Inverse seesaw and inflation in a supersymmetric 331 model from $SU(6)$

Abstract

We propose a $N=1$ supersymmetric $SU(6)$ theory with an intermediate $(SU(3)_C\times SU(3)_L\times U(1)_X)$ phase, in which common fields and operators relate the neutrinos, gauge mediation, unification, and symmetry-breaking sectors. The inverse-seesaw Dirac matrix is antisymmetric and thus has rank two, leaving one massless neutrino at leading order. The leading symmetry-allowed correction lifts this zero mode through its projection onto the left and right null vectors of the Dirac matrix, resulting in a quartic suppression by the ratio of the intermediate and ultraviolet scales. The complete unified messenger multiplets preserve the relative one-loop gauge-coupling crossing, while the supersymmetry-breaking spurion entering the messenger sector also determines the scale of lepton-number violation. The coupling governing (331) breaking fixes both the inflationary normalization and the radial mass in the broken vacuum. For the conditional heavy spectrum adopted in the threshold calculations, the gauge couplings remain perturbative. The physical scalar directions transverse to the inflaton are stable within the neutral $((\Phi,\bar\Phi,S))$ subspace. These results provide the analytical scale relations among the inverse seesaw, messenger sector, unified gauge evolution, and inflation, while keeping the assumptions associated with the ultraviolet Higgs and heavy-threshold sectors explicitly.