Supersymmetric Models with Approximate CP

TL;DR

This paper explores supersymmetric models with approximate CP violation, where small CP-violating effects arise naturally from high-energy symmetry breaking, leading to distinctive predictions for CP violation observables that are challenged by recent experimental data.

Contribution

It introduces a framework where supersymmetric models with approximate CP symmetry naturally generate small CP violation effects through spontaneous symmetry breaking at different scales.

Findings

Supersymmetric contributions can account for the $oldsymbol{\e_K}$ parameter.

Predictions for CP violation in B decays and rare K decays differ significantly from the Standard Model.

The framework is disfavored by recent measurements of $oldsymbol{\e^ extprime_{K}/ extepsilon_{K}}$.

Abstract

Supersymmetric models with an approximate CP, $10^{-3} \lsim \phi_{CP} \ll 1$, are a viable framework for the description of nature. The full high energy theory has exact CP and horizontal symmetries that are spontaneously broken with a naturally induced hierarchy of scales, $\Lambda_{CP} \ll \Lambda_{H}$. Consequently, the effective low energy theory, that is the supersymmetric Standard Model, has CP broken explicitly but by a small parameter. The $\epsilon_{K}$ parameter is accounted for by supersymmetric contributions. The predictions for other CP violating observables are very different from the Standard Model. In particular, CP violating effects in neutral B decays into final CP eigenstates such as $B \to \psi K_{S}$ and in $K \to \pi\nu\bar{\nu}$ decays are very small. This framework, though, is strongly disfavored by the recent measurements of $\epsilon^\prime_{K}/\epsilon_{K}$.