Related papers: Gamma rays and positrons from a decaying hidden ga…
We provide a scenario in which a hidden U(1) gauge boson constitutes dark matter of the Universe and decays into the standard-model particles through a kinetic mixing with an $U(1)_{B-L}$ gauge boson. Interestingly, our model can naturally…
We study a scenario that a hidden gaugino dark matter decays into the standard-model particles (and their supersymmetric partners) through a kinetic mixing with the gaugino of a U(1)B-L broken at a scale close to the grand unification…
Astrophysical and cosmological observations do not require the dark matter particles to be absolutely stable. If they are indeed unstable, their decay into positrons might occur at a sufficiently large rate to allow the indirect detection…
We show that the PAMELA anomaly in the positron fraction as well as the ATIC/PPB-BETS excesses in the e^- + e^+ flux are simultaneously explained in our scenario that a hidden U(1)H gauge boson constitutes dark matter of the Universe and…
A series of experiments measuring high-energy cosmic rays have recently reported strong indications for the existence of an excess of high-energy electrons and positrons. If interpreted in terms of the decay of dark matter particles, 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…
The Galactic positrons, as observed by their annihilation gamma-ray line at 0.511 MeV, are difficult to account for with astrophysical sources. It has been proposed that they are produced instead by dark matter annihilation or decay in the…
Stringent constraints from direct detection experiments and the Large Hadron Collider motivate us to consider models in which the dark matter does not directly couple to the Standard Model, but that instead annihilates into hidden sector…
High energy electrons and positrons from decaying dark matter can produce a significant flux of gamma rays by inverse Compton off low energy photons in the interstellar radiation field. This possibility is inevitably related with the dark…
Gravitino dark matter, together with thermal leptogenesis, implies an upper bound on the masses of superparticles. In the case of broken R-parity the constraints from primordial nucleosynthesis are naturally satisfied and decaying…
Fermi measurements of the high-latitude gamma-ray background strongly constrain a decaying-dark-matter origin for the 1--100 GeV Galactic positron anomaly measured with PAMELA. Inverse-Compton scattering of the microwave background by the…
We study a scenario that a U(1) hidden gaugino constitutes the dark matter in the Universe and decays into a lepton and slepton pair through a mixing with a U(1)B-L gaugino. We find that the dark-matter decay can account for the recent…
Recently, Dixon et al. have re-analyzed the EGRET data, finding a statistically significant diffuse $\gamma$-ray emission from the galactic halo. We show that this emission can naturally be explained within a previously-proposed model for…
In a strong magnetic field, B > 4x10^{12} G, gamma-rays emitted nearly along curved field lines adiabatically convert into bound electron-positron pairs (positronium atoms) rather that decaying into free pairs. This process may modify the…
The positron fraction in cosmic rays was found to be a steadily increasing in function of energy, above $\sim$ 10 GeV. This behaviour contradicts standard astrophysical mechanisms, in which positrons are secondary particles, produced in the…
Here we review our current knowledge on diffuse gamma-rays from galactic halos. Estimates of the relative contribution of the various emission processes at low and high latitudes are compared to the data over 6 decades in energy. The…
The gamma-ray excess observed from the Galactic Center can be interpreted as dark matter particles annihilating into Standard Model fermions with a cross section near that expected for a thermal relic. Although many particle physics models…
Dark Matter annihilation (DMA) may yield an excess of gamma rays and antimatter particles, like antiprotons and positrons, above the background from cosmic ray interactions. The excess of diffuse Galactic Gamma Rays from EGRET shows all the…
If interpreted in terms of decaying dark matter, the steep rise in the positron fraction of cosmic rays above 10 GeV, as observed by the PAMELA experiment, suggests an underlying production mechanism that favors leptonic channels. We…
A recent re-analysis of EGRET data by Dixon et al. has led to the discovery of a statistically significant diffuse $\gamma$-ray emission from the galactic halo. We show that this emission can naturally be accounted for within a…