Related papers: Multiple Gamma Lines from Semi-Annihilation
We propose a new signature for weakly interacting massive particle (WIMP) dark matter, a spectral feature in the diffuse extragalactic gamma-ray radiation. This feature, a sudden drop of the gamma-ray intensity at an energy corresponding to…
A gamma line signal in cosmic-ray observation would be found when Higgs is produced at rest or almost rest by DM annihilation because of decay of 126 GeV Higgs into two gamma. This line signal gives a constraint on Higgs production cross…
High resolution simulations reveal that in the cold dark matter scenario the structures form hierarchically and a large number of substructures survive in the galactic halos. The substructures can be probed if they emit gamma rays via dark…
The origin of the cosmic gamma-ray background at 1-20 MeV remains a mystery. We show that gamma-ray emission accompanying annihilation of 20 MeV dark matter particles explains most of the observed signal. Our model satisfies all of the…
Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ~ 10 GeV - 1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which…
Motivated by the gamma-ray excess observed from the region surrounding the Galactic Center, we explore particle dark matter models that could potentially account for the spectrum and normalization of this signal. Taking a model-independent…
We study the capabilities of the Fermi-LAT instrument on board of the Fermi mission to constrain particle dark matter properties, as annihilation cross section, mass and branching ratio into dominant annihilation channels, with gamma-ray…
The recent results from the PAMELA, ATIC, FERMI and HESS experiments have focused attention on the possible existence of high energy cosmic ray e^+ e^- that may originate from dark matter (DM) annihilations or decays in the Milky Way. Here…
Existence of new gauge U(1) symmetry possessed by dark matter (DM) particles implies the existence of a new Coulomb-like interaction, which leads to Sommerfeld-Gamow-Sakharov enhancement of dark matter annihilation at low relative…
Dark matter can be boosted by various mechanisms, which may produce characteristic signals that are different from those of canonical dark matter. We show that the semi-annihilation $\chi\chi\to\bar{\chi}\nu$ produces signals that are…
We propose a model of multi-component dark matter with magnetic moments to explain the 130 GeV gamma-ray line hinted by the Fermi-LAT data. Specifically, we consider a U(1)_X dark sector which contains two vector-like fermions besides the…
The apparent excess of gamma rays in an extended region in the direction of the galactic center has a spatial distribution and amplitude that are suggestive of dark matter annihilations. If this excess is indeed due to dark matter…
We investigate the possibility of observing monochromatic neutrino lines originating from annihilation of dark matter. We analyse several astrophysical sources with overdensities of dark matter that can amplify the signal. As a case study,…
Although most proposed dark matter candidates are stable, in order for dark matter to be present today, the only requirement is that its lifetime is longer than the age of the Universe, t_U ~ 4 10^17 s. Moreover, the dark matter particle…
We consider regions of the parameter space of the Minimal Supersymmetric Standard Model (MSSM) with bino-like neutralino dark matter in which a large fraction of the total dark matter annihilation cross section in the present era arises…
Coy dark matter is an effective scheme in which a fermionic dark matter candidate interacts with the Standard Model fermions via a pseudoscalar mediator. This simple setup avoids the strong constraints posed by direct detection experiments…
Fermi-LAT has confirmed the excess in cosmic positron fraction observed by PAMELA, which could be explained by dark matter annihilating or decaying in the center of the galaxy. Most existing models postulate that the dark matter annihilates…
We discuss a simple theory for physics beyond the Standard Model where a Majorana dark matter is predicted from anomaly cancellation. We discuss in detail the minimal theory where the baryon number is a local symmetry spontaneously broken…
Over the past few years, there has been a hint of the $\gamma$-ray excess observed by the Fermi-LAT satellite borne telescope from the regions surrounding the Galactic Centre at an energy range $\sim 1$-$3$ GeV. The nature of this excess…
We study the prospects for detecting gamma-rays from Dark Matter (DM) annihilations in enhancements of the DM density (mini-spikes) around intermediate-mass black holes with masses in the range $10^2 \lsim M / \msun \lsim 10^6$. Focusing on…