## PandaX: Particle and Astrophysical Xenon Experiments

PandaX is designed to build and operate a ton-scale liquid xenon experiment to search elusive dark matter particles and neutrinoless double beta decay.

PandaX-II is a dark matter direct detection experiment equipped with a half-ton scale dual-phase time projection chamber (TPC). The PandaX-II experiment started since Oct 2014 with the detector installation at CJPL, followed by about one year of engineering runs and test. The commissiong run started on Nov 22, 2015.

Combining the data from the comissioning run and the first physics run, PandaX-II obtained the most stringent upper limits on the SI WIMP-nucleon cross sectiones for WIMPs with masses between 5 and 1000 GeV.

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

Combining the data from the comissioning run and the first physics run, PandaX-II obtained the most stringent upper limits on the SI WIMP-nucleon cross sectiones for WIMPs with masses between 5 and 1000 GeV.

6 tons total, 4 tons sensitive target to push the DM sensitivity down to $6\times10^{-48} cm^{2}$.

## News

• New results on the detection of axions and galaxy axion-like particles(ALPs) with 80 day of PandaX-II data were published online in Physical Review Letters on Nov 1, 2017 (on the same issue with another PandaX-II paper on 54 ton-day WIMP search results).

• Recent result from PandaX-II was published on Physical Review Letter (Phys. Rev. Lett. 119, 181302, "Editor's Suggestion") on October 30, 2017, back-to-back with the first result from XENON1T experiment. The papers are highlighted by a Physics "Viewpoint" commentary by Dan Hooper from FNAL and Univ. of Chicago, commenting that “...

• The PandaX-II collaboration released the official WIMP search results using 54 ton-day exposure on Aug. 23, 2017. No excess events were found above the expected background. The most stringent upper limit on spin-independent WIMP-nucleon cross section was set for a WIMP mass greater than $100 GeV/c^{2}$, with the lowest exclusion at $8.6\times10^{-47} cm^{2}$ at $40 GeV/c^{2}$. The result reported here is more conservative than the preliminary result shown during the TeVPA2017 conference, due to the adoption of updated photon/electron detection efficiencies.

• 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:

## Events

• Tuesday, June 25, 2019 - 08:00
YuGang Bao Library

Following the activity on Exotic Hadrons initiated last year at T. D. Lee Institute in Shanghai, we are glad to announce the Workshop

Exotic Hadrons: Theory and Experiment at Lepton and Hadron Colliders

to be held at the T.D. Lee Institute, located in Shanghai Jiao Tong University, June 25-27, 2019.

• Sunday, April 28, 2019 - 18:00
T. D. Lee Library

GEANT4 is a powerful toolkit for detector simulations which is widely used in many applications of high energy physics, space and radiation, medical and so on.

• Wednesday, January 9, 2019 - 09:00
T. D. Lee Library