New features in curvaton model

Pravabati Chingangbam; Qing-Guo Huang

doi:10.1103/PhysRevD.83.023527

paper

New features in curvaton model

arXiv:1006.4006 · doi:10.1103/PhysRevD.83.023527

Abstract

We demonstrate novel features in the behavior of the second and third order non-linearity parameters of the curvature perturbation, namely, $f_{N L}$ and $g_{N L}$ , arising from non-linear motion of curvaton field. We investigate two classes of potentials for the curvaton - the first has tiny oscillations super-imposed upon the quadratic potential. The second is characterized by a single 'feature' separating two quadratic regimes with different mass scales. The feature may either be a bump or a flattening of the potential. In the case of the oscillatory potential we find that as the width and height of superimposed oscillations increase, both $f_{N L}$ and $g_{N L}$ deviate strongly from their expected values from a quadratic potential. $f_{N L}$ changes sign from positive to negative as the oscillations in the potential become more prominent. Hence, this model can be severely constrained by convincing evidence from observations that $f_{N L}$ is positive. $g_{N L}$ , on the other hand, acquires very large negative values. For the the single feature potential, we find that $f_{N L}$ and $g_{N L}$ exhibit oscillatory behavior as a function of the parameter that controls the feature.

1+14 pages, 5 figures

New features in curvaton model

Abstract

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