Non-Gaussian fingerprints of self-interacting curvaton

Journal Article · Thu Apr 01 04:00:00 EDT 2010 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2010/04/009· OSTI ID:22272846

Enqvist, Kari; Taanila, Olli ^[1]; Nurmi, Sami ^[2]; Takahashi, Tomo ^[3]

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1. Physics Department, University of Helsinki, FIN-00014 (Finland)
2. Institute for Theoretical Physics, University of Heidelberg, 69120 Heidelberg (Germany)
3. Department of Physics, Saga University, Saga 840-8502 (Japan)

We investigate non-Gaussianities in self-interacting curvaton models treating both renormalizable and non-renormalizable polynomial interactions. We scan the parameter space systematically and compute numerically the non-linearity parameters f{sub NL} and g{sub NL}. We find that even in the interaction dominated regime there are large regions consistent with current observable bounds. Whenever the interactions dominate, we discover significant deviations from the relations f{sub NL} ∼ r{sub dec}{sup −1} and g{sub NL} ∼ r{sub dec}{sup −1} valid for quadratic curvaton potentials, where r{sub dec} measures the curvaton contribution to the total energy density at the time of its decay. Even if r{sub dec} || 1, there always exists regions with f{sub NL} ∼ 0 since the sign of f{sub NL} oscillates as a function of the parameters. While g{sub NL} can also change sign, typically g{sub NL} is non-zero in the low-f{sub NL} regions. Hence, for some parameters the non-Gaussian statistics is dominated by g{sub NL} rather than by f{sub NL}. Due to self-interactions, both the relative signs of f{sub NL} and g{sub NL} and the functional relation between them is typically modified from the quadratic case, offering a possible experimental test of the curvaton interactions.

• OSTI ID: 22272846
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 04 Vol. 2010; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
COSMOLOGY
ENERGY DENSITY
POLYNOMIALS
POSTULATED PARTICLES
POTENTIALS
RENORMALIZATION
STATISTICS