Search results for "Warm dark matter"
showing 10 items of 15 documents
Determining the dark matter mass with DeepCore
2013
Cosmological and astrophysical observations provide increasing evidence of the existence of dark matter in our Universe. Dark matter particles with a mass above a few GeV can be captured by the Sun, accumulate in the core, annihilate, and produce high energy neutrinos either directly or by subsequent decays of Standard Model particles. We investigate the prospects for indirect dark matter detection in the IceCube/DeepCore neutrino telescope and its capabilities to determine the dark matter mass.
Planck-scale effects on WIMP dark matter
2014
There exists a widely known conjecture that gravitational effects violate global symmetries. We study the effect of global-symmetry violating higher-dimension operators induced by Planck-scale physics on the properties of WIMP dark matter. Using an effective description, we show that the lifetime of the WIMP dark matter candidate can satisfy cosmological bounds under reasonable assumptions regarding the strength of the dimension-five operators. On the other hand, the indirect WIMP dark matter detection signal is significantly enhanced due to new decay channels.
Limits on the parameters of the equation of state for interacting dark energy
2010
Under the assumption that cold dark matter and dark energy interact with each other through a small coupling term, $Q$, we constrain the parameter space of the equation of state $w$ of those dark energy fields whose variation of the field since last scattering do not exceed Planck's mass. We use three parameterizations of $w$ and two different expressions for $Q$. Our work extends previous ones.
Warm dark matter and the ionization history of the Universe
2017
In warm dark matter scenarios structure formation is suppressed on small scales with respect to the cold dark matter case, reducing the number of low-mass halos and the fraction of ionized gas at high redshifts and thus, delaying reionization. This has an impact on the ionization history of the Universe and measurements of the optical depth to reionization, of the evolution of the global fraction of ionized gas and of the thermal history of the intergalactic medium, can be used to set constraints on the mass of the dark matter particle. However, the suppression of the fraction of ionized medium in these scenarios can be partly compensated by varying other parameters, as the ionization effic…
Cores and Cusps in Warm Dark Matter Halos
2011
The apparent presence of large core radii in Low Surface Brightness galaxies has been claimed as evidence in favor of warm dark matter. Here we show that WDM halos do not have cores that are large fractions of the halo size: typically, r_core/r_200 < 0.001. This suggests an astrophysical origin for the large cores observed in these galaxies, as has been argued by other authors.
Constraints on light asymmetric dark matter from solar neutrinos
2010
We study the effect of dark matter (DM) particles in the Sun, focusing in particular on the possible reduction of the solar neutrinos flux due to the energy carried away by DM particles from the innermost regions of the Sun, and to the consequent reduction of the temperature of the solar core. In the very low-mass range between 4 and 10 GeV, recently advocated to explain the findings of the DAMA and CoGent experiments, the effects on neutrino fluxes are detectable only for DM models with very small, or vanishing, self-annihilation cross section, such as the so-called asymmetric DM models, and we study the combination of DM masses and Spin Dependent cross sections which can be excluded with …
New Atomic Methods for Dark Matter Detection
2015
We calculate the parity and time-reversal violating effects that are induced in atoms, nuclei, and molecules by their interaction with various background cosmic fields, such as axion dark matter or dark energy.
SINGLET NEUTRINOS AS HOT DARK MATTER
1993
A model is presented that generates mass and magnetic moment matrices for singlet neutrinos radiatively at one-loop level. It allows the singlet neutrinos to account for the hot dark matter and the anomalous ionization of interstellar hydrogen.
Cold positrons from decaying dark matter
2012
Many models of dark matter contain more than one new particle beyond those in the Standard Model. Often heavier particles decay into the lightest dark matter particle as the Universe evolves. Here we explore the possibilities that arise if one of the products in a (Heavy Particle) $\rightarrow$ (Dark Matter) decay is a positron, and the lifetime is shorter than the age of the Universe. The positrons cool down by scattering off the cosmic microwave background and eventually annihilate when they fall into Galactic potential wells. The resulting 511 keV flux not only places constraints on this class of models but might even be consistent with that observed by the INTEGRAL satellite.
Reconciling dark matter and solar neutrinos
1993
Abstract We present a simple model for neutrino dark matter in which neutrino masses arise radiatively and the solar neutrino data are explained via the MSW effect. The dark matter scale arises at the one-loop level with the MSW scale arises only in two loops. The model is compatible with all observational facts and allows observable ν e ν τ or ν μ ν τ oscillation rates in the laboratory if the limits from primordial big bang nucleosynthesis (BBN) are taken conservatively. In addition, it can be probed by searching for muon number violating processes such as μ → e + γ , and μ →3 e . These rates can well lie within the sensitivities of present experiments. Finally, if we ignore BBN limits we…