Dark Matter Results from First 98.7 Days of Data from the PandaX-II Experiment

Abstract

We report the WIMP dark matter search results using the first physics-run data of the PandaX-II 500 kg liquid xenon dual-phase time-projection chamber, operating at the China JinPing underground Laboratory. No dark matter candidate is identified above background. In combination with the data set during the commissioning run, with a total exposure of 3.3×10 4 kg-day, the most stringent limit to the spin-independent interaction between the ordinary and WIMP dark matter is set for a range of dark matter mass between 5 and 1000 GeV/c 2 . The best upper limit on the scattering cross section is found 2.5 × 10 −46 cm 2 for the WIMP mass 40 GeV/c 2 at 90% confidence level.Weakly interacting massive particles, WIMPs in short, are a class of hypothetical particles that came into existence shortly after the Big Bang. The WIMPs could naturally explain the astronomical and cosmological evidences of dark matter in the Universe. The weak interactions between WIMPs and ordinary matter could lead to the recoils of atomic nuclei that produce detectable signals in deep-underground direct detection experiments. Over the past decade, the dual-phase xenon time-projection chambers (TPC) emerged as a powerful technology for WIMP searches both in scaling up the target mass, as well as in improving background rejection [1][2][3]. LUX, a dark matter search experiment with a 250 kg liquid xenon target, has recently reported the best limit of 6×10 −46 cm 2 on the WIMP-nucleon scattering cross section [4] The PandaX-II experiment, a half-ton scale dual-phase xenon experiment at the China JinPing underground Laboratory (CJPL), has recently reported the dark matter search results from its commissioning run (Run 8,19.1 live days) with a 5845 kg-day exposure [5]. The data were contaminated with significant 85 Kr background. After a krypton distillation campaign in early 2016, PandaX-II commenced physics data taking in March 2016. In this paper, we report the combined WIMP search results using the data from the first physics run from March 9 to June 30, 2016 (Run 9, 79.6 live days) and Run 8, with a total of 3.3×10 4 kg-day exposure, the largest reported WIMP data set among dual-phase xenon detectors in the world to date.The PandaX-II detector has been described in detail in Ref. [5]. The liquid xenon target consists of a cylindrical TPC with dodecagonal cross section (opposite-side distance 646 mm), confined by the polytetrafluoroethylene (PTFE) reflective wall, and a vertical drift distance of 600 mm defined by the cathode mesh and gate grid located at the bottom and top. For each physical event, the prompt scintillation photons (S1) and the delayed electroluminescence photons (S2) from the ionized electrons are collected by two arrays of 55 Hamamatsu R11410-arXiv:1607.07400v3 [hep-ex] Hamamatsu R8520-406 1-inch PMTs serving as an active veto. The γ background, which produces electron recoil (ER) events, can be distinguished from the dark matter nuclear recoil (NR) using the S2-to-S1 ratio. During the data taking period in Run 9, a few diffe...

Multicomponent Dark Matter from gauge symmetry

“…Indeed, by crossing symmetry arguments, there is a relation between the DM pair annihilation cross-section at freeze-out, responsible for the relic density, and the processes potentially responsible for detection signals, such as scattering on nuclei, probed by Direct Detection experiments, or production at colliders. Null results of the latter then rule out large portions of the parameter space favoured by the thermal WIMP paradigm [15][16][17]. If the s-wave DM annihilation cross section remains substantial at present times, the model can also be probed by Indirect Detection experiments.…”

“…The reason for this are the particular h 1 , h 2 couplings to χ, which are inherent in our model, 17) as well as the h 1 , h 2 couplings to SM matter.…”

Search for dark matter in association with a Higgs boson decaying to two photons at s=13 TeV with the ATLAS detector

“…Limits are shown at 90% C.L. For comparison, results from direct detection experiments (LUX [67], PandaX-II [68], XENON [69], superCDMS [70], and CRESST-II [71]) are also shown. The comparison is model dependent and solely valid in the context of this model.…”

“…[GeV] The results from this analysis, in which the region inside the contour is excluded, are compared with limits from the LUX [67], PandaX-II [68], XENON [69], superCDMS [70], and CRESST-II [71] experiments. The comparison is model dependent and solely valid in the context of this model, assuming Dirac fermion DM, mixing angle sin θ ¼ 0.3, and the coupling values g q ¼ 1=3 and g χ ¼ 1.…”

Study of dark matter physics in non-universal gaugino mass scenario

“…are given by the XENON100 [61][62][63], LUX [64,65], PANDAX-II [66,67] and PICO [68,69]. The XENON1T [70] and LZ [71] will cover wider range in near future.…”