Abstract
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 500 GeV – 100 TeV gamma rays and cosmic rays. With its observations over 2/3 of the sky every day, the HAWC observatory is sensitive to a wide variety of astrophysical sources, including possible gamma rays from dark matter. Dark matter annihilation and decay in the Milky Way Galaxy should produce gamma-ray signals across many degrees on the sky. The HAWC instantaneous field-of-view of 2 sr enables observations of extended regions on the sky, such as those from dark matter in the Galactic halo. Here we show limits on the dark matter annihilation cross-section and decay lifetime from HAWC observations of the Galactic halo with 15 months of data. These are some of the most robust limits on TeV and PeV dark matter, largely insensitive to the dark matter morphology. These limits begin to constrain models in which PeV IceCube neutrinos are explained by dark matter which primarily decays into hadrons.
Highlights
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 500 GeV – 100 TeV gamma rays and cosmic rays
A number of models have been developed which explain the high-energy neutrino flux with DM [7, 22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43]. These models seek to explain the highest energy neutrinos observed by IceCube—the so-called High Energy Starting Events (HESE)— some deal with a putative excess in the lower energy Medium Energy Starting Events (MESE) [44], which has been discussed in the context of DM [45] and astrophysics [46, 47]
In order to correctly account for these abrupt unphysical discontinuities, we treat these as systematic errors, which we show as shaded bands around our limits
Summary
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 500 GeV – 100 TeV gamma rays and cosmic rays. We show limits on the dark matter annihilation cross-section and decay lifetime from HAWC observations of the Galactic halo with 15 months of data These are some of the most robust limits on TeV and PeV dark matter, largely insensitive to the dark matter morphology. These models seek to explain the highest energy neutrinos observed by IceCube—the so-called High Energy Starting Events (HESE)— some deal with a putative excess in the lower energy Medium Energy Starting Events (MESE) [44], which has been discussed in the context of DM [45] and astrophysics [46, 47] In these models the DM decays will generically produce photons which can be searched for in other experiments. In particular [7] considered the limits obtained with the Fermi-LAT, and demonstrated that models which seek to explain the majority of the IceCube flux appear to be in tension with the gamma-ray data. It extends to declinations of 8 degrees North (culminating at 11 degrees zenith for HAWC), so the analysis is not strongly dependent on the HAWC sensitivity at declinations with low sensitivity;
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
