Tachyon Mediated Non-Gaussianity
arXiv:0805.1229 · doi:10.1103/PhysRevD.78.083522
Abstract
We describe a general scenario where primordial non-Gaussian curvature perturbations are generated in models with extra scalar fields. The extra scalars communicate to the inflaton sector mainly through the tachyonic (waterfall) field condensing at the end of hybrid inflation. These models can yield significant non-Gaussianity of the local shape, and both signs of the bispectrum can be obtained. These models have cosmic strings and a nearly flat power spectrum, which together have been recently shown to be a good fit to WMAP data. We illustrate with a model of inflation inspired from intersecting brane models.
6 pages; v3 discussion about loops included, shape of the intrinsic contribution corrected, references added
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