Effects of $A_t$ and $\mu$ phases on B and K physics in the effective supersymmetric models

TL;DR

This paper investigates how the complex phases of $A_t$ and $ta$ in effective supersymmetric models influence B and K meson physics, revealing limited phase effects on mixing but significant potential for CP violation in certain decay processes.

Contribution

It provides a detailed analysis of the impact of $A_t$ and $ta$ phases on B and K physics observables within effective SUSY models, considering EDM constraints and contrasting with minimal supergravity scenarios.

Findings

No large phase shift in $B^0 - ar{B^0}$ mixing from $A_t$ and $ta$ phases.

CP asymmetry in dilepton events is below 0.1%.

Direct CP violation in $B\to X_s \gamma$ can reach about 16%.

Abstract

In the minimal supersymmetric standard model (MSSM), the $\mu-$parameter and the trilinear coupling $A_t$ may be generically complex and can affect various observables at B factories. Working in the effective SUSY models and imposing the edm constraints from Chang-Keung-Pilaftsis (CKP) mechanism, we find that (i) there is no new large phase shift in the $B^0 - \bar{B^0}$ mixing from the A_t and $\mu$ phases, (ii) CP violating dilepton asymmetry is smaller than 0.1%, (iii) the direct CP violation in $B\to X_s \gamma$ can be as large as $\sim \pm 16 %$, (iv) the ${\rm Br} (B\to X_s l^+ l^-)$ can be enhanced by upto $\sim 85 %$ compared to the standard model (SM) prediction, and its correlation with ${\rm Br} (B \to X_s \gamma)$ is distinctly different from the minimal supergravity scenario. Also, we find $1 \leq \epsilon_K / \epsilon_K^{SM} \leq 1.4$, and $\epsilon_K$ cannot be saturated by the A_t and $\mu$ phases alone : namely, $|\epsilon_K^{\rm SUSY}| \leq O(10^{-5})$ if the phases of $\mu$ and A_t are the sole origin of CP violation.