Trispectrum estimator in equilateral type non-Gaussian models
- Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom)
We investigate an estimator to measure the primordial trispectrum in equilateral type non-Gaussian models such as k-inflation, single field DBI inflation and multi-field DBI inflation models from Cosmic Microwave Background (CMB) anisotropies. The shape of the trispectrum whose amplitude is not constrained by the bispectrum in the context of effective theory of inflation and k-inflation is known to admit a separable form of the estimator for CMB anisotropies. We show that this shape is 87% correlated with the full quantum trispectrum in single field DBI inflation, while it is 33% correlated with the one in multi-field DBI inflation when curvature perturbation is originated from purely entropic contribution. This suggests that g{sub NL}{sup equil}, the amplitude of this particular shape, provides a reasonable measure of the non-Gaussianity from the trispectrum in equilateral non-Gaussian models. We relate model parameters such as the sound speed, c{sub s} and the transfer coefficient from entropy perturbations to the curvature perturbation, T{sub RS} with g{sub NL}{sup equil}, which enables us to constrain model parameters in these models once g{sub NL}{sup equil} is measured in WMAP and Planck.
- OSTI ID:
- 22275337
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2010, Issue 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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