232 research outputs found
Cosmological Constraints on Isocurvature and Tensor Perturbations
We investigate cosmological constraints on primordial isocurvature and tensor
perturbations, using recent observations of the cosmic microwave background and
the large scale structure. We find that present observations are consistent
with purely adiabatic initial conditions for the structure formation under any
priors on correlations of isocurvature modes, and upper limits on the
contribution of isocurvature and tensor perturbations are presented. We also
apply the obtained constraints to some specific theoretical models, axion
isocurvature perturbation models and curvaton models, and give some
implications for theoretical models.Comment: 24 pages, 8 figure
CMB Constraint on Dark Matter Annihilation after Planck 2015
We update the constraint on the dark matter annihilation cross section by
using the recent measurements of the CMB anisotropy by the Planck satellite. We
fully calculate the cascade of dark matter annihilation products and their
effects on ionization, heating and excitation of the hydrogen, hence do not
rely on any assumption on the energy fractions that cause these effects.Comment: 9 pages, 1 figure; to appear in Phys.Lett.
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