PandaX

PandaX is a scientific collaboration that operates xenon-based direct-detection experiments aimed at searching for dark matter at the China Jinping Underground Laboratory (CJPL) in Sichuan Province, China. The program uses dual-phase liquid xenon time projection chambers to detect rare interactions between dark matter particles and atomic nuclei, exploiting low background environments provided by deep underground operation.

The PandaX program has progressed through a staged series of detectors. PandaX-I was a smaller, early detector with about 120 kilograms of liquid xenon. PandaX-II followed with a larger active target of around 580 kilograms, improving sensitivity to potential dark matter signals. PandaX-4T represents a four-tonne-class instrument designed to achieve substantially greater sensitivity and to expand the physics reach of the experiment.

In terms of science, PandaX experiments search for nuclear recoils from WIMP (weakly interacting massive particle) dark matter scattering. The collaboration has produced competitive limits on the spin-independent WIMP-nucleon cross section, contributing to the global effort to constrain or detect dark matter interactions. The results are complementary to those from other leading xenon-based detectors and help map out the parameter space for dark matter models across a broad range of masses.

CJPL provides a deep underground environment with substantial rock overburden to reduce cosmic-ray backgrounds, which is crucial for rare-event searches. The PandaX collaboration includes institutions from China and international partners, and data collection continues to improve limits and explore additional physics channels within the xenon detector program.