Early SU(4)PS-bar SU(2)L-bar SU(2)R-bar SU(2)H unification of quarks and leptons

We discuss various aspects of the early petite unification (PUT) of quarks and leptons based on the gauge group GPUT=SU(4)PS-bar SU(2)L-bar SU(2)R-bar SU(2)H. This unification takes place at the scale M=O(1-2-bar TeV) and gives the correct value of sin2θW(MZ2) without the violation of the upper bound on the KL->μe rate and the limits on FCNC processes. These properties require the existence of three new generations of unconventional quarks and leptons with charges up to 4/3 (for quarks) and 2 (for leptons) and masses O(250-bar GeV) in addition to the standard three generations of quarks and leptons. The horizontal group SU(2)H connects the standard fermions with the unconventional ones. We work out the spontaneous symmetry breaking (SSB) of the gauge group GPUT down to the SM gauge group, generalize the existing one-loop renormalization group (RG) analysis to the two-loop level including the contributions of Higgs scalars and Yukawa couplings, and demonstrate that the presence of three new generations of heavy unconventional quarks and leptons with masses O(250-bar GeV) is consistent with astrophysical constraints. The NLO and Higgs contributions to the RG analysis are significant while the Yukawa contributions can be neglected