Textures and semi-local strings in supersymmetric hybrid inflation

Abstract

Global topological defects may account for the large cold spot observed in the cosmicmicrowave background. We explore possibilities for constructing models of supersymmetricF-term hybrid inflation, where the waterfall fields are globallySU(2)-symmetric. In contrastto the case where SU(2) is gauged, there arise Goldstone bosons and additional moduli, which are lifted only bymasses of soft supersymmetry breaking scale. The model predicts the existence of globaltextures, which can become semi-local strings if the waterfall fields are gauged underU(1)X. Gravitino overproduction can be avoided if reheating proceeds via the lightSU(2)-modes or right-handed sneutrinos. For values of the inflaton–waterfall coupling , the symmetry breaking scale imposed by normalization of the power spectrumgenerated from inflation coincides with the energy scale required to explain the mostprominent of the cold spots. In this case, the spectrum of density fluctuations isclose to scale invariant, which can be reconciled with measurements of the powerspectrum by the inclusion of the sub-dominant component due to the topologicaldefects.