Isocurvature perturbations in extra radiation
arXiv:1107.4962 · doi:10.1088/1475-7516/2012/02/022
Abstract
Recent cosmological observations, including measurements of the CMB anisotropy and the primordial helium abundance, indicate the existence of an extra radiation component in the Universe beyond the standard three neutrino species. In this paper we explore the possibility that the extra radiation has isocurvatrue fluctuations. A general formalism to evaluate isocurvature perturbations in the extra radiation is provided in the mixed inflaton-curvaton system, where the extra radiation is produced by the decay of both scalar fields. We also derive constraints on the abundance of the extra radiation and the amount of its isocurvature perturbation. Current observational data favors the existence of an extra radiation component, but does not indicate its having isocurvature perturbation. These constraints are applied to some particle physics motivated models. If future observations detect isocurvature perturbations in the extra radiation, it will give us a hint to the origin of the extra radiation.
41 pages, 8 figures; version accepted for publication in JCAP
References in corpus (44)
- Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
- Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Power Spectra and WMAP-Derived Parameters
- Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Sky Maps, Systematic Errors, and Basic Results
- A Measurement of the Damping Tail of the Cosmic Microwave Background Power Spectrum with the South Pole Telescope
- Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Foreground Emission
- The Atacama Cosmology Telescope: Cosmological Parameters from the 2008 Power Spectra
- The primordial abundance of 4He: evidence for non-standard big bang nucleosynthesis
- Cosmology seeking friendship with sterile neutrinos
- The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectrum at 148 and 218 GHz from the 2008 Southern Survey
- Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models
- A New Approach to Systematic Uncertainties and Self-Consistency in Helium Abundance Determinations
- Thermal axion production in the primordial quark-gluon plasma
- Fast Estimator of Primordial Non-Gaussianity from Temperature and Polarization Anisotropies in the Cosmic Microwave Background
- Constraining Isocurvature Initial Conditions with WMAP 3-year data
- Constraining The Early-Universe Baryon Density And Expansion Rate
- Solar neutrino spectrum, sterile neutrinos and additional radiation in the Universe
- Dark Radiation Emerging After Big Bang Nucleosynthesis?
- Curvaton Dynamics and the Non-Linearity Parameters in Curvaton Model
- Cosmological implications of supersymmetric axion models
- Cosmology of neutrinos and extra light particles after WMAP3
- Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis
- A theory of extra radiation in the Universe
- Evidence for extra radiation? Profile likelihood versus Bayesian posterior
- Mapping systematic errors in helium abundance determinations using Markov Chain Monte Carlo
- Limits on Isocurvature Perturbations from Non-Gaussianity in WMAP Temperature Anisotropies
- Hilltop Non-Gaussianity
- Cosmological Constraints on Neutrino Injection
- Probing the Effective Number of Neutrino Species with Cosmic Microwave Background
- Thermal inflation, baryogenesis and axions
- The Atacama Cosmology Telescope: Calibration with WMAP Using Cross-Correlations
- Non-Gaussianity from Baryon Asymmetry
- General treatment of isocurvature perturbations and non-Gaussianities
- Negative spectral index of in the axion-type curvaton model
- Axionic Mirage Mediation
- WMAP 5-year constraints on lepton asymmetry and radiation energy density: Implications for Planck
- Cosmological Constraints on Isocurvature and Tensor Perturbations
- Hunting for Isocurvature Modes in the CMB non-Gaussianities
- Solving Cosmological Problems of Supersymmetric Axion Models in an Inflationary Universe
- Are priors responsible for cosmology favoring additional neutrino species?
- Differentiating CDM and Baryon Isocurvature Models with 21 cm Fluctuations
- Non-Gaussian isocurvature perturbations in dark radiation
- Primordial Trispectrum from Isocurvature Fluctuations
- Fundamental Uncertainty in the BAO Scale from Isocurvature Modes
- Neutrinos, WMAP, and BBN
Cited by in corpus (17)
- Axions : Theory and Cosmological Role
- CMB spectral distortions from small-scale isocurvature fluctuations
- Probing dark radiation with inflationary gravitational waves
- Free-streaming and Coupled Dark Radiation Isocurvature Perturbations: Constraints and Application to the Hubble Tension
- CMB constraint on non-Gaussianity in isocurvature perturbations
- Axino dark matter with R-parity violation and 130 GeV gamma-ray line
- Cosmological constraints on axionic dark radiation from axion-photon conversion in the early Universe
- Dark Radiation from Modulated Reheating
- Non-Gaussian isocurvature perturbations in dark radiation
- Charged Q-balls in gauge mediated SUSY breaking models
- Constraints on neutrino density and velocity isocurvature modes from WMAP-9 data
- Diraxiogenesis
- Anisotropic CMB distortions from non-Gaussian isocurvature perturbations
- Extended analysis of CMB constraints on non-Gaussianity in isocurvature perturbations
- BBN constraints on dark radiation isocurvature
- Generalized neutrino isocurvature
- Cosmological perturbation theory with trinity of scalar fields