Related papers: Multi-component dark matter and Galactic 511 keV $…
Over the past few decades, an anomalous 511 keV gamma-ray line has been observed from the centre of the Milky Way. Dark matter (DM) in the form of light weakly interacting massive particles (WIMPs) annihilating into electron-positron pairs…
About one year ago, it was speculated that decaying or annihilating Light Dark Matter (LDM) particles could explain the flux and extension of the 511 keV line emission in the galactic centre. Here we present a thorough comparison between…
The origin of both the diffuse high-latitude MeV gamma-ray emission and the 511 keV line flux from the Galactic bulge are uncertain. Previous studies have invoked dark matter physics to independently explain these observations, though as…
We study the morphology of the 511 keV signal that could be produced by exciting dark matter (XDM) in the Milky Way. In this model, collisions between dark matter particles excite the dark matter to a state that can then decay back to the…
We explore dark matter mechanisms that can simultaneously explain the galactic 511 keV gamma rays observed by INTEGRAL/SPI, the DAMA/LIBRA annual modulation, and the excess of low-recoil dark matter candidates observed by CoGeNT. It…
We explore the $511$~keV emission associated to sub-GeV dark matter (DM) particles that can produce electron-positron pairs and form positronium after thermalizing. We use $\sim16$~yr of SPI data from INTEGRAL to constrain DM properties,…
Both the robust INTEGRAL 511 keV gamma-ray line and the recent tentative hint of the 135 GeV gamma-ray line from Fermi-LAT have similar signal morphologies, and may be produced from the same dark matter annihilation. Motivated by this…
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 galactic 511 keV gamma-ray line has been observed since 1970's, and was identified as the result of electron-positron annihilation, but the origin of such positrons is still not clear. Apart from the astrophysical explanations, the…
We propose a novel framework where MeV-scale Dirac Dark Matter annihilates into axion-like particles, providing a natural explanation for the 511 keV gamma-ray line observed in the Galactic Center. The relic abundance is determined by…
The observed galactic 511 keV line has been interpreted in a number of papers as a possible signal of dark matter annihilation within the galactic bulge. If this is the case then we should expect a similar spectral feature associated with…
The document discusses a proposed extension to the Standard Model that aims to explain the presence of neutrino masses and the existence of dark matter. The model includes two potential candidates for dark matter, a vector WIMP and a…
We consider possible mechanisms via which electroweak scale WIMPs \chi^0 could provide the source of the INTEGRAL/SPI 511 keV photon flux from the galactic centre. We consider scenarios where the WIMP spectrum contains near-degeneracies,…
Multi-component dark matter scenarios constitute natural extensions of standard single-component setups and offer attractive new dynamics that could be adopted to solve various puzzles of dark matter. In this work we present and illustrate…
We present a possible explanation of the recently observed 511 keV $\gamma$-ray anomaly with a new ``millicharged'' fermion. The new fermion is light (${\cal O}({\rm MeV})$) but has never been observed by any collider experiments mainly…
The high positron production rate required to explain the flux of 511 keV gamma rays from the galactic center has inspired many models in which dark matter creates positrons. These models include the annihilation of light dark matter and…
An emission line with energy of $E\sim 3.5$ keV has been observed in galaxy clusters by two experiments. The emission line is consistent with the decay of a dark matter particle with a mass of $\sim 7$ keV. In this work we discuss the…
Recent results from the PAMELA experiment indicate an excess in the positron spectrum above 10 GeV, but anti-proton data are consistent with the expected astrophysical backgrounds. We propose a scenario that reproduces these features. Dark…
We consider an extension of the Standard Model that explains the neutrino masses and has a rich dark matter phenomenology. The model has two dark matter candidates, a vector WIMP and a fermion FIMP, and the sum of their relic densities…
Recent observations of the 511 keV positron-electron annihilation line in the Galactic centre region by the INTEGRAL/SPI spectrometer have stirred up new speculations about the origin of the large corresponding positron injection rate.…