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Journal of Ambient Intelligence and Humanized computing 2019年第5期11卷 1903-1903页

作者： Bao, Zhenkun Guo, Yanqing Li, Xiaolong Zhang, Yi Xu, Meng Luo, Xiangyang State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou China Zhengzhou Science and Technology Institute Zhengzhou China School of Information and Communication Engineering Dalian University of Technology Dalian China Institute of Information Science Beijing Jiaotong University Beijing China

The article “A robust image steganography based on the concatenated error correction encoder and discrete cosine transform coefficients” written by Zhenkun Bao et al. was originally published electronically on the p...

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Dynamic formation of quasicondensate and spontaneous vortices in a strongly interacting Fermi gas

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arXiv 2019年

作者： Liu, Xiang-Pei Yao, Xing-Can Deng, Youjin Wang, Yu-Xuan Wang, Xiao-Qiong Li, Xiaopeng Chen, Qijin Chen, Yu-Ao Pan, Jian-Wei Hefei National Laboratory for Physical Sciences at the Microscale Department of Modern Physics University of Science and Technology of China Hefei230026 China Shanghai Branch CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Shanghai201315 China Shanghai Research Center for Quantum Sciences Shanghai201315 China State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computing Department of Physics Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China MinJiang Collaborative Center for Theoretical Physics College of Physics and Electronic Information Engineering Minjiang University Fuzhou350108 China

We report an experimental study of quench dynamics across the superfluid transition temperature Tc in a strongly interacting Fermi gas by ramping down the trapping potential. The nonzero quasi-condensate number N0 at temperature significantly above Tc in the unitary and the BEC regimes reveals the pseudogap physics. Below Tc, a rapid growth of N0 is accompanied by spontaneous generation of tens of vortices. We observe a power law scaling of the vortex density versus the quasi-condensate formation time, consistent with the Kibble-Zurek theory. Our work provides an example of studying emerged many-body physics by quench dynamics and paves the way for studying the quantum turbulence in a strongly interacting Fermi gas. Copyright © 2019, The Authors. All rights reserved.

关键词： Electron gas

Observation of a dynamical sliding phase superfluid with P-band bosons

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arXiv 2018年

作者： Niu, Linxiao Jin, Shengjie Chen, Xuzong Li, Xiaopeng Zhou, Xiaoji School of Electronics Engineering and Computer Science Peking University Beijing100871 China State Key Laboratory of Surface Physics Institute of Nanoelectronics and Quantum Computing Department of Physics Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China

Sliding phases have been long sought-after in the context of coupled XY-models, of relevance to various many-body systems such as layered superconductors, free-standing liquid-crystal films, and cationic lipid-DNA complexes. Here we report an observation of a dynamical sliding-phase superfluid that emerges in a nonequilibrium setting from the quantum dynamics of a three-dimensional ultracold atomic gas loaded into the P-band of a one-dimensional optical lattice. A shortcut loading method is used to transfer atoms into the P-band at zero quasi-momentum within a very short time duration. The system can be viewed as a series of "pancake"-shaped atomic samples. For this far-out-of-equilibrium system, we find an intermediate time window with lifetime around tens of milliseconds, where the atomic ensemble exhibits robust superfluid phase coherence in the pancake directions, but no coherence in the lattice direction, which implies a dynamical sliding-phase superfluid. The emergence of the sliding phase is attributed to a mechanism of cross-dimensional energy transfer in our proposed phenomenological theory, which is consistent with experimental measurements. This experiment potentially opens up a novel venue to search for exotic dynamical phases by creating high-band excitations in optical lattices. Copyright © 2018, The Authors. All rights reserved.

关键词： Liquid films

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

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arXiv 2022年

作者： Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, L.X. Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, J.T. Cao, Zhe Chang, J. Chang, J.F. Chen, E.S. Chen, Liang Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, Y. Cheng, H.L. Cheng, N. Cheng, Y.D. Cui, S.W. Cui, X.H. Cui, Y.D. D'Ettorre Piazzoli, B. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu Della Volpe, D. Duan, K.K. Fan, J.H. Fan, Y.Z. Fan, Z.X. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, S.L. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S. Hu, S.C. Hu, X.J. Huang, D.H. Huang, W.H. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Ji, X.L. Jia, H.Y. Jia, K. Jiang, K. Jiang, Z.J. Jin, M. Kang, M.M. Ke, T. Kuleshov, D. Levochkin, K. Li, B.B. Li, Cheng Li, Cong Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li, W.L. Li, X.R. Li, Xin Li, Y.Z. Li, Zhe Li, Zhuo Liang, E.W. Liang, Y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Long, W.J. Lu, R. Luo, Q. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Masood, A. Min, Z. Mitthumsiri, W. Nan, Y.C. Ou, Z.W. Pang, B.Y. Pattarakijwanich, P. Pei, Z.Y. Qi, M.Y. Qi, Y.Q. Qiao, B.Q. Qin, J.J. Ruffolo, D. Sáiz, A. Shao, C.Y. Shao, L. Shchegolev, O. Sheng, X.D. Shi, J.Y. Song, H.C. Stenkin, Yu.V. Stepanov, V. Su, Y. Sun, Q.N. Sun, X.N. Sun, Z.B. Tam, P.H.T. Tang, Z.B. Tian, W.W. Wang, B.D. Wang, C. Wang, H. Wang, H.G. Wang, J.C. Wang, J.S. Key Laboratory of Particle Astrophyics Experimental Physics Division Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China Tianfu Cosmic Ray Research Center Sichuan Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 Heidelberg69029 Germany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Anhui Hefei230026 China School of Physical Science and Technology School of Information Science and Technology Southwest Jiaotong University Sichuan Chengdu610031 China College of Physics Sichuan University Sichuan Chengdu610065 China School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Hebei Normal University Hebei Shijiazhuang050024 China Zhuhai519000 China Dipartimento di Fisica Dell'Università di Napoli 'Federico II' Complesso Universitario di Monte Sant'Angelo via Cinthia Napoli80126 Italy School of Physics and Astronomy Yunnan University Yunnan Kunming650091 China Département de Physique Nucléaire et Corpusculaire Faculté de Sciences Université de Genève 24 Quai Ernest Ansermet Geneva1211 Switzerland Institute of Frontier and Interdisciplinary Science Shandong University Shandong Qingdao266237 China Department of Engineering Physics Tsinghua University Beijing100084

The kilometer squarearray (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γrays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 105and 109GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission. © 2022, CC BY.

关键词： Gamma rays

Cu/ZnO Catalysts: Cu/ZnO Catalysts Derived from Bimetallic Metal–Organic Framework for Dimethyl Ether Synthesis from Syngas with Enhanced Selectivity and Stability (Small 14/2020)

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Small 2020年第14期16卷

作者： Fuping Li Min Ao Gia Hung Pham Jaka Sunarso Yanping Chen Jian Liu Kai Wang Shaomin Liu Discipline of Chemical Engineering WA School of Mines: Minerals Energy and Chemical Engineering Curtin University GPO Box U1987 Perth Western Australia 6845 Australia Research Centre for Sustainable Technologies Faculty of Engineering Computing and Science Swinburne University of Technology Jalan Simpang Tiga Kuching 93350 Sarawak Malaysia State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian National Laboratory for Clean Energy 457 Zhongshan Road Dalian 116023 China DICP-Surrey Joint Centre for Future Materials Department of Chemical and Process Engineering University of Surrey Guildford Surrey UK Beijing Advanced Innovation Centre for Soft Matter Science and Engineering College of Chemical Engineering Beijing University of Chemical Technology Beijing 100029 China

A Formalization Research on Web Server and Scheduling Strategy for Heterogeneity

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A Formalization Research on Web Server and Scheduling Strate...

2016 IEEE advanced Information Management,Communicates,Electronic and Automation Control Conference(IMCEC 2016)

作者： Bolin Ma Zheng Zhang Yongsheng Zhu State key Laboratory of Mathematical Engineering And Advanced Computing MEAC

ISBN: (纸本)9781509001668

Most web service systems are built in a static configuration web server or re dundant same web ***,traditional web service system make it easy for a cyber adversary to plan and launch *** improve the cyber security,mimic security defense where heterogeneity play an important role has been proposed to increase the difficulty for the adversary to launch successful *** this paper,we first present a formal description of heterogeneous web servers and a method how to measure the heterogeneity of web *** addition,we also present the scheduling strategy for heterogeneous web servers and demonstrate the effectiveness of this strategy in a general heterogeneous web service *** strategy of heterogeneous web servers scheduling can disrupt the vicious scan,deceive the judgment about vulnerability and prevent some vulnerabilities being found that make vulnerability attacks difficult.

关键词： Cyb er Security Heterogeneity Scheduling Strategy

Peta-electron volt gamma-ray emission from the Crab Nebula

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arXiv 2021年

作者： Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, L.X. Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, H. Cai, J.T. Cao, Zhe Chang, J. Chang, J.F. Chen, B.M. Chen, E.S. Chen, J. Chen, Liang Chen, Liang Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.L. Chen, Y. Cheng, N. Cheng, Y.D. Cui, S.W. Cui, X.H. Cui, Y.D. Piazzoli, B. D'Ettorre Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu Volpe, D. della Dong, X.J. Duan, K.K. Fan, J.H. Fan, Y.Z. Fan, Z.X. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, Y.L. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Ge, M.M. Geng, L.S. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, J.C. He, S.L. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, C. Hou, X. Hu, H.B. Hu, S. Hu, S.C. Hu, X.J. Huang, D.H. Huang, Q.L. Huang, W.H. Huang, X.T. Huang, X.Y. Huang, Z.C. Ji, F. Ji, X.L. Jia, H.Y. Jiang, K. Jiang, Z.J. Jin, C. Ke, T. Kuleshov, D. Levochkin, K. Li, B.B. Li, Cheng Li, Cong Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, Jie Li, Jian Li, K. Li, W.L. Li, X.R. Li, Xin Li, Xin Li, Y. Li, Y.Z. Li, Zhe Li, Zhuo Liang, E.W. Liang, Y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, Ruoyu Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Liu, Z.X. Long, W.J. Lu, R. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Masood, A. Min, Z. Mitthumsiri, W. Montaruli, T. Nan, Y.C. Pang, B.Y. Pattarakijwanich, P. Pei, Z.Y. Qi, M.Y. Qi, Y.Q. Qiao, B.Q. Qin, J.J. Ruffolo, D. Rulev, V. Sáiz, A. Shao, L. Shchegolev, O. Sheng, X.D. Shi, J.Y. Song, H.C. Stenkin, Yu.V. Stepanov, V. Su, Y. Sun, Q.N. Sun, X.N. Sun, Z.B. Tam, P.H.T. Tang, Z.B. Tian, W.W. Wang, B.D. Key Laboratory of Particle Astrophyics & Experimental Physics Division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China Tianfu Cosmic Ray Research Center Sichuan Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 Heidelberg69029 Germany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Anhui Hefei230026 China School of Physical Science and Technology School of Information Science and Technology Southwest Jiao-tong University Sichuan Chengdu610031 China College of Physics Sichuan University Sichuan Chengdu610065 China School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China School of Physics and Technology Wuhan University Hubei Wuhan430072 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Hebei Normal University Hebei Shijiazhuang050024 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China Sun Yat-sen University Guangdong Zhuhai519000 China Dipartimento di Fisica dell’Università di Napoli "Federico II" Complesso Universitario di Monte Sant’Angelo via Cinthia Napoli80126 Italy School of Physics and Astronomy Yunnan University Yunnan Kunming650091 China D’epartement de Physique Nucl’eaire et Corpusculaire Facult’e de Sciences Universit’e de Genève 24 Quai Ernest Ansermet Geneva1211 Switzerland Institute of Frontier and Interdisciplinary Science Shan

The Crab pulsar and the surrounding nebula powered by the pulsar’s rotational energy through the formation and termination of a relativistic electron-positron wind is a bright source of gamma-rays carrying crucial information about this complex conglomerate. We report the detection of γ-rays with a spectrum showing gradual steepening over three energy decades, from 5 × 10−4 to 1.1 petaelectronvolt (PeV). The ultra-high-energy photons exhibit the presence of a PeV electron accelerator (a pevatron) with an acceleration rate exceeding 15 % of the absolute theoretical limit. Assuming that unpulsed γ-rays are produced at the termination of the pulsar’s wind, we constrain the pevatron’s size, between 0.025 and 0.1 pc, and the magnetic field, ≈ 110µG. The production rate of PeV electrons, 2.5×1036erg s−1, constitutes 0.5% of the pulsar’s spin-down luminosity, although we do not exclude a non-negligible contribution of PeV protons to the production of the highest energy γ-rays. Copyright © 2021, The Authors. All rights reserved.

关键词： Pulsars

Generation and detection of coherent longitudinal acoustic waves in ultrathin 1T'-MoTe2

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arXiv 2019年

作者： Rivas, Nicolas Zhong, Shazhou Dekker, Tina Cheng, Meixin Gicala, Patrick Chen, Fangchu Luo, Xuan Sun, Yuping Petruk, Ariel A. Pichugin, Kostyantyn Tsen, Adam W. Sciaini, Germán Ultrafast Electron Imaging Lab Department of Chemistry Waterloo Institute for Nanotechnology University of Waterloo WaterlooONN2L3G1 Canada Institute for Quantum Computing Department of Physics and Astronomy Department of Electrical and Computer Engineering Department of Chemistry University of Waterloo WaterlooONN2L3G1 Canada Key Laboratory of Materials Physics Institute of Solid-State Physics Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China High Magnetic Field Laboratory Chinese Academy of Sciences Hefei230031 Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China

Layered transition metal dichalcogenides have attracted substantial attention owing to their versatile functionalities and compatibility with current nanofabrication technologies. Thus, noninvasive means to determine the mechanical properties of nanometer (nm) thick specimens are of increasing importance. Here, we report on the detection of coherent longitudinal acoustic phonon modes generated by impulsive femtosecond (fs) optical excitation. Broadband fs-transient absorption experiments in 1T-f-MoTe2 flakes as a function of thickness (7 nm . 30 nm) yield a longitudinal sound speed of vl = (2990± 90) m s-1. In addition, temperature dependent measurements unveil a linear decrease of the normalized Young-fs modulus El/El,295Kwith a slope of δ(***,%' ))/δT = (.2.0± 0.1) 10-3K-1and no noticeable change caused by the Td-1T-f structural phase transition or variations in film thickness. Copyright © 2019, The Authors. All rights reserved.

关键词： Elastic moduli

Performance of LHAASO-WCDA and Observation of Crab Nebula as a Standard Candle

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arXiv 2021年

作者： Aharonian, F. An, Q. Axikegu Bai, L.X. Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, H. Cai, J.T. Cao, Z. Cao, Z. Chang, J. Chang, J.F. Chang, X.C. Chen, B.M. Chen, J. Chen, L. Chen, L. Chen, L. Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.L. Chen, Y. Cheng, N. Cheng, Y.D. Cui, S.W. Cui, X.H. Cui, Y.D. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu Volpe, D. della Piazzoli, B. D'Ettorre Dong, X.J. Fan, J.H. Fan, Y.Z. Fan, Z.X. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, Y.L. Gao, B. Gao, C.D. Gao, Q. Gao, W. Ge, M.M. Geng, L.S. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, J.G. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, J.C. He, S.L. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, C. Hou, X. Hu, H.B. Hu, S. Hu, S.C. Hu, X.J. Huang, D.H. Huang, Q.L. Huang, W.H. Huang, X.T. Huang, Z.C. Ji, F. Ji, X.L. Jia, H.Y. Jiang, K. Jiang, Z.J. Jin, C. Kuleshov, D. Levochkin, K. Li, B.B. Li, C. Li, C. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, K. Li, W.L. Li, X. Li, X. Li, X.R. Li, Y. Li, Y.Z. Li, Z. Li, Z. Liang, E.W. Liang, Y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.S. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y.N. Liu, Z.X. Long, W.J. Lu, R. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Masood, A. Mitthumsiri, W. Montaruli, T. Nan, Y.C. Pang, B.Y. Pattarakijwanich, P. Pei, Z.Y. Qi, M.Y. Ruffolo, D. Rulev, V. Sáiz, A. Shao, L. Shchegolev, O. Sheng, X.D. Shi, J.R. Song, H.C. Stenkin, Yu V. Stepanov, V. Sun, Q.N. Sun, X.N. Sun, Z.B. Tam, P.H.T. Tang, Z.B. Tian, W.W. Wang, B.D. Wang, C. Wang, H. Wang, H.G. Wang, J.C. Wang, J.S. Wang, L.P. Wang, L.Y. Wang, R.N. Wang, W. Wang, W. Wang, X.G. Wang, X.J. Wang, X.Y. Key Laboratory of Particle Astrophyics & Experimental Physics Division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China TIANFU Cosmic Ray Research Center ChengduSichuan China State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Hefei Anhui230026 China Department of Engineering Physics Tsinghua University Beijing100084 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China National Space Science Center Chinese Academy of Sciences Beijing100190 China School of Physics Peking University Beijing100871 China Center for Astrophysics Guangzhou University GuangzhouGuangdong510006 China Sun Yat-sen University ZhuhaiGuangdong519082 China School of Physical Science and Technology Guangxi University Nanning Guangxi530004 China Hebei Normal University Shijiazhuang Hebei050024 China School of Physics and Microelectronics Zhengzhou University ZhengzhouHenan450001 China School of Astronomy and Space Science Nanjing University NanjingJiangsu210023 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences NanjingJiangsu210023 China Institute of Frontier and Interdisciplinary Science Shandong University QingdaoShandong266237 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Tsung-Dao Lee Institute & School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China School of Physical Science and Technology School of Information Science and Technology Southwest Jiaotong University ChengduSichuan610031 China College of Physics Sichuan University ChengduSichuan610065 China Ministry of Education Lhasa Tibet850000 China School of Physics and Technology Wuhan University Wuhan

The first Water Cherenkov detector of the LHAASO experiment (WCDA-1) has been operating since April, 2019. The first 10 months of data have been analyzed to test its performance by observing the Crab Nebula as a standard candle. The WCDA-1 achieves the sensitivity of 65 mCU per year with a statistical threshold of 5 σ. In order to do so, 97.7% cosmic ray background rejection rate around 1 TeV and 99.8% around 6 TeV with an approximately photon acceptance about 50% by using the compactness of the shower footprints to be greater than 10 as the discriminator between gamma induced showers and the cosmic ray backgrounds. The angular resolution is measured using the Crab Nebula as a point source about 0.45◦ at 1 TeV and better than 0.2◦ above 6 TeV with the pointing accuracy better than 0.05◦. They are all matching the design specifications. The energy resolution is found 33% for gamma rays around 6 TeV. The spectral energy distribution of the Crab Nebula in the range from 500 GeV and 15.8 TeV is measured and in agreement with results of other TeV gamma ray observatories. © 2021, CC BY.

关键词： Spectroscopy

γ-ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich Kr94,95,96

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Physical Review C 2022年第2期105卷 024302-024302页

作者： R.-B. Gerst A. Blazhev K. Moschner P. Doornenbal A. Obertelli K. Nomura J.-P. Ebran S. Hilaire J. Libert G. Authelet H. Baba D. Calvet F. Château S. Chen A. Corsi A. Delbart J.-M. Gheller A. Giganon A. Gillibert V. Lapoux T. Motobayashi M. Niikura N. Paul J.-Y. Roussé H. Sakurai C. Santamaria D. Steppenbeck R. Taniuchi T. Uesaka T. Ando T. Arici F. Browne A. M. Bruce R. Caroll L. X. Chung M. L. Cortés M. Dewald B. Ding F. Flavigny S. Franchoo M. Górska A. Gottardo J. Jolie A. Jungclaus J. Lee M. Lettmann B. D. Linh J. Liu Z. Liu C. Lizarazo S. Momiyama S. Nagamine N. Nakatsuka C. R. Nita C. Nobs L. Olivier R. Orlandi Z. Patel Zs. Podolyák M. Rudigier T. Saito C. Shand P.-A. Söderström I. Stefan V. Vaquero V. Werner K. Wimmer Z. Xu Institut für Kernphysik Universität zu Köln 50937 Köln Germany RIKEN Nishina Center Wako Saitama 351-0198 Japan IRFU CEA Université Paris-Saclay 91191 Gif-sur-Yvette France Department of Physics Faculty of Science University of Zagreb HR-10000 Zagreb Croatia CEA DAM DIF F-91297 Arpajon France Laboratoire Matière en Conditions Extrêmes CEA Université Paris-Saclay 91680 Bruyères-le-Châtel France School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China Department of Physics University of Tokyo 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan Laboratoire Kastler Brossel Sorbonne Université CNRS ENS-PSL Research University Collège de France Case 74 4 Place Jussieu F-75005 Paris France GSI Helmholtzzentrum für Schwerionenforschung GmbH 64291 Darmstadt Germany School of Computing Engineering and Mathematics University of Brighton Brighton BN2 4GJ United Kingdom Department of Physics University of Surrey Guildford GU2 7XH United Kingdom Institute for Nuclear Science and Technique VINATOM 179 Hoang Quoc Viet Road Cau Giay Hanoi Vietnam Institut für Kernphysik Technische Universität Darmstadt 64289 Darmstadt Germany Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China Institut de Physique Nucléaire CNRS-IN2P3 Université Paris-Saclay 91406 Orsay Cedex France LPC Caen CNRS/IN2P3 Normandie Université ENSICAEN UNICAEN 14000 Caen France Instituto de Estructura de la Materia CSIC 28006 Madrid Spain Department of Physics The University of Hong Kong Pokfulam 999077 Hong Kong China School of Nuclear Science and Technology University of Chinese Academy of Sciences Beijing 100049 China Department of Physics Faculty of Science Kyoto University Kyoto 606-8502 Japan Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH) R-077125 Bucharest Romania Advanced Science Research Center Japan Atomic Energy Agency Tokai Ibaraki 319-1195 Japan

We report on γ-ray spectroscopy of low-lying excited states in the neutron-rich Kr94,95,96 isotopes measured as part of the “Shell Evolution And Search for Two-plus energies At RIBF” (SEASTAR) campaign at the RIKEN Radioactive Isotope Beam Factory. Excited yrast and non-yrast states were observed, and half-lives extracted via geant4 simulations. In Kr94,96 candidates for the 31− state were identified. For Kr95, the prompt SEASTAR data were combined with delayed spectroscopic data measured with the EURICA array to observe transitions on top of the known (7/2)+ isomer at a level energy of 195.5(3) keV. The comparison of the new experimental results with five-dimensional collective Hamiltonian (5DCH) and mapped interacting boson model (IBM) calculations, both using the Gogny D1M interaction, could suggest oblate-prolate shape coexistence already in Kr96.

关键词： Electromagnetic transitions Isomer decays Nuclear structure & decays 90 ≤ A ≤ 149