Chinese scholars have made progress in the field of light dark matter detection

In recent years, the detection of light and dark matter has become a hot issue
in research.
In traditional theory, the elastic scattering of light dark matter and atomic nuclei is not enough to produce a large enough nuclear recoil to overcome the experimental energy threshold limit to be detected
.
If light dark matter is absorbed by electrons or nuclei, the mass can be converted into kinetic energy
of neutrinos and electrons or nuclei in the final state.
Therefore, light dark matter can generate a large enough electron or nuclear recoil signal through this process to be detected experimentally, opening a window
for the detection of light dark matter.

Relying on PandaX-4T, a new generation of multi-ton liquid xenon detection experiment (Figure 1), independently developed in China's underground laboratory in Jinping, the team systematically studied the energy response of the nuclear recoil signal generated by the absorption of dark matter by atomic nuclei, and made strict restrictions on the cross-section of light dark matter with a mass of tens of MeV absorbed by atomic nuclei (Figure 2).
For a new Z' boson that delivers this new type of absorption, PandaX-4T is more limited than the results of
collider experiments.
For the signal of light dark matter being absorbed by electrons, the team gave the latest limit on the absorption of electrons by vector or axial vector action of light dark matter with a mass of tens of keV by scanning the electron recoil data (Figure 3), which exceeds the limit of astronomical observations; This measurement is consistent
with the latest results published by XENONnT, an international experiment of the same kind.

This study explores the search for light dark matter by mining new signal features from massive experimental data, and expands the physical potential of
direct dark matter detection.