We report the dark matter search results obtained using the full 132 ton·day exposure of the PandaX-II experiment, including all data from March 2016 to August 2018. No significant excess of events is identified above the expected background. Upper limits are set on the spin-independent dark matter-nucleon interactions. The lowest 90% confidence level exclusion on the spin-independent cross section is 2.2 × 10−46 cm2 at a WIMP mass of 30 GeV/c2.

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We present a systematic determination of the responses of PandaX-II, a dual phase xenon time projection chamber detector, to low energy recoils. The electron recoil (ER) and nuclear recoil (NR) responses are calibrated, respectively, with injected tritiated methane or 220Rn source, and with 241Am-Be neutron source, in an energy range from 1-25 keV (ER) and 4-80 keV (NR), under the two drift fields, 400 and 317 V/cm. An empirical model is used to fit the light yield and charge yield for both types of recoils. The best fit models can describe the calibration data significantly. The systematic uncertainties of the fitted models are obtained via statistical comparison to the data.

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We report a search for new physics signals using the low energy electron recoil events in the complete data set from PandaX-II, in light of the recent event excess reported by XENON1T. The data correspond to a total exposure of 100.7 ton⋅day with liquid xenon. With robust estimates of the dominant background spectra, we perform sensitive searches on solar axions and neutrinos with enhanced magnetic moment. It is found that the axion-electron coupling g Ae < 4.6 × 10–12 for an axion mass less than 0.1 keV/c 2 and the neutrino magnetic moment μν < 4.9 × 10–11 μ B at 90 % confidence level. The observed excess from XENON1T is within our experimental constraints.

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Level structures of neutron-rich 140 Xe nucleus have been reinvestigated by using a triple γ coincidence study from the spontaneous fission of 252 Cf. Several new levels and transitions are identified. The previously observed s = +1 octupole band structure is confirmed and expanded. Another set of the △I = 2 positive-and negative-parity bands connected by strong E1 transitions is proposed as the s = −1 octupole band structure. Thus, the s = ±1 doublet octupole bands are completed in 140 Xe. The experimental B(E1)/B(E2) branching ratios indicate that the octupole correlations in 140 Xe are weak. The other characteristics of the s = ±1 octupole bands have been discussed.

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