Non-Gaussian fingerprints of self-interacting curvaton

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 NL and g 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 NL ∼ r dec −1 and g NL ∼ r dec −1 valid for quadratic curvaton potentials, where r dec measures the curvaton contribution to the total energy density at the time of its decay. Even if r dec ≪ 1, there always exists regions with f NL ∼ 0 since the sign of f NL oscillates as a function of the parameters. While g NL can also change sign, typically g NL is non-zero in the low- f NL regions. Hence, for some parameters the non-Gaussian statistics is dominated by g NL rather than by f NL . Due to self-interactions, both the relative signs of f NL and g NL and the functional relation between them is typically modified from the quadratic case, offering a possible experimental test of the curvaton interactions.