## PandaX: Particle and Astrophysical Xenon Experiments

PandaX is a staged experimental program that utilizes xenon detectors to search for elusive dark matter particles and understand neutrinos' fundamental properties. The PandaX collaboration has now entered into the multi-ton stage, PandaX-4T.

PandaX-II is a dark matter direct detection experiment equipped with a half-ton scale dual-phase time projection chamber (TPC), operated in CJPL between Oct. 2014 and June 2019. In 2016 and 2017, PandaX-II produced the world leading constraints to dark matter-nucleon interactions. See a list of scientific publications here.

With 6-ton of total Xenon and 4-ton sensitive target, PandaX-4T aims to improve the dark matter sensitivity by one order of magnitude in comparison to PandaX-II. PandaX-4T also plans to make sensitive searches on neutrinoless double beta decay of ${}^{136}Xe$ , and other signals from new physics. This project is expected to commence data taking in 2021.

PandaX-III searches for the possible neutrinoless double beta decay with 200 kg to one ton of 90% enriched ${}^{136}Xe$ in a high pressure gaseous Xenon TPC.

## News

• Prof. Xiangdong Ji of Shanghai Jiao Tong University and University of Maryland, spokesperson of the PandaX Collaboration, announced new results on the dark matter (DM) search from the PandaX-II experiment on Monday Aug. 7, during the TeV Particle Astrophysics 2017 Conference at Columbus, Ohio, the United States. No DM candidate was identified within the data from an exposure of 54 ton-day, the largest reported DM direct detection data set to date.

• The PandaX observatory uses xenon as target and detector to search for WIMP particles as well as neutrinoless double beta decay ($0\nu\beta\beta$) in ${}^{136}Xe$. At present, the PandaX-II experiment is in operation in CJPL-I. The future PandaX program will pursue the following three main directions:

• Xiangdong Ji, Spokesperson and Project Leader of the PandaX experiment located in the China Jin-Ping underground Laboratory (CJPL), announced the first dark matter search results from the PandaX-II 500 kg liquid xenon detector in the 2016 International Identification of Dark Matter conference at Sheffield, UK in the evening of July 21, 2016 (Beijing Time). He reported that no trace of dark matter was observed with an exposure of 33,000 kg·day of liquid xenon, providing the newest constraints on the existence of dark matter.