Composite quarks and leptons with embedded QCD

TL;DR

This paper proposes a model where quarks and leptons are composite particles formed from preons, with an $SU(15)$ gauge interaction, leading to new predictions for collider physics and gauge coupling behaviors.

Contribution

It introduces a novel $SU(15)$ gauge-based composite model for quarks and leptons, embedding QCD and predicting TeV-scale composite states and extended Higgs sectors.

Findings

Composite vectorlike lepton doublet at TeV scale

Gauge couplings likely remain perturbative beyond compositeness scale

Extended Higgs sector from 6-preon bound states

Abstract

We construct a model of quark and lepton compositeness based on an $SU(15)$ gauge interaction that confines chiral preons, which are also charged under the weakly-coupled $SU(4)_{\rm PS} \times SU(2)_L\times SU(2)_R$ gauge group. The breaking of the latter, down to the Standard Model group, is achieved by scalar $SU(15)$ bound states at a scale in the $30 - 100$ TeV range. The embedding of the QCD gauge group in $SU(4)_{\rm PS} $ slows down the running of $\alpha_s$ in the UV. We estimate the effects of the strongly-coupled $SU(15)$ dynamics on the running of the $SU(4)_{\rm PS} \times SU(2)_L\times SU(2)_R$ gauge couplings, which likely remain perturbative beyond the compositeness scale of about $10^3 - 10^4$ TeV, and even above a unification scale. A composite vectorlike lepton doublet acquires a mass in the TeV range probed at future colliders, and an extended Higgs sector arises from 6-preon bound states.