Left-left squark mixing in $K^+\rightarrow\pi^+\nu\bar{\nu}$ and minimal SUSY

TL;DR

This paper investigates how left-left squark mixing influences the rare decay $K^+ ightarrow \pi^+ uar{ u}$ in minimal supersymmetry with large $ aneta$, highlighting potential measurable effects and constraints from upcoming experiments.

Contribution

It demonstrates that significant effects on the decay rate can arise from left-left squark mixing combined with large trilinear couplings, providing new insights into flavor structure constraints.

Findings

Measurable effects possible for large $A_{\tilde{t}}$ and off-diagonal $LL$-insertions

Correlation between stop masses and $A_{\tilde{t}}$ considering Higgs mass constraints

Potential to constrain squark flavor mixing from decay measurements

Abstract

We analyze the role of the left-left squark mixing in the rare $K^+ \rightarrow \pi^+\nu\bar{\nu}$ decay within the minimal supersymmetry with a large $\tan\beta$. A Higgs boson mass of 125 GeV has been taken into account leading to correlation between stop masses and trilinear soft supersymmetry breaking coupling $A_{\tilde{t}}$. We find that measurable effects, similar to that of the well known $LR$ squark mixing terms, are possible for large $A_{\tilde{t}}$ combined with the off-diagonal $LL$-insertions. Precise measurements of the decay rate are expected from the ongoing NA62 experiment at CERN. We emphasize that the effect we present can put certain limits on the left-left flavor changing structure of the squark mass matrix.