We study the scale dependence of the non-linearity parameters fNL and gNL in curvaton models with self-interactions. We show that the spectral indices nfNL = d ln|fNL|/d ln k and ngNL = d ln|gNL|/d ln k can take values much greater than the slow-roll parameters and the spectral index of the power spectrum. This means that the scale-dependence of the bi and trispectrum could be easily observable in this scenario with Planck, which would lead to tight additional constraints on the model. Inspite of the highly non-trivial behaviour of fNL and gNL in the curvaton models with self-interactions, we find that the model can be falsified if gNL(k) is also observed.
Journal of Cosmology and Astroparticle Physics
- Pub Date:
- November 2011
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- High Energy Physics - Theory
- 19 pages, many figures. v2: Figure 4 replaced with a corrected normalisation, conclusions unchanged. Matches version published in JCAP