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Journal of Cosmology and Astroparticle Physics 08 (2011) 025
Beauty is distractive: particle production during multifield inflation
D. Battefeld, T. Battefeld, C. Byrnes, D. Langlois1

We consider a two-dimensional model of inflation, where the inflationary trajectory is ''deformed'' by a grazing encounter with an Extra Species/Symmetry Point (ESP) after the observable cosmological scales have left the Hubble radius. The encounter entails a sudden production of particles, whose backreaction causes a bending of the trajectory and a temporary decrease in speed, both of which are sensitive to initial conditions. This ''modulated'' effect leads to an additional contribution to the curvature perturbation, which can be dominant if the encounter is close. We compute associated non-Gaussianities, the bispectrum and its scale dependence as well as the trispectrum, which are potentially detectable in many cases. In addition, we consider a direct modulation of the coupling to the light field at the ESP via a modulaton field, a mixed scenario whereby the modulaton is identified with a second inflaton, and an extended Extra Species Locus (ESL); all of these scenarios lead to similar additional contributions to observables. We conclude that inflaton interactions throughout inflation are strongly constrained if primordial non-Gaussianities remain unobserved in current experiments such as PLANCK. If they are observed, an ESP encounter leaves additional signatures on smaller scales which may be used to identify the model.
1 :  APC - UMR 7164 - AstroParticule et Cosmologie
Physique/Relativité Générale et Cosmologie Quantique

Physique/Physique des Hautes Energies - Théorie
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