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Journal of Cosmology and Astroparticle Physics 02 (2011) 020
Primordial trispectrum from isocurvature fluctuations
D. Langlois1, T. Takahashi

We study non-Gaussianity generated by adiabatic and isocurvature primordial perturbations. We first obtain, in a very general setting, the non-linear perturbations, up to third order, for an arbitrary number of cosmological fluids, going through one or several decay transitions. We then apply this formalism to the mixed curvaton and inflaton model, allowing for several decay channels. We compute the various contributions to the bispectrum and trispectrum resulting from adiabatic and isocurvature perturbations, which are correlated in general. By investigating some hybrid decay scenario, we show that significant non-Gaussianity of adiabatic and isocurvature types can be generated without conflicting with the present isocurvature constraints from the power spectrum. In particular, we find cases where non-Gaussianity of isocurvature origin can dominate its adiabatic counterpart, both in the bispectrum and in the trispectrum.
1 :  APC - UMR 7164 - AstroParticule et Cosmologie
Physique/Physique des Hautes Energies - Phénoménologie

Physique/Physique des Hautes Energies - Théorie
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