Flavor Changing Neutral Higgs Bosons in a Supersymmetric Extension based on a $Q_6$ Family Symmetry

TL;DR

This paper explores a supersymmetric model with a $Q_6$ family symmetry that predicts flavor-changing neutral Higgs bosons, analyzing their effects on meson mass differences and identifying parameter ranges consistent with experimental constraints.

Contribution

It introduces a supersymmetric $Q_6$ family symmetry model that reduces Yukawa couplings and constrains FCNCs, providing predictions for heavy Higgs boson masses compatible with meson mixing data.

Findings

Heavy Higgs bosons must be heavier than ~1.5 TeV to satisfy constraints.

If the $ ext{Δ}M_K$ constraint is relaxed, Higgs bosons could be as light as ~0.4 TeV.

Model predictions are within the reach of LHC experiments.

Abstract

A supersymmetric extension of the standard model based on the discrete $Q_6$ family symmetry is considered, and we investigate flavor-changing neutral current (FCNC) processes, especially those mediated by heavy flavor-changing neutral Higgs bosons. Because of the family symmetry the number of the independent Yukawa couplings is smaller than that of the observed quantities such as the Cabibbo-Kobayashi-Maskawa matrix and the quark masses, so that the FCNCs can be parametrized only by the mixing angles and masses of the Higgs fields. We focus our attention on the mass differences of the neutral $K, D$ and $B$ mesons. All the constraints including that from the ratio $\Delta M_{B_s}/\Delta M_{B_d}$ can be satisfied, if the heavy Higgs bosons are heavier than $\sim 1.5$ TeV. If the constraint from $\Delta M_K$ is slightly relaxed, the heavy Higgs bosons can be as light as $\sim 0.4$ TeV, which is within the accessible range of LHC.