6533b821fe1ef96bd127c44c
RESEARCH PRODUCT
Dark Radiation and Inflationary Freedom after Planck 2015
Stefano GariazzoElena GiusarmaElena GiusarmaM. GerbinoM. GerbinoM. GerbinoEleonora Di ValentinoOlga Menasubject
PhysicsParticle physicsSterile neutrinoCosmology and Nongalactic Astrophysics (astro-ph.CO)010308 nuclear & particles physicsScalar (mathematics)Cosmic microwave backgroundSpectral densityFOS: Physical sciences01 natural sciencessymbols.namesakeHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)Dark radiation0103 physical sciencessymbolsPlanckNeutrino010306 general physicsAxionAstrophysics - Cosmology and Nongalactic Astrophysicsdescription
The simplest inflationary models predict a primordial power spectrum (PPS) of the curvature fluctuations that can be described by a power-law function that is nearly scale-invariant. It has been shown, however, that the low-multipole spectrum of the CMB anisotropies may hint the presence of some features in the shape of the scalar PPS, which could deviate from its canonical power-law form. We study the possible degeneracies of this non-standard PPS with the neutrino anisotropies, the neutrino masses, the effective number of relativistic species and a sterile neutrino or a thermal axion mass. The limits on these additional parameters are less constraining in a model with a non-standard PPS when only including the temperature auto-correlation spectrum measurements in the data analyses. The inclusion of the polarization spectra noticeably helps in reducing the degeneracies, leading to results that typically show no deviation from the $\Lambda$CDM model with a standard power-law PPS.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-04-28 |