Search results for "Scalar field dark matter"
showing 10 items of 26 documents
Future CMB cosmological constraints in a dark coupled universe
2010
Cosmic microwave background satellite missions as the ongoing Planck experiment are expected to provide the strongest constraints on a wide set of cosmological parameters. Those constraints, however, could be weakened when the assumption of a cosmological constant as the dark energy component is removed. Here we show that it will indeed be the case when there exists a coupling among the dark energy and the dark matter fluids. In particular, the expected errors on key parameters as the cold dark matter density and the angular diameter distance at decoupling are significantly larger when a dark coupling is introduced. We show that it will be the case also for future satellite missions as EPIC…
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.
Uncertainty on w from large-scale structure
2012
We find that if we live at the center of an inhomogeneity with total density contrast of roughly 0.1, dark energy is not a cosmological constant at 95% confidence level. Observational constraints on the equation of state of dark energy, w, depend strongly on the local matter density around the observer. We model the local inhomogeneity with an exact spherically symmetric solution which features a pressureless matter component and a dark-energy fluid with constant equation of state and negligible sound speed, that reaches a homogeneous solution at finite radius. We fit this model to observations of the local expansion rate, distant supernovae and the cosmic microwave background. We conclude …
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.
Predictive discrete dark matter model and neutrino oscillations
2012
Dark Matter stability can be achieved through a partial breaking of a flavor symmetry. In this framework we propose a type-II seesaw model where left-handed matter transforms nontrivially under the flavor group Delta(54), providing correlations between neutrino oscillation parameters, consistent with the recent Daya-Bay and RENO reactor angle measurements, as well as lower bounds for neutrinoless double beta decay. The dark matter phenomenology is provided by a Higgs-portal.
Systematic uncertainties from halo asphericity in dark matter searches
2015
Although commonly assumed to be spherical, dark matter halos are predicted to be non-spherical by N-body simulations and their asphericity has a potential impact on the systematic uncertainties in dark matter searches. The evaluation of these uncertainties is the main aim of this work, where we study the impact of aspherical dark matter density distributions in Milky-Way-like halos on direct and indirect searches. Using data from the large N-body cosmological simulation Bolshoi, we perform a statistical analysis and quantify the systematic uncertainties on the determination of local dark matter density and the so-called $J$ factors for dark matter annihilations and decays from the galactic …
Direct and indirect singlet scalar dark matter detection in the lepton-specific two-Higgs-doublet model
2011
A recent study of gamma-ray data from the Galactic Center motivates the investigation of light (~7-10 GeV) particle dark matter models featuring tau lepton pairs as dominant annihilation final state. The Lepton-Specific two-Higgs-doublet Model (2HDM-L) provides a natural framework where light, singlet scalar dark matter can pair-annihilate dominantly into tau leptons. We calculate the nucleon-dark matter cross section for singlet scalar dark matter within the 2HDM-L framework, and compare with recent results from direct detection experiments. We study how direct dark matter searches can be used to constrain the dark matter interpretation of gamma ray observations, for different dominant ann…
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…
Fuzzy Dark Matter and Non-Standard Neutrino Interactions
2018
We discuss novel ways in which neutrino oscillation experiments can probe dark matter. In particular, we focus on interactions between neutrinos and ultra-light ("fuzzy") dark matter particles with masses of order $10^{-22}$ eV. It has been shown previously that such dark matter candidates are phenomenologically successful and might help ameliorate the tension between predicted and observed small scale structures in the Universe. We argue that coherent forward scattering of neutrinos on fuzzy dark matter particles can significantly alter neutrino oscillation probabilities. These effects could be observable in current and future experiments. We set new limits on fuzzy dark matter interacting…