Related papers: The Case for Dark Radiation
We consider the generic possibility that the Universe's energy budget includes some form of relativistic or semi-relativistic dark radiation (DR) with non-gravitational interactions with Standard Model (SM) particles. Such dark radiation…
Recent observations constrain the amount of Dark Radiation ($\Delta N_{\rm eff}$) and may even hint towards a non-zero value of $\Delta N_{\rm eff}$. It is by now well-known that this puts stringent constraints on the sequestered Large…
We consider the inference of the cosmic radiation density, traditionally parameterised as the effective number of neutrino species N_eff, from precision cosmological data. Paying particular attention to systematic effects, notably…
We present joint constraints on the number of effective neutrino species N_eff and the sum of neutrino masses M_nu, based on a technique which exploits the full information contained in the one-dimensional Lyman-Alpha forest flux power…
Neutrinos heavier than $M_Z/2\sim 45$ GeV are not excluded by particle physics data. Stable neutrinos heavier than this might contribute to the cosmic gamma ray background through annihilation in distant galaxies as well as to the dark…
Although Planck data supports the standard \Lambda CDM model, it still allows for the presence of Dark Radiation corresponding up to about half an extra standard neutrino species. We propose a scenario for obtaining a fractional "effective…
Some particle candidates for dark matter are reviewed in the light of recent experimental and theoretical developments. Models for massive neutrinos are discussed in the light of the recent atmospheric-neutrino data, and used to motivate…
Tantalizing cosmological and terrestrial evidence suggests the number of light neutrinos may be greater than 3, motivating a careful re-examination of cosmological bounds on extra light species. Big Bang Nucleosynthesis constrains the…
The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational…
Cosmological data have provided new constraints on the number of neutrino species and the neutrino mass. However these constraints depend on assumptions related to the underlying cosmology. Since a correlation is expected between the number…
The observed excess radio background has remained a puzzle for over a decade. A recent new physics solution involves dark matter that decays into dark photons in the presence of a thermal dark photon background. The produced non-thermal…
The excess radio background detected by ARCADE 2 represents a puzzle within the standard cosmological model. There is no clear viable astrophysical solution, and therefore, it might indicate the presence of new physics. Radiative decays of…
We present here up-to-date neutrino mass limits exploiting the most recent cosmological data sets. By making use of the Cosmic Microwave Background temperature fluctuation and polarization measurements, Supernovae Ia luminosity distances,…
We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could…
Cosmological measurements of the radiation density in the early universe can be used as a sensitive probe of physics beyond the standard model. Observations of primordial light element abundances have long been used to place non-trivial…
The dark matter scattering with atomic bound electrons is a crucial avenue for exploring the sub-GeV mass range. If not handled properly, even negative values can arise in the scattering matrix element squared or equivalently the…
Biswas et al. found that the thermal relic density of a dark matter particle freezing out while the universe's energy density is dominated by a non-standard extra component $\phi$, whose energy density redshifts faster than radiation, can…
Results of calculations of distribution and motion of dark matter are presented. Considering neutrino as one of the components of dark matter and taking into account peculiar features of the interactions of slow neutrinos with matter, allow…
Generalized fluid equations, using sound speed $c_{\rm eff}^2$ and viscosity $c_{\rm vis}^2$ as effective parameters, provide a convenient phenomenological formalism for testing the relic neutrino "null hypothesis," i.e. that that neutrinos…
Neutrino astronomy offers the possibility to perform extra-galactic observations well beyond the photon absorption cutoff above 50 TeV. Based on observations of cosmic rays, we already know that astrophysical sources produce particles with…