Searching for secluded dark matter with H.E.S.S., Fermi-LAT, and Planck

Abstract

Short-lived mediators are often used to describe dark matter interactions with Standard Model particles. When the dark matter mass is heavier than the mass of the mediator, it may self-annihilate into short-lived mediators, and in some cases this might be the dominant annihilation channel. This scenario is known as secluded dark matter. We use Fermi-LAT observations of dwarf spheroidal galaxies, H.E.S.S. data from the Galactic center, and Planck measurements of the Cosmic Microwave Background to constrain secluded dark matter. We explore the interplay between these experiments and we assess the impact of the mediator mass on our bounds, an often overlooked yet very important point. In particular, we exclude pair -annihilation cross-sections greater or on the order of σv ∼ 4 × 10 −27 cm 3 /s for dark matter masses around 10 GeV and greater or on the order of σv ∼ ×10 −25 cm 3 /s for dark matter masses around a TeV. Our findings supersede previous constraints which use Fermi-LAT data, and constitute the first limits on secluded dark sectors using the H.E.S.S. telescope. We also show that one can fit TeV gamma-ray observations from H.E.S.S. with secluded dark matter annihilations, with the mediator mass impacting the best-fit dark matter particle mass. Our findings indicate that any assessment of secluded dark sectors in the context of indirect detection significantly depends on the choice of the mediator mass. 1 4πσv 4.4 × 10 −25 cm 3 /s Planck CMB 4b, M DM = 100 GeV CMB 4b, M DM = 1 TeV M DM M V → σv 2.5 × 10 −25 cm 3 /s M DM M V → σv 3 × 10 −24 cm 3 /s M DM ∼ M V → σv 2.5 × 10 −25 cm 3 /s M DM ∼ M V → σv 2.5 × 10 −24 cm 3 /s CMB 4e, M DM = 100 GeV CMB 4e, M DM = 1 TeV M DM M V → σv 10 −25 cm 3 /s M DM M V → σv 10 −24 cm 3 /s M DM ∼ M V → σv 1.5 × 10 −25 cm 3 /s M DM ∼ M V → σv 1.5 × 10 −24 cm 3 /s

Explaining the DAMPE data with scalar dark matter and gauged $$U(1)_{L_e-L_\mu }$$ U ( 1 ) L e

“…data on the annihilation χχ → V V → 2(e + e − ) [52,53], the Fermi-LAT data in the direction of the dwarf spheroidal galaxies [54], the Planck CMB data which is sensitive to energy injection to the CMB from DM annihilations [55,56], and the IceCube data on DM annihilation into neutrinos [57]. It also survives the upper bounds from XENON-10 and XENON-100 experiments on the DM scattering off electron [58].…”

GeV-scale thermal WIMPs: Not even slightly ruled out

“…Other than CTA [157], current generation telescopes, H.E.S.S. [86,87,89,158], VERITAS (Very Energetic Radiation Imaging Telescope Array System) [159,160], MAGIC (Major Atmospheric Gamma Imaging Cherenkov Telescopes) [161][162][163], HAWC (High-Altitude Water Cherenkov Observatory) [164][165][166][167][168], DAMPE (Dark Matter Particle Explorer mission) [169], and in future LHAASO (Large High Altitude Air Shower Observatory) [170,171], will also aid eventually closing up to the unitarity limit at ∼100 TeV.…”

Scalar dark matter explanation of the DAMPE data in the minimal left-right symmetric model

“…[65,78] for a detailed discussion), such as the H.E.S.S. data on the annihilation χχ → S Ã S → 4e [97,113], the Fermi-LAT data in the direction of the dwarf spheroidal galaxies [114], the Planck cosmic microwave background (CMB) data which is sensitive to energy injection in the CMB from DM annihilations [115,116], and the IceCube data on DM annihilation into neutrinos [117]. Dark matter in our scenario also survives the upper bounds from the XENON-10 and XENON-100 experiments on DM-electron scattering [118].…”