Dark radiation from particle decay: cosmological constraints and opportunities

Hasenkamp, Jasper; Kersten, Jörn

doi:10.1088/1475-7516/2013/08/024

Cited by 70 publications

(73 citation statements)

References 103 publications

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“…The density of the parent particle is allowed to vary between models in order to obtain the same amount of additional relativistic energy regardless of the other specified parameters, and they derive limits based on the current observed cold and hot dark matter densities. However, Hasenkamp and Kersten [39] make a number of simplifying assumptions. More specifically, they assume a sudden transition from radiation to matter domination, that the massive daughter particle is relativistic unless it's momentum is equal to or less than its mass, and that all the particles decay at a time equal to the lifetime τ .…”

Section: Resultsmentioning

confidence: 99%

Dark matter with two- and many-body decays and supernovae type Ia

Blackadder

Koushiappas

2014

Phys. Rev. D

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We present a decaying dark matter scenario where the daughter products are a single massless relativistic particle and a single, massive but possibly relativistic particle. We calculate the velocity distribution of the massive daughter particle and its associated equation of state and derive its dynamical evolution in an expanding Universe. In addition, we present a model of decaying dark matter where there are many massless relativistic daughter particles together with a massive particle at rest. We place constraints on these two models using supernovae type Ia observations. We find that for a daughter relativistic fraction of 1% and higher, lifetimes of at least less than 10 Gyrs are excluded, with larger relativistic fractions constraining longer lifetimes.PACS numbers: 97.60.Bw, 95.35.+d

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Section: Resultsmentioning

confidence: 99%

Dark matter with two- and many-body decays and supernovae type Ia

Blackadder

Koushiappas

2014

Phys. Rev. D

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“…More generally the additional radiation does not need to be fully thermalized, for example there are many possible models of non-thermal radiation production via particle decays (see, e.g., Hasenkamp & Kersten 2013;Conlon & Marsh 2013). The radiation could also be produced at temperatures T > 100 MeV, in which case typically ∆N eff < 1 for each additional species, since heating by photon production at muon annihilation (corresponding to T ≈ 100 MeV) decreases the fractional importance of the additional component at the later times relevant for the CMB.…”

Section: Constraints On N Effmentioning

confidence: 99%

Planck2015 results

Ade

Aghanim

Arnaud

et al. 2016

A&A

9,273

226

3,990

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This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted "base ΛCDM" in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H 0 = (67.8 ± 0.9) km s −1 Mpc −1 , a matter density parameter Ω m = 0.308 ± 0.012, and a tilted scalar spectral index with n s = 0.968 ± 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68% confidence limits on measured parameters and 95% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of τ = 0.066 ± 0.016, corresponding to a reionization redshift of z re = 8.8+1.7 −1.4 . These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base ΛCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find N eff = 3.15 ± 0.23 for the effective number of relativistic degrees of freedom, consistent with the value N eff = 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to m ν < 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with |Ω K | < 0.005. Adding a tensor component as a single-parameter extension to base ΛCDM we find an upper limit on the tensor-to-scalar ratio of r 0.002 < 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck (BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r 0.002 < 0.09 and disfavours inflationary models with a V(φ) ∝ φ 2 potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w = −1.006 ± 0.045, consistent with the expected Corresponding author: G. Efstathiou, e-mail: gpe@ast.cam.ac.ukArticle published by EDP Sciences A13, page 1 of 63 A&A 594, A13 (2016) value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundanc...

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“…See ref. [97] for an earlier discussion applied to gravitino DM. We assume an instantaneous transition between the relativistic and the non-relativistic regimes of the keV sterile neutrino, i.e.…”

Section: Jhep01(2015)006mentioning

confidence: 99%

A fresh look at keV sterile neutrino dark matter from frozen-in scalars

Adulpravitchai

Schmidt

2015

J. High Energ. Phys.

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Sterile neutrinos with a mass of a few keV can serve as cosmological warm dark matter. We study the production of keV sterile neutrinos in the early universe from the decay of a frozen-in scalar. Previous studies focused on heavy frozen-in scalars with masses above the Higgs mass leading to a hot spectrum for sterile neutrinos with masses below 8 − 10 keV. Motivated by the recent hints for an X-ray line at 3.55 keV, we extend the analysis to lighter frozen-in scalars, which allow for a cooler spectrum. Below the electroweak phase transition, several qualitatively new channels start contributing. The most important ones are annihilation into electroweak vector bosons, particularly W -bosons as well as Higgs decay into pairs of frozen-in scalars when kinematically allowed.

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Dark radiation from particle decay: cosmological constraints and opportunities

Cited by 70 publications

References 103 publications

Dark matter with two- and many-body decays and supernovae type Ia

Dark matter with two- and many-body decays and supernovae type Ia

Planck2015 results

A fresh look at keV sterile neutrino dark matter from frozen-in scalars

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