Latest results on dark matter searches with H.E.S.S

Lucia Rinchiuso

doi:10.1051/epjconf/201920901023

Abstract

The nature of Dark Matter (DM) is one of the most debated questions of contemporary physics. Ground-based arrays of Cherenkov telescopes such as the High Energy Spectroscopic System (H.E.S.S.) search for DM signatures through the detection of Very-High-Energy (VHE, E > 100 GeV) gamma-rays. DM particles could selfannihilate in dense environments producing VHE γ-rays in the final states that could be eventually detected by H.E.S.S.. The H.E.S.S. observation strategy for DM search focuses towards the Galactic Centre (GC) region and nearby dwarf galaxy satellites of the Milky Way. The GC dataset provides the most stringent constraints on the DM annihilation cross section in the mass range 300 GeV - 70 TeV. Searches have been carried out towards classical and ultra-faint dwarf galaxies to test specific heavy DM models. The latest results towards the GC and dwarf galaxies are shown.

Highlights

The nature of Dark Matter (DM) is one of the most debated questions of contemporary physics
Imaging Atmospheric Cherenkov Telescopes (IACTs) can probe Dark Matter (DM) indirectly, i.e. through the detection of VHE γ-rays produced in the final state of self-annihilation of DM
If no significant excess is observed between the ON and OFF regions a Log-Likelihood Ratio Test Statistic (LLR TS) is performed to set 95% confidence level (C.L.) limits on σv for a fixed DM density profile and a specific annihilation channel

Summary

Dark matter annihilation

IACTs can probe Dark Matter (DM) indirectly, i.e. through the detection of VHE γ-rays produced in the final state of self-annihilation of DM. The expected γ-ray flux from DM annihilation writes: dφγ dE. We refer to the prompt photon annihilation channel as γ-line, and the annihilation channels with photons due to decay or hadronization of vector bosons, quarks and leptons in the final state as the continuum. The signal region, referred to as the ON region, is defined as a disk around the target, while the background is measured in signal-free or lower-signal regions in the same FoV (OFF region)

Likelihood analysis technique

The Galactic Center region

The dwarf galaxies satellites of the Milky Way

Findings

Prospects