Lepton number as the fourth "color"

Abstract

Universal strong, weak, and electromagnetic i~teractions of leptons and hadrons are generated by gauging a non-Abelian renormalizable anomaly-free subgroup of the fundamental symmetry structure SU(4)& x SU(4)& x SU(4'), which unites three quartets of "colored" baryonic quarks and the quartet of known leptons into 16-folds of chiral fermionic multiplets, with lepton number treated as the fourth "color" quantum number. Experimental consequences of this scheme are discussed. These include (1) the emergence and effects of exotic gauge mesons carrying both baryonic as well as leptonic quantum numbers, particularly in semileptonic processes, (2) the manifestation of anomalous strong interactions among leptonic and semileptonic processes at high energies, (3) the independent possibility of baryon-lepton number violation in quark and proton decays, and (4) the occurrence of (V+A} weak-current effects.

Predicting neutrino parameters from SO(3) family symmetry and quark-lepton unification

“…The model is a supersymmetric theory based on the family symmetry SO(3) together with the Pati-Salam gauge group [23] …”

“…To achieve the alignment of φ 23 requires two fields φ 23 ,φ 23 . The purpose of the terms in Eq.B.30 is to drive non-zero VEVs for these two fields in the (2, 3) directions, and taken together with the positive soft mass squared terms, 6 lead to a potential which is minimised when magnitudes of the VEVs along each of the directions is equal, for each of the two fields φ 23 ,φ 23 separately.…”

Neutrinoless double-beta decay and physics beyond the standard model

“…As a first example of a model incorporating a rich phenomenology of lepton number violation, we will discuss the minimal Left-Right symmetric model (LRSM) which extends the Standard Model gauge symmetry to the group SU(2) L ⊗ SU(2) R ⊗ U(1) B−L [46][47][48][49]. Righthanded neutrinos are a necessary ingredient to realize this extended symmetry and are part of an SU(2) R doublet.…”

NLO corrections to lepton pair production beyond the Standard Model at hadron colliders

“…Examples include the replication of the fermion families, the naturalness problem associated with the Higgs scale, charge quantization, the baryon asymmetry in the universe, the presence of dark matter etc.. Clearly, an answer to such vital questions may be obtained only in a model much more ambitious than the SM. Candidates for the role include, amongst others, supersymmetry [1], grand unification [2,3] (with or without supersymmetry), family symmetries (gauged or otherwise) and compositeness for quarks and leptons [4]. In general, each such scenario (with its peculiar strengths and weaknesses) is associated with an individual set of tell-tale signatures.…”