January 25 (Wed), 14:15 in A315   

Stefano Orani (Imperial College, London, UK)


Non-Gaussianity from the hybrid potential

I will discuss how the Hybrid inflationary potential can lead to observationally compatible predictions in a regime where the defect field is light, and more than 60 e-folds of accelerated expansion occur after the symmetry breaking transition. Considered in such a regime, the model is an example of hill-top mechanism, for which analytical expressions giving f_NL can be derived. Using these expressions as a guide, we identified parameters leading to significant non-Gaussianity and satisfying WMAP observational bounds. Focusing on a particular example leading to large fNL, I will discuss the likelihood of the initial conditions at horizon crossing.