Consequences of MSSM curvatons

Curvaton is an effectively massless field whose energy density during inflation is negligible but which later becomes dominant. During inflation the curvaton receives isocurvature perturbations, which at the decay are converted to adiabatic, scale invariant perturbations. A natural particle physics candidate for the curvaton could be a flat direction of the minimally supersymmetric standard model (MSSM), along which the renormalizable potential of squarks and sleptons vanishes. One can show that the requirements of late domination and the absence of damping of the perturbations pick out the n=9QuQue direction as almost a unique candidate for the MSSM curvaton. However, one must require that inflation takes place in a hidden sector decoupled from the Standard Model degrees of freedom. If most of the inflaton energy density can be radiated into extra dimensions, the simplest flat direction consisting of the Higgses Hu and Hd would provide a working example of an MSSM curvaton.