Cosmology Favoring Extra Radiation and Sub-eV Mass Sterile Neutrinos as an Option

Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.; Tamborra, Irene; Wong, Yvonne Y. Y.

doi:10.1103/physrevlett.105.181301

Cited by 222 publications

(192 citation statements)

References 49 publications

(51 reference statements)

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“…There is some tension between these limits and the best-fit masses of the sterile neutrinos that we adopt from Kopp et al (2011). However, we note that the limits in Hamann et al (2010) are derived assuming a flat universe with a cosmological constant, while we allow for both spatial curvature and a dark energy equation of state, w −1 in our analysis.…”

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

“…Specifically, N eff = 5 is within the allowed region (Hamann et al 2010;Dunkley et al 2010;Giusarma et al 2011). The allowed mass range of the sterile neutrinos has also been studied.…”

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

“…We assume that they were, since several studies (Hamann et al 2010;Melchiorri et al 2009;Kainulainen 1990) suggest that this was the case for the masses and mixing parameters we consider. This means that the standard relation between the sum of the neutrino masses and their contribution to the cosmic mass density parameter applies.…”

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

“…The allowed mass range of the sterile neutrinos has also been studied. In Hamann et al (2010) a scenario with massless flavour neutrinos and two thermalized sterile neutrinos with a common mass is investigated. Using a combination of different cosmological probes, including the CMB and the galaxy power spectrum, they find a 95% upper bound of 0.45 eV for each sterile neutrino.…”

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

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Reactor sterile neutrinos, dark energy, and the age of the universe

Kristiansen

Elgarøy

2011

A&A

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There are indications that the neutrino oscillation data from reactor experiments and the LSND and MiniBooNE experiments show a preference for two sterile neutrino species, both with masses in the eV region. We show that this result has a significant impact on some important cosmological parameters. Specifically, we use a combination of CMB, LSS, and SN1A data and show that the existence of two light, sterile neutrinos would rule out the cosmological constant as dark energy at a 95% confidence level and lower the expansion age of the universe to 12.58 ± 0.26 Gyr.

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Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

“…Specifically, N eff = 5 is within the allowed region (Hamann et al 2010;Dunkley et al 2010;Giusarma et al 2011). The allowed mass range of the sterile neutrinos has also been studied.…”

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

Section: Sterile Neutrinos and Cosmologymentioning

confidence: 99%

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Reactor sterile neutrinos, dark energy, and the age of the universe

Kristiansen

Elgarøy

2011

A&A

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“…These include: (i) models in which the extra relativistic degrees of freedom are related to possible dark matter candidates [25][26][27][28][29][30]; (ii) models based on active-sterile mixing of neutrinos in a heat bath [31,32]; (iii) models based on milli-weak interactions of right-handed partners of three Dirac neutrinos [7]. In this work we confine our discussion to case (iii).…”

mentioning

confidence: 99%

Right-handed neutrinos as the dark radiation: Status and forecasts for the LHC

2013

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Precision data from cosmology (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch) have hinted at the presence of extra relativistic degrees of freedom, the so-called "dark radiation." We present a model independent study to account for the dark radiation by means of the right-handed partners of the three, left-handed, standard model neutrinos. We show that milli-weak interactions of these Dirac states (through their coupling to a TeV-scale Z ′ gauge boson) may allow the νR's to decouple much earlier, at a higher temperature, than their left-handed counterparts. If the νR's decouple during the quark-hadron crossover transition, they are considerably cooler than the νL's and contribute less than 3 extra "equivalent neutrinos" to the early Universe energy density. For decoupling in this transition region, the 3 νR generate ∆Nν = 3(Tν R /Tν L ) 4 < 3, extra relativistic degrees of freedom at BBN and at the CMB epochs. Consistency with present constraints on dark radiation permits us to identify the allowed region in the parameter space of Z ′ masses and couplings. Remarkably, the allowed region is within the range of discovery of LHC14.

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Dark matter evidence, particle physics candidates and detection methods

Bergström¹

2012

Annalen der Physik

172

177

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The problem of the dark matter in the universe is reviewed. A short history of the subject is given, and several of the most obvious particle candidates for dark matter are identified. Particular focus is given to weakly interacting, massive particles (WIMPs) of which the lightest supersymmetric particle is an interesting special case and a useful template. The three detection methods: in particle accelerators, by direct detections of scattering in terrestrial detectors, and indirect detection of products from dark matter particle annihilation in the galactic halo, are discussed and their complementarity is explained. Direct detection experiments have revealed some possible indications of a dark matter signal, but the situation is quite confusing at the moment. Very recently, also indirect detection has entered a sensitivity region where some particle candidates could be detectable. Indeed, also here there are some (presently non‐conclusive) indications of possible dark matter signals, like an interesting structure at 130 GeV γ‐ray energy found in publicly available data from the Fermi‐LAT space detector. The future of the field will depend on whether WIMPs are indeed the dark matter, something that may realistically be probed in the next few years. If this exciting scenario turns out to be true, we can expect a host of other, complementary experiments in the coming decade. If it is not true, the time scale and methods for detection will be much more uncertain.

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Cosmology Favoring Extra Radiation and Sub-eV Mass Sterile Neutrinos as an Option

Cited by 222 publications

References 49 publications

Reactor sterile neutrinos, dark energy, and the age of the universe

Reactor sterile neutrinos, dark energy, and the age of the universe

Right-handed neutrinos as the dark radiation: Status and forecasts for the LHC

Dark matter evidence, particle physics candidates and detection methods

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