Probing a panoply of curvaton-decay scenarios using CMB data

Abstract

In the curvaton scenario, primordial curvature perturbations are produced by a second field that is subdominant during inflation. Depending on how the curvaton decays [possibly producing baryon number, lepton number, or cold dark matter (CDM)], mixtures of correlated isocurvature perturbations are produced, allowing the curvaton scenario to be tested using cosmic microwave background (CMB) data. Here, a full range of 27 curvaton-decay scenarios is compared with CMB data, placing limits on the curvaton fraction at decay, r_D, and the lepton asymmetry, ξ_lep . If baryon number is generated by curvaton decay and CDM before (or vice versa), these limits imply specific predictions for non-Gaussian signatures testable by future CMB experiments and upcoming large-scale-structure surveys.