Expected LHAASO sensitivity to decaying dark matter signatures from dwarf galaxies gamma-ray emission * * Supported by the National Key R & D Program of China (2016YFA0400200), the National Natural Science Foundation of China (U1738209, 11851303, 11835009, 11975072) and the National Program for Support of Top-Notch Young Professionals

Abstract

As a next-generation complex extensive air shower array with a large field of view, the large high altitude air shower observatory (LHAASO) is very sensitive to the very-high-energy gamma rays from ~300 GeV to 1 PeV and may thus serve as an important probe for the heavy dark matter (DM) particles. In this study, we make a forecast for the LHAASO sensitivities to the gamma-ray signatures resulting from DM decay in dwarf spheroidal satellite galaxies (dSphs) within the LHAASO field of view. Both individual and combined limits for 19 dSphs incorporating the uncertainties of the DM density profile are explored. Owing to the large effective area and strong capability of the photon-proton discrimination, we find that LHASSSO is sensitive to the signatures from decaying DM particles above TeV. The LHAASO sensitivity to the DM decay lifetime reaches s for several decay channels at the DM mass scale from 1 TeV to 100 TeV.