Related papers: Dark Matter Casts Light on the Early Universe
The $\Lambda$-CDM model of cosmology has done much to clarify our picture of the early universe. However, there are still some questions that $\Lambda$-CDM does not necessarily answer; questions such as what is the fundamental nature of…
The primordial abundances of the light nuclides produced by Big Bang Nucleosynthesis (BBN) during the first 20 minutes in the evolution of the Universe are sensitive to the universal density of baryons and to the expansion rate of the early…
Standard lore states that there is tension between the need to accommodate the relic density of a weakly interacting massive particle and direct searches for dark matter. However, the estimation of the relic density rests on an…
We perform calculations of dark photon production and decay in the early universe for ranges of dark photon masses and vacuum coupling with standard model photons. Simultaneously and self-consistently with dark photon production and decay,…
We consider a cosmological model in which a fraction $f$ of the Dark Matter (DM) is allowed to decay in an invisible relativistic component, and compute the resulting constraints on both the decay width (or inverse lifetime) $\Gamma$ and…
After the observation in 2012 of a new scalar particle closely resembling the Higgs boson of the Standard Model of particle physics, there is a general consensus that there must be Physics Beyond the Standard Model, with present experiments…
We consider the history of the universe from a possible big bang or a bounce into a late period of a unified interacting dark energy - dark matter model. The model is based on the Two Measures Theories (T.M.T.) which introduces a metric…
The lightest supersymmetric particle, most likely the neutralino, might account for a large fraction of dark matter in the Universe. We show that the primordial spectrum of density fluctuations in neutralino cold dark matter (CDM) has a…
If supersymmetry exists at any scale, regardless of whether it is restored around the weak scale, it may be a good symmetry of the dark sector, enforcing a degeneracy between its lowest lying fermions and bosons. We explore the implications…
A fast transition between a standard matter-like era and a late $\Lambda$CDM-like epoch generated by a single Unified Dark Matter component can explain the observed acceleration of the Universe. UDM models with a fast transition should be…
In the very last years, cosmological models where the properties of the dark components of the Universe - dark matter and dark energy - are accounted for by a single "dark fluid" have drawn increasing attention and interest. Amongst many…
We explore the observational adequacy of a class of Unified Dark Energy/Matter (UDE/M) models with a fast transition. Our constraints are set using a combination of geometric probes, some low redshift ones, and some high redshift ones (CMB…
Primordial nucleosynthesis provides a probe of the universal abundance of baryons when the universe was only a few minutes old. Recent observations of anisotropy in the cosmic microwave background (CMB) probe the baryon abundance when the…
The cold dark matter (CDM) model of structure formation, normalized on large scales, leads to excessive pairwise velocity dispersions on small scales. In an attempt to circumvent this problem, we study three scenarios (all with $\Omega=1$)…
We show that a nonstandard cosmological history with a period of early matter domination driven by a sub-TeV visible-sector particle can arise rather naturally. This scenario involves a long-lived standard model singlet that acquires a…
We present a new dark matter model BDM which is an hybrid between hot dark matter HDM and cold dark matter CDM, in which the BDM particles behave as HDM above the energy scale E_c and as CDM below this scale. Evolution of structure…
The direct detection rate for supersymmetric cold dark matter (CDM) particles is calculated for a number of suitable nuclear targets. Both the coherent and spin contributions are considered. By considering representative phenomenologically…
Dark Matter (DM) annihilation and decay during the Dark Ages can affect the cosmic ionization history and leave imprints in the Cosmic Microwave Background (CMB) anisotropy spectra. CMB polarization anisotropy can be sensitive to such…
We do a comprehensive study of the Bayesian evidences for a large number of dark energy models using a combination of latest cosmological data from SNIa, CMB, BAO, Strong lensing time delay, Growth measurements, measurements of Hubble…
As the early universe expands and cools the rates of the weak interactions that keep neutrinos in thermal equilibrium with the matter and the related rates of the reactions that inter-convert neutrons and protons decrease. Eventually, these…