The Large High Altitude Air Shower Observatory (LHAASO) scientists have presented 1.5 years of observational data. They have calculated new limits on the lifetime of heavy dark matter particles with masses ranging from 105 to 109 giga-electron volts.
The paper is titled as “Constraints on heavy decaying dark matter from 570 days of LHAASO observations”. It has been published recently in Physics Review Letters.
According to the Milky Way’s gravitational model, the galactic center has a very high density of dark matter. The gamma rays produced by the decay of this dark matter will radiate from the galactic center to the surroundings for hundreds or even thousands of light-years. However, the presence of other background radiation has long complicated the observation of ultra-high-energy gamma rays produced by heavy dark matter.
LHAASO has the very unique potential to observe gamma rays decaying from heavy dark matter. Because it has an unprecedentedly high detection sensitivity to ultra-high-energy gamma rays. LHAASO can eliminate background events by nearly six orders of magnitude above 100 TeV. It reduces background interference and improving gamma ray capture.
Scientists measured the intensity of ultra-high-energy gamma rays beyond the galactic plane using data from the LHAASO KM2A subarray. It placed some of the strongest limits on the lifetime of heavy dark matter so far. The upper limit is nearly ten times greater than previous results. According to this research, PeV mass dark matter has a lifetime of at least billion trillion years (1021 years).
LHAASO’s gamma-ray observations are highly complementary to other experiments looking for dark matter. This limit will be increased as the LHAASO full array continues to operate reliably and accumulates data.