Signatures of relativistic neutrinos in CMB anisotropy and matter clustering

Bashinsky, Sergei; Seljak, Uroš

doi:10.1103/physrevd.69.083002

Cited by 382 publications

(604 citation statements)

References 90 publications

Supporting

Mentioning

589

Contrasting

Order By: Relevance

“…There is thus an approximate degeneracy between these two parameters along which the ratio is nearly constant. The extent of the degeneracy is limited by the characteristic phase shift of the acoustic oscillations that arises due to the free streaming of the neutrinos (Bashinsky & Seljak 2004). As discussed by Hou et al (2013), the early ISW effect also partly breaks the degeneracy, but this is less important than the effect of the phase shifts.…”

Section: Extension To the Case With Extra Relativistic Relicsmentioning

confidence: 99%

“…The physics of how N eff is constrained by CMB anisotropies is explained in Bashinsky & Seljak (2004), Hou et al (2013) and Lesgourgues et al (2013). The main effect is that increasing the radiation density at fixed θ * (to preserve the angular scales of the acoustic peaks) and fixed z eq (to preserve the early-ISW effect and so first-peak height) increases the expansion rate before recombination and reduces the age of the Universe at recombination.…”

Section: Constraints On N Effmentioning

confidence: 99%

“…A striking illustration of the interplay between cosmology and particle physics is the potential of CMB observations to constrain the properties of relic neutrinos, and possibly of additional light relic particles in the Universe (see e.g., Dodelson et al 1996;Hu et al 1995;Bashinsky & Seljak 2004;Ichikawa et al 2005;Hannestad 2010). In the following subsections, we present Planck constraints on the mass of ordinary (active) neutrinos assuming no extra relics, on the density of light relics assuming they all have negligible masses, and finally on models with both light massive and massless relics.…”

Section: Neutrino Physics and Constraints On Relativistic Componentsmentioning

confidence: 99%

See 2 more Smart Citations

Planck2013 results. XVI. Cosmological parameters

Ade¹,

Aghanim²,

Armitage-Caplan³

et al. 2014

A&A

5,084

163

2,253

View full text Add to dashboard Cite

This paper presents the first cosmological results based on Planck measurements of the cosmic microwave background (CMB) temperature and lensing-potential power spectra. We find that the Planck spectra at high multipoles ( > ∼ 40) are extremely well described by the standard spatiallyflat six-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations. Within the context of this cosmology, the Planck data determine the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ * = (1.04147 ± 0.00062) × 10 −2 , Ω b h 2 = 0.02205 ± 0.00028, Ω c h 2 = 0.1199 ± 0.0027, and n s = 0.9603 ± 0.0073, respectively (note that in this abstract we quote 68% errors on measured parameters and 95% upper limits on other parameters). For this cosmology, we find a low value of the Hubble constant, H 0 = (67.3 ± 1.2) km s −1 Mpc −1 , and a high value of the matter density parameter, Ω m = 0.315 ± 0.017. These values are in tension with recent direct measurements of H 0 and the magnituderedshift relation for Type Ia supernovae, but are in excellent agreement with geometrical constraints from baryon acoustic oscillation (BAO) surveys. Including curvature, we find that the Universe is consistent with spatial flatness to percent level precision using Planck CMB data alone. We use high-resolution CMB data together with Planck to provide greater control on extragalactic foreground components in an investigation of extensions to the six-parameter ΛCDM model. We present selected results from a large grid of cosmological models, using a range of additional astrophysical data sets in addition to Planck and high-resolution CMB data. None of these models are favoured over the standard six-parameter ΛCDM cosmology. The deviation of the scalar spectral index from unity is insensitive to the addition of tensor modes and to changes in the matter content of the Universe. We find an upper limit of r 0.002 < 0.11 on the tensor-to-scalar ratio. There is no evidence for additional neutrino-like relativistic particles beyond the three families of neutrinos in the standard model. Using BAO and CMB data, we find N eff = 3.30 ± 0.27 for the effective number of relativistic degrees of freedom, and an upper limit of 0.23 eV for the sum of neutrino masses. Our results are in excellent agreement with big bang nucleosynthesis and the standard value of N eff = 3.046. We find no evidence for dynamical dark energy; using BAO and CMB data, the dark energy equation of state parameter is constrained to be w = −1.13 +0.13 −0.10 . We also use the Planck data to set limits on a possible variation of the fine-structure constant, dark matter annihilation and primordial magnetic fields. Despite the success of the six-parameter ΛCDM model in describing the Planck data at high multipoles, we note that this cosmology does not provide a good fit to the temperature power spectrum at low multipoles. T...

show abstract

Section: Extension To the Case With Extra Relativistic Relicsmentioning

confidence: 99%

Section: Constraints On N Effmentioning

confidence: 99%

Section: Neutrino Physics and Constraints On Relativistic Componentsmentioning

confidence: 99%

See 1 more Smart Citation

Planck2013 results. XVI. Cosmological parameters

Ade¹,

Aghanim²,

Armitage-Caplan³

et al. 2014

A&A

5,084

163

2,253

View full text Add to dashboard Cite

show abstract

“…If further data confirms this, it could suggest new dark matter such as a sterile neutrino [5] or a decaying particle [8][9][10], or nonstandard thermal history [11]. Or it could indicate that dark energy does not fade away to the ∼ 10 −9 fraction of the energy density at CMB recombination that is predicted by the cosmological constant.…”

mentioning

confidence: 99%

Limits on dark radiation, early dark energy, and relativistic degrees of freedom

et al. 2011

View full text Add to dashboard Cite

Recent cosmological data analyses hint at the presence of an extra relativistic energy component in the early universe. This component is often parametrized as an excess of the effective neutrino number N eff over the standard value of 3.046. The excess relativistic energy could be an indication for an extra (sterile) neutrino, but early dark energy and barotropic dark energy also contribute to the relativistic degrees of freedom. We examine the capabilities of current and future data to constrain and discriminate between these explanations, and to detect the early dark energy density associated with them. We find that while early dark energy does not alter the current constraints on N eff , a dark radiation component, such as that provided by barotropic dark energy models, can substantially change current constraints on N eff , bringing its value back to agreement with the theoretical prediction. Both dark energy models also have implications for the primordial mass fraction of Helium Yp and the scalar perturbation index ns. The ongoing Planck satellite mission will be able to further discriminate between sterile neutrinos and early dark energy.

show abstract

“…(See, for example, Refs. [16,17] for discussions of the effects of neutrinos on CMBR fluctuations. )…”

Section: •Neutrino Massesmentioning

confidence: 99%

Working group report: Neutrino and astroparticle physics

Agashe¹,

Bandyopadhyay²,

Bhattacharya³

et al. 2004

Pramana - J Phys

View full text Add to dashboard Cite

Abstract. This is the report of neutrino and astroparticle physics working group at WHEPP-8. We present the discussions carried out during the workshop on selected topics in the above fields and also indicate progress made subsequently. The neutrino physics subgroup studied the possibilites of constraining neutrino masses, mixing and CPT violation in lepton sector from future experiments. Neutrino mass models in the context of abelian horizontal symmetries, warped extra dimensions and in presence of triplet Higgs were studied. Effect of threshold corrections on radiative magnification of mixing angles was investigated. The astroparticle physics subgroup focused on how various particle physics inputs affect the CMBR fluctuation spectrum, and on brane cosmology. This report also contains an introduction on how to use the publicly available code CMBFAST to calculate the CMBR fluctuations.

show abstract

Signatures of relativistic neutrinos in CMB anisotropy and matter clustering

Cited by 382 publications

References 90 publications

Planck2013 results. XVI. Cosmological parameters

Planck2013 results. XVI. Cosmological parameters

Limits on dark radiation, early dark energy, and relativistic degrees of freedom

Working group report: Neutrino and astroparticle physics

Contact Info

Product

Resources

About