With the extra energy gained from the cosmic rays, sub-GeV dark matter particles can produce visible recoil signals in the detector. We present a new result searching for the cosmic ray boosted dark matter (CRDM) with the PandaX-II full data. This work is motivated by the theoretical paper (PRL. 126 091804), which first pointed out that a sidereal diurnal modulation in signal rate and energy spectrum due to the Earth shielding is expected for low mass CRDM.
Specifically, detailed Jinping Mountain geometry is implemented with a realistic simulation on the scatterings between the DM and Earth nuclei. We reanalyzed the PandaX-II data with additional sidereal time information. Based on PandaX-II data, and thanks to the low background level and large exposure, our result excludes the dark matter-nucleon elastic scattering cross section between 10-31 cm2 and 10-28 cm2 for a dark matter masses from 0.1 MeV/c2 to 0.1 GeV/c2 ,which covers a large unexplored parameter space and provides new information beyond the cosmological and astrophysical probes.
This result is published on Phys. Rev. Lett. 128, 171801 (2022) as "Editors' Suggestion" paper. You may also find it here.