Large Scale Structure from the Higgs fields of the Supersymmetric Standard Model

We propose an alternative implementation of the curvaton mechanism for generating the curvature perturbations which does not rely on a late decaying scalar decoupled from inflation dynamics. In our mechanism the supersymmetric Higgs scalars are coupled to the inflaton in a hybrid inflation model, and this allows the conversion of the isocurvature perturbations of the Higgs fields to the observed curvature perturbations responsible for large scale structure to take place during reheating. We discuss an explicit model which realises this mechanism in which the $\mu$ term in the Higgs superpotential is generated after inflation by the vacuum expectation value of a singlet field. The main prediction of the model is that the spectral index should deviate significantly from unity, $\mathrm{\mid }n-1\mathrm{\mid }\sim 0.1$. We also expect relic isocurvature perturbations in neutralinos and baryons, but no significant departures from gaussianity and no observable effects of gravity waves in the CMB spectrum.