Speaker
Description
Dark Matter (DM) particles may either self-annihilate or decay, producing detectable Standard Model (SM) particles, including gamma rays. These processes could lead to excesses in the gamma-ray energy spectra observed on Earth. In this work, we search for those excesses using the Fermi Large Area Telescope (Fermi-LAT) observations of the Milky Way in an energy range from 1 GeV to 1 TeV. We developed a maximum likelihood fit procedure with sliding energy windows to search for line-like features (smoking gun signals) as indirect signature of DM self-annihilation and decay processes that directly produce gamma rays. Our analysis is based on 185 months (15+ years) of Fermi-LAT data in which we selected five regions of the sky (RoIs) to optimize sensitivity for different theoretically motivated DM scenarios using a combined likelihood analysis technique. We also accounted for systematic uncertainties using the Galactic Plane as a control region.
Additionally, we investigate the presence of potential box-shaped spectral features in the gamma-ray spectra, which could result in a scenario in which DM annihilation or decay involves long-lived mediators that decay into final states of gamma rays detectable on Earth.
In both scenarios considered in this work, we do not find any significant detections, so we set more stringent upper limits for the DM velocity-averaged annihilation cross section compared to those quoted in literature.
| Collaboration(s) | Fermi-LAT collaboration |
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