Selection rules in a unified gauge model of leptons and hadrons

Abstract

Decay modes and lifetimes of quarks, vector mesons and protons are determined for the unified model of leptons and hadrons recently proposed by Pati and Salam. It is found that while both the quarks and gauge mesons decay too rapidly to be observed, protons will be comfortably stable against decay into leptons, consistent with earlier estimates and existing experimental evidence. It is of special interest that while quarks may not be directly observable, their presence may be verified owing to the uniqueness of their preferred decay into quite a large number of pions. We also discuss an anomalous lepton-hadron scattering process whose occurrence would imply the presence of exotic SU(4) gluons carrying both baryon and lepton number.