Composite quarks and leptons with embedded QCD

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 $SU(4{)}_{\mathrm{PS}}\times SU(2{)}_L\times SU(2{)}_R$ 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 $SU(4{)}_{\mathrm{PS}}$ slows down the running of $\hat{I}{\pm }_s$ in the UV. We estimate the effects of the strongly-coupled $SU(15)$ dynamics on the running of the $SU(4{)}_{\mathrm{PS}}\times SU(2{)}_L\times SU(2{)}_R$ 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.

34 pages, 6 figures. v2: new section 2.2 on the preonic chiral dynamics; expanded analysis of the phenomenology of composite vectorlike leptons, and of the composite Higgs sector