Primordial Non-Gaussianity in Models with Dark Matter Isocurvature Fluctuations

Abstract

We investigate primordial non-Gaussianity and dark matter isocurvature fluctuations in the modulated reheating and the curvaton scenarios. In these scenarios, large non-Gaussianity can be generated, on the other hand, depending on how dark matter is produced, too large isocurvature fluctuations can also arise, which is inconsistent with current observations. In this paper, we study this issue in a mixed scenario where the curvature fluctuations can also be produced from the inflaton fluctuations as well as those from a light scalar field such as the modulus and the curvaton. We show that primordial fluctuations can be highly non-Gaussian without conflicting the current constraint on isocurvature fluctuations for such mixed scenarios. However, if the constraint on isocurvature fluctuations becomes severer as expected by the Planck satellite, $f_{\mathrm{NL}}$, a nonlinearity parameter for adiabatic fluctuations, should be very small as $f_{\mathrm{NL}}\lesssim 3$, which would give interesting implications for the generation mechanism of dark matter. Non-Gaussianity from isocurvature fluctuations is also discussed in these scenarios.

26 pages, 4 figures, accepted for publication in PRD

References in corpus (19)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Big-Bang Nucleosynthesis and Gravitino
• Non-Gaussianity in the modulated reheating scenario
• Primordial trispectrum from inflation
• Moduli-Induced Gravitino Problem
• Optimal limits on f_{NL}^{local} from WMAP 5-year data
• Primordial Curvature Fluctuation and Its Non-Gaussianity in Models with Modulated Reheating
• Probing String Theory with Modulated Cosmological Fluctuations
• Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models
• Inflaton Decay in Supergravity
• The Gravitino-Overproduction Problem in Inflationary Universe
• A numerical study of non-gaussianity in the curvaton scenario
• Gravitinos from Heavy Scalar Decay
• Curvaton Dynamics and the Non-Linearity Parameters in Curvaton Model
• Large Non-Gaussianity Implication for Curvaton Scenario
• Correlated isocurvature perturbations from mixed inflaton-curvaton decay
• Isocurvature, non-gaussianity and the curvaton model
• Non-Gaussianity and Baryonic Isocurvature Fluctuations in the Curvaton Scenario
• Non-Gaussianity from Symmetry

Cited by in corpus (12)

• On Classification of Models of Large Local-Type Non-Gaussianity
• Scale-dependence of Non-Gaussianity in the Curvaton Model
• General treatment of isocurvature perturbations and non-Gaussianities
• Negative spectral index of $f_{NL}$ in the axion-type curvaton model
• Constraints on scalar and tensor perturbations in phenomenological and two-field inflation models: Bayesian evidences for primordial isocurvature and tensor modes
• Primordial Trispectrum from Isocurvature Fluctuations
• Isocurvature perturbations and tensor mode in light of Planck and BICEP2
• Modulated preheating and isocurvature perturbations
• New features in curvaton model
• Affleck-Dine baryogenesis with modulated reheating
• Refined Study of Isocurvature Fluctuations in the Curvaton Scenario
• Spectator fields and their imprints on the Cosmic Microwave Background