Dynamics of minimal supersymmetric standard model flatdirections consisting of multiple scalar fields

Abstract

Although often chosen because of simplicity, a single scalarfield does not provide a general parametrization of a minimalsupersymmetric standard model (MSSM) flat direction. We derive aformalism for a class of gauge invariant polynomials whichresult in a multifield description of flat directions. Incontrast to the single field case, the vanishing of the gaugecurrents yields an important dynamical constraint in themultifield framework. We consider in detail the example of theHuL flat direction and study the dynamical evolution duringand after inflation. We highlight the differences between thesingle and the multifield flat directions. We show that in themultifield case the field space has an intrinsic curvature andhence unsuppressed non-minimal kinetic terms for the flatdirection scalars arise. Also the phases of the individualcomponents evolve non-trivially right after inflation, charging thecomponents of the condensate and producing an enhanced entropyafter the decay of the condensate, which is due tocross-coupling of different lepton flavours in the F term.However, the qualitative features of the single fieldAffleck–Dine baryogenesis, such as the produced total charge,remain largely unchanged.