Composite quarks and leptons with embedded QCD
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) PS ×𝑆𝑈(2) 𝐿 ×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) PS slows down the running of 𝛼 𝑠 in the UV. We estimate the effects of the strongly coupled 𝑆𝑈(15) dynamics on the running of the 𝑆𝑈(4) PS ×𝑆𝑈(2) 𝐿 ×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 six-preon bound states.