On the family discrimination in 331-model

TL;DR

This paper investigates how the choice of differently treated quark generation in 331-models affects flavor structure and how experiments can identify this generation, considering exotic quark mixing and Higgs interactions.

Contribution

It provides a detailed analysis of flavor effects in 331-models with exotic quarks, including the impact of generation choice and mixing effects often neglected in previous studies.

Findings

The discriminated generation can be deduced from experimental data.

Flavor violating Higgs couplings are suppressed at 125 GeV.

Exotic quark mixing significantly influences flavor structure.

Abstract

In the so-called 331-models the gauge anomalies cancel only if there are three generations of fermions. This requires one of the quark generations to be in a different representation than the other two. But which generation is treated differently? In this work we study how the choice of differently treated generation effects the quark flavour structure and how the discriminated generation can be deduced from experiments. We study a general model based on $\beta=-1/\sqrt{3}$, which contains exotic quarks with same electric charges as SM quarks. We take fully into account the effects from exotic quark mixing with the SM quarks, which is often omitted in literature. We will also pay particular attention to $125$ GeV Higgs, and show analytically why its flavour violating couplings between SM quarks are suppressed.