2020/04/30 by Ranjan Laha, Julian B. Muñoz, Tracy R. Slatyer · 3 citations
Physics and Astronomy · #astro-ph.CO #astro-ph.HE #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.101.123514
published as Phys. Rev. D 101, 123514 (2020) · 9 pages, 5 figures. Updated to match accepted version
arxiv created 2020/06/11 · arxiv updated 2020/07/01
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has yielded unprecedented measurements of the soft gamma-ray spectrum of our Galaxy. Here we use those measurements to set constraints on dark matter (DM) that decays or annihilates into photons with energies E≈ 0.02-2 MeV. First, we revisit the constraints on particle DM that decays or annihilates to photon pairs. In particular, for decaying DM, we find that previous limits were overstated by roughly an order of magnitude. Our new, conservative analysis finds that the DM lifetime must satisfy τ\gtrsim 5× 1026 \rm s× (mχ/\rm MeV)-1 for DM masses mχ=0.054-3.6 MeV. For MeV-scale DM that annihilates into photons INTEGRAL sets the strongest constraints to date. Second, we target ultralight primordial black holes (PBHs) through their Hawking radiation. This makes them appear as decaying DM with a photon spectrum peaking at E≈ 5.77/(8πG M\rm PBH), for a PBH of mass M\rm PBH. We use the INTEGRAL data to demonstrate that, at 95% C.L., PBHs with masses less than 1.2× 1017 g cannot comprise all of the DM, setting the tightest bound to date on ultralight PBHs.