantly.

EDMs from certain operators may exceed experimental bounds.

Some operators predict EDMs below current detection limits.

Abstract

We analyze the general structure of four-fermion operators capable of introducing CP-violation preferentially in Bs mixing within the framework of Minimal Flavor Violation. The effect requires a minimum of O(Yu^4 Yd^4) Yukawa insertions, and at this order we find a total of six operators with different Lorentz, color, and flavor contractions that lead to enhanced Bs mixing. We then estimate the impact of these operators and of their close relatives on the possible sizes of electric dipole moments (EDMs) of neutrons and heavy atoms. We identify two broad classes of such operators: those that give EDMs in the limit of vanishing CKM angles, and those that require quark mixing for the existence of non-zero EDMs. The natural value for EDMs from the operators in the first category is up to an order of magnitude above the experimental upper bounds, while the second group predicts EDMs well below the current sensitivity level. Finally, we discuss plausible UV-completions for each type of operator.