Author
Xun Chen
Other affiliations: Peking University
Bio: Xun Chen is an academic researcher from Shanghai Jiao Tong University. The author has contributed to research in topics: PandaX & Dark matter. The author has an hindex of 27, co-authored 81 publications receiving 4328 citations. Previous affiliations of Xun Chen include Peking University.
Topics: PandaX, Dark matter, Physics, Xenon, Time projection chamber
Papers published on a yearly basis
Papers
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TL;DR: A new search for weakly interacting massive particles (WIMPs) using the combined low background data sets acquired in 2016 and 2017 from the PandaX-II experiment in China finds no excess events above the expected background.
Abstract: We report a new search for weakly interacting massive particles (WIMPs) using the combined low background data sets acquired in 2016 and 2017 from the PandaX-II experiment in China. The latest data set contains a new exposure of 77.1 live days, with the background reduced to a level of 0.8×10^{-3} evt/kg/day, improved by a factor of 2.5 in comparison to the previous run in 2016. No excess events are found above the expected background. With a total exposure of 5.4×10^{4} kg day, the most stringent upper limit on the spin-independent WIMP-nucleon cross section is set for a WIMP with mass larger than 100 GeV/c^{2}, with the lowest 90% C.L. exclusion at 8.6×10^{-47} cm^{2} at 40 GeV/c^{2}.
1,023 citations
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TL;DR: The weakly interacting massive particle (WIMP) dark matter search results are reported 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.
Abstract: We report the weakly interacting massive particle (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.
679 citations
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TL;DR: HLA-B*13:01 was associated with the development of the dapsone hypersensitivity syndrome among patients with leprosy and its absence wasassociated with a reduction in risk by a factor of 7.
Abstract: Background Dapsone is used in the treatment of infections and inflammatory diseases. The dapsone hypersensitivity syndrome, which is associated with a reported mortality of 9.9%, develops in about 0.5 to 3.6% of persons treated with the drug. Currently, no tests are available to predict the risk of the dapsone hypersensitivity syndrome. Methods We performed a genomewide association study involving 872 participants who had received dapsone as part of multidrug therapy for leprosy (39 participants with the dapsone hypersensitivity syndrome and 833 controls), using log-additive tests of single-nucleotide polymorphisms (SNPs) and imputed HLA molecules. For a replication analysis, we genotyped 24 SNPs in an additional 31 participants with the dapsone hypersensitivity syndrome and 1089 controls and performed next-generation sequencing for HLA-B and HLA-C typing at four-digit resolution in an independent series of 37 participants with the dapsone hypersensitivity syndrome and 201 controls. Results Genomewide ass...
253 citations
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TL;DR: Recently, direct dark matter searches are pushing the limits on the scattering of weakly interacting massive particles on normal matter so WIMPs are running out of places to hide as discussed by the authors.
Abstract: Much like ordinary matter, dark matter might consist of elementary particles, and weakly interacting massive particles are one of the prime suspects. During the past decade, the sensitivity of experiments trying to directly detect them has improved by three to four orders of magnitude, but solid evidence for their existence is yet to come. We overview the recent progress in direct dark matter detection experiments and discuss future directions. Direct dark matter searches are pushing the limits on the scattering of weakly interacting massive particles on normal matter so WIMPs are running out of places to hide.
238 citations
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TL;DR: In this article, a narrow baryon state is found in quasi-real photoproduction on a deuterium target through the decay channel pK0S→pπ+π−.
223 citations
Cited by
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Columbia University1, University of Amsterdam2, University of Bologna3, University of Mainz4, University of Münster5, University of Coimbra6, New York University Abu Dhabi7, University of Zurich8, Stockholm University9, Rensselaer Polytechnic Institute10, Max Planck Society11, Weizmann Institute of Science12, University of Freiburg13, University of Nantes14, University of California, San Diego15, University of Chicago16, Purdue University17, Rice University18, Pierre-and-Marie-Curie University19, University of California, Los Angeles20
TL;DR: In this article, a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS is reported.
Abstract: We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30±0.01) ton, resulting in a 1.0 ton yr exposure. The energy region of interest, [1.4,10.6] keVee ([4.9,40.9] keVnr), exhibits an ultralow electron recoil background rate of [82-3+5(syst)±3(stat)] events/(ton yr keVee). No significant excess over background is found, and a profile likelihood analysis parametrized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6 GeV/c2, with a minimum of 4.1×10-47 cm2 at 30 GeV/c2 and a 90% confidence level.
1,808 citations
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Columbia University1, University of Amsterdam2, University of Mainz3, University of Coimbra4, New York University Abu Dhabi5, University of Zurich6, Stockholm University7, Rensselaer Polytechnic Institute8, Max Planck Society9, Weizmann Institute of Science10, University of Freiburg11, Purdue University12, University of Nantes13, University of Bologna14, University of California, San Diego15, University of Münster16, University of Chicago17, Rice University18, Pierre-and-Marie-Curie University19, University of California, Los Angeles20
TL;DR: The first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy, are reported and a profile likelihood analysis shows that the data are consistent with the background-only hypothesis.
Abstract: We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind The blinded search used 342 live days of data acquired between November 2016 and January 2017 Inside the (1042±12)-kg fiducial mass and in the [5,40] keVnr energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (193±025)×10-4 events/(kg×day×keVee), the lowest ever achieved in such a dark matter detector A profile likelihood analysis shows that the data are consistent with the background-only hypothesis We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10 GeV/c2, with a minimum of 77×10-47 cm2 for 35-GeV/c2 WIMPs at 90% CL
1,061 citations
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TL;DR: In this article, deconfined quark matter within NJL-type models are reviewed, focusing on the regime of low temperatures and moderate densities, which is not accessible by perturbative QCD.
1,008 citations
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TL;DR: A review of the WIMP paradigm with focus on a few models which can be probed at best by these facilities, and Collider and Indirect Detection will not be neglected when they represent a complementary probe.
Abstract: Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. No conclusive signal, despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, has been detected so far. This situation might change in near future due to the advent of one/multi-TON Direct Detection experiments. We thus, find it timely to provide a review of the WIMP paradigm with focus on a few models which can be probed at best by these facilities. Collider and Indirect Detection, nevertheless, will not be neglected when they represent a complementary probe.
772 citations
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Columbia University1, University of Amsterdam2, University of Bologna3, University of Mainz4, University of Coimbra5, Weizmann Institute of Science6, New York University Abu Dhabi7, University of Zurich8, Stockholm University9, Rensselaer Polytechnic Institute10, Max Planck Society11, University of Münster12, University of Bern13, Purdue University14, École des mines de Nantes15, University of California, Los Angeles16, Rice University17
TL;DR: In this article, the expected sensitivity of the Xenon1T experiment to the spin-independent WIMP-nucleon interaction cross section was investigated based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds.
Abstract: The XENON1T experiment is currently in the commissioning phase at the Laboratori Nazionali del Gran Sasso, Italy. In this article we study the experiment's expected sensitivity to the spin-independent WIMP-nucleon interaction cross section, based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds. The total electronic recoil background in 1 tonne fiducial volume and (1, 12) keV electronic recoil equivalent energy region, before applying any selection to discriminate between electronic and nuclear recoils, is (1.80 ± 0.15) · 10(−)(4) (kg·day·keV)(−)(1), mainly due to the decay of (222)Rn daughters inside the xenon target. The nuclear recoil background in the corresponding nuclear recoil equivalent energy region (4, 50) keV, is composed of (0.6 ± 0.1) (t·y)(−)(1) from radiogenic neutrons, (1.8 ± 0.3) · 10(−)(2) (t·y)(−)(1) from coherent scattering of neutrinos, and less than 0.01 (t·y)(−)(1) from muon-induced neutrons. The sensitivity of XENON1T is calculated with the Profile Likelihood Ratio method, after converting the deposited energy of electronic and nuclear recoils into the scintillation and ionization signals seen in the detector. We take into account the systematic uncertainties on the photon and electron emission model, and on the estimation of the backgrounds, treated as nuisance parameters. The main contribution comes from the relative scintillation efficiency Script L(eff), which affects both the signal from WIMPs and the nuclear recoil backgrounds. After a 2 y measurement in 1 t fiducial volume, the sensitivity reaches a minimum cross section of 1.6 · 10(−)(47) cm(2) at m(χ) = 50 GeV/c(2).
580 citations