An SU(5) × U(1)′ SUSY GUT with a “vector-like chiral” fourth family to fit all low energy data, including the muon g − 2

Abstract

An additional generation of quarks and leptons and their SUSY counterparts, which are vector-like under the Standard Model gauge group but are chiral with respect to the new U(1)3−4 gauge symmetry, are added to the Minimal Supersymmetric Standard Model (MSSM). We show that this model is a GUT and unifies the three SM gauge couplings and also the additional U(1)3−4 coupling at a GUT scale of ≈ 5 × 1016 GeV and explains the experimentally observed deviation of the muon g – 2. We also fit the quark flavor changing processes consistent with the latest experimental data and look at the effect of the new particles on the W boson mass without obviously conflicting with the observed masses of particles, CKM matrix elements, neutrino mixing angles, their mass differences, and the lepton-flavor violating bounds. This model predicts sparticle masses less than 25 TeV, with a gluino mass ≈ 2.3 – 3 TeV consistent with constraints, and one of the neutralinos as the LSP with a mass of ≈ 480 – 580 GeV, which is a potential dark matter candidate. The model is string theory motivated and predicts the VL quarks, leptons, a massive Z′ and two Dirac neutrinos at the TeV scale and the branching ratios of μ ⟶ eγ, τ ⟶ μγ and τ ⟶ 3μ with BR(μ ⟶ eγ) within reach of future experiments.