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(DarkAI)Mapping the large-scale density field of dark matter using artificial intelligence

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Science China(physics,Mechanics & Astronomy) 2024年第1期67卷 143-159页

作者： Zitong Wang Feng Shi Xiaohu Yang Qingyang Li Yanming Liu Xiaoping Li School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Department of Astronomy School of Physics and Astronomyand Shanghai Key Laboratory for Particle Physics and CosmologyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute and Key Laboratory for particle physics Astrophysics and CosmologyMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China Institute for Astronomy University of EdinburghRoyal ObservatoryEdinburgh EH93HJUnited Kingdom

Herein,we present a deep-learning technique for reconstructing the dark-matter density field from the redshift-space distribution of dark-matter halos.We built a UNet-architecture neural network and trained it using the COmoving Lagrangian Acceleration fast simulation,which is an approximation of the N-body simulation with 5123 particles in a box size of 500 h^(-1)Mpc.Further,we tested the resulting UNet model not only with training-like test samples but also with standard N-body simulations,such as the Jiutian simulation with 61443particles in a box size of 1000 h^(-1)Mpc and the ELUCID simulation,which has a different cosmology.The real-space dark-matter density fields in the three simulations can be reconstructed reliably with only a small reduction of the cross-correlation power spectrum at 1%and 10%levels at k=0.1 and 0.3 h Mpc-1,respectively.The reconstruction clearly helps to correct for redshift-space distortions and is unaffected by the different cosmologies between the training(Planck2018)and test samples(WMAP5).Furthermore,we tested the application of the UNet-reconstructed density field to obtain the velocity&tidal field and found that this approach provides better results compared with the traditional approach based on the linear bias model,showing a 12.2%improvement in the correlation slope and a 21.1%reduction in the scatter between the predicted and true velocities.Thus,our method is highly efficient and has excellent extrapolation reliability beyond the training set.This provides an ideal solution for determining the three-dimensional underlying density field from the plentiful galaxy survey data.

关键词： dark matter large-scale structure cosmology

Exploring hidden-charm and hidden-strange hexaquark states from lattice QCD

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Science China(physics,Mechanics & Astronomy) 2024年第1期67卷 30-37页

作者： Hang Liu Jinchen He Liuming Liu Peng Sun Wei Wang Yi-Bo Yang Qi-An Zhang INPAC Key Laboratory for Particle Astrophysics and Cosmology(MOE)Shanghai Key Laboratory for Particle Physics and CosmologySchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Maryland center for Fundamental physics Department of PhysicsUniversity of MarylandCollege ParkMaryland 20742USA Institute of Modern physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Department of physics and Institute of Theoretical physics Nanjing Normal UniversityNanjing 210023China Southern center for nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China CAS Key Laboratory of Theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical physics Asia-Pacific Beijing 100049/Hangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of physics Beihang UniversityBeijing 102206China

Based on five different ensembles of newly generated(2+1)-flavor configurations with pion mass of approximately mπ■(140-310)MeV,we present a lattice analysis of hidden-charm and hidden-strange hexaquarks with the quark content■.The correlation matrices of two types of operators with JPC=0++,0-+,1++and 1--are simulated to extract the masses of the hexaquark candidates,which are subsequently extrapolated to the physical pion mass and continuum limit.The results indicate that ground state masses are below the■threshold and provide a characteristic signal for the experimental discovery of hexaquark candidates,which may enrich the versatile structure of multiquarks;moreover,it is an indispensable step to decipher the nonperturbative nature of the fundamental interactions of quarks and gluons.

关键词： quantum chromodynamics lattice QCD multiquark states

Quasi-2D weak lensing cosmological constraints using the PDF-SYM method

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Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 44-58页

作者： Zhenjie Liu Jun Zhang Hekun Li Zhi Shen Cong Liu Department of Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory for particle physics and cosmology Shanghai 200240China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

Cosmic shear statistics,such as the two-point correlation function(2PCF),can be evaluated with the PDF-SYM method instead of the traditional weighted-sum approach.It makes use of the full PDF information of the shear estimators,and does not require weightings on the shear estimators,which can in principle introduce additional systematic biases.This work presents our constraints on S8and?mfrom the shear-shear correlations using the PDF-SYM method.The data we use is from the z-band images of the Dark Energy Camera Legacy Survey(DECa LS),which covers about 10000 deg2with more than 100 million galaxies.The shear catalog is produced by the Fourier Quad method,and well tested on the real data itself with the field-distortion effect.Our main approach is called quasi-2D as we do use the photo-z information of each individual galaxy,but without dividing the galaxies into redshift bins.We mainly use galaxy pairs within the redshift interval between 0.2 and 1.3,and the angular range from 4.7 to 180 arcmin.Our analysis yields S8=0.762±0.026 and?m=0.234±0.075,with the baryon effects and the intrinsic alignments included.The results are robust against redshift uncertainties.We check the consistency of our results by deriving the cosmological constraints from auto-correlations ofγ1andγ2separately,and find that they are consistent with each other,but the constraints from theγ1component are much weaker than that fromγ2.It implies a much worse data quality ofγ1,which is likely due to additional shear uncertainties caused by CCD electronics(according to the survey strategy of DECa LS).We also perform a pure 2D analysis,which gives S8=0.81_(-0.04)~(+0.03)and?m=0.25_(-0.05)~(+0.06).Our findings demonstrate the potential of the PDF-SYM method for precision cosmology.

关键词： weak lensing shear-shear correlations cosmological parameters observations analysis

Electrodynamics with violations of Lorentz and U(1)gauge symmetries and their Hamiltonian structures

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Chinese physics C 2024年第6期48卷 45-57页

作者：杨秀鹏李瀑飞朱涛 Institute for Theoretical physics and cosmology Zhejiang University of TechnologyHangzhou 310032China United center for Gravitational Wave physics(UCGWP) Zhejiang University of TechnologyHangzhou 310032China

This study aims to investigate Lorentz/U(1)gauge symmetry-breaking electrodynamics in the framework of the standard-model extension and analyze the Hamiltonian structure for the theory with a specific dimension of Lorentz breaking operators.For this purpose,we consider a general quadratic action of the modified electrodynamics with Lorentz/gauge-breaking operators and calculate the number of independent components of the operators at different dimensions in gauge invariance and breaking.With this general action,we then analyze how Lorentz/gauge symmetry-breaking can change the Hamiltonian structure of the theories by considering Lorentz/gauge-breaking operators with dimension as examples.We show that the Lorentz-breaking operators with gauge invariance do not change the classes of the theory constrains and the number of physical degrees of freedom of the standard Maxwell electrodynamics.When U(1)gauge symmetry-breaking operators are present,the theories generally lack a first-class constraint and have one additional physical degree of freedom compared to the standard Maxwell electrodynamics.

关键词： standard model extension electrodynamics Lorentz violations

The Influence of the Sun and Moon on the Observation of Very High Energy Gamma-ray Sources Using EAS Arrays

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Research in Astronomy and Astrophysics 2024年第6期24卷 247-254页

作者： Tao Wen Songzhan Chen Benzhong Dai School of physics and Astronomy Yunnan University Key Laboratory of particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Tianfu Cosmic Ray Research center

With great advance of ground-based extensive air shower arrays, such as LHAASO and HAWC, many very high energy(VHE) gamma-ray sources have been discovered and are being monitored regardless of the day and the night. Hence, the Sun and Moon would have some impacts on the observation of gamma-ray sources, which have not been taken into account in previous analysis. In this paper, the influence of the Sun and Moon on the observation of very high energy gamma-ray sources when they are near the line of sight of the Sun or Moon is estimated. The tracks of all the known VHE sources are scanned and several VHE sources are found to be very close to the line of sight of the Sun or Moon during some period. The absorption of very high energy gamma rays by sunlight is estimated with detailed method and some useful conclusions are achieved. The main influence is the block of the Sun and Moon on gamma rays and the shadow on the cosmic ray background. The influence is investigated considering the detector angular resolution and some strategies on data analysis are proposed to avoid the underestimation of the gamma-ray emission.

关键词： astroparticle physics methods: observational Sun: general Sun: UV radiation

Implications of neutron skin measurements on Skyrme equations of state

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Chinese physics C 2024年第6期48卷 155-161页

作者：管大为裴俊琛蒋崇基 State Key Laboratory of nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China Southern center for nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China

The recent measurements of neutron skins via parity violation in electron scattering have extracted an abnormally thick neutron skin for 208 Pb,which has significant consequences in nuclear equation of state(EoS)and neutron star observations.In this study,we perform optimizations of extended Skyrme forces in a consistent manner by including neutron skin thicknesses from PREX-Ⅱand CREX experiments and investigate nuclear EoSs and neutron stars in the GW170817 event By varying the fitting weights of neutron skins,several new Skyrme parameterizations are obtained.Our results show the competition in the fitting procedure to simultaneously describe neutron skins,other properties of finite nuclei,and neutron star observations.The prospects of resolving neutron skin issues are also discussed.

关键词： neutron skin equation of state neutron star Skyrme force

The energy response of LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals for GECAM

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nuclear Science and Techniques 2024年第2期35卷 110-122页

作者： Pei-Yi Feng Xi-Lei Sun Zheng-Hua An Yong Deng Cheng-Er Wang Huang Jiang Jun-Jie Li Da-Li Zhang Xin-Qiao Li Shao-Lin Xiong Chao Zheng Ke Gong Sheng Yang Xiao-Jing Liu Min Gao Xiang-Yang Wen Ya-Qing liu Yan-Bing Xu Xiao-Yun Zhao Jia-Cong Liu Fan Zhang Hong Lu particle and Astrophysics center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Key Laboratory of particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Experimental physics center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China State Key Laboratory of particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of nuclear Science and Technology University of South ChinaHengyang 421001China National Engineering Research center for Rare Earth Grirem Advanced Materials Co.Ltd.and General Research Institute for Nonferrous MetalsBeijing 100088China

The GECAM series of satellites utilizes LaBr_(3)(Ce),LaBr_(3)(Ce,Sr),and NaI(Tl)crystals as sensitive materials for gamma-ray detectors(GRDs).To investigate the nonlinearity in the detection of low-energy gamma rays and address the errors in the calibration of the E-C relationship,comprehensive tests and comparative studies of the three aforementioned crystals were conducted using Compton electrons,radioactive sources,and mono-energetic X-rays.The nonlinearity test results of the Compton electrons and X-rays demonstrated substantial differences,with all three crystals presenting a higher nonlinearity for X/-rays than for Compton electrons.Despite the LaBr_(3)(Ce)and LaBr_(3)(Ce,Sr)crystals having higher absolute light yields,they exhibited a noticeable nonlinear decrease in the light yield,especially at energies below 400 keV.The NaI(Tl)crystal demonstrated an"excess"light output in the 6-200 keV range,reaching a maximum"excess"of 9.2%at 30 keV in the X-ray testing and up to 15.5%at 14 keV during Compton electron testing,indicating a significant advantage in the detection of low-energy gamma rays.Furthermore,we explored the underlying causes of the observed nonlinearity in these crystals.This study not only elucidates the detector responses of GECAM,but also initiates a comprehensive investigation of the nonlinearity of domestically produced lanthanum bromide and sodium iodide crystals.

关键词： LaBr_(3)(Ce)detector LaBr_(3)(Ce,Sr)detector NaI(Tl)detector GECAM Energy response Light yield nonlinearity

Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

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nuclear Science and Techniques 2024年第1期35卷 178-187页

作者： Sheng-Da Tang Yong-Hao Chen Jing-Yu Tang Rui-Rui Fan Qiang Li Gong Li Dong Liu Zheng-Yao Jin Xing-Zhu Cui Tian-Xiang Chen Yi-Wei Yang Rong Liu Han Yi Yang Li Zhen Yang Qi An Hao-Fan Bai Jiang-Bo Bai Jie Bao Ping Cao Qi-Ping Chen Zhen Chen Zeng-Qi Cui An-Chuan Fan Chang-Qing Feng Fan-Zhen Feng Ke-Qing Gao Min-Hao Gu Chang-Cai Han Zi-Jie Han Guo-Zhu He Yong-Cheng He Yang Hong Yi-Wei Hu Han-Xiong Huang Wei-Hua Jia Hao-yu Jiang Wei Jiang Zhi-jie Jiang Ling Kang Bo Li Chao Li Jia-Wen Li Xiao Li Jie Liu Shu-Bin Liu Guang-Yuan Luan Chang-Jun Ning Bin-Bin Qi Jie Ren Zhi-Zhou Ren Xi-Chao Ruan Zhao-Hui Song Kang Sun Zhi-Xin Tan Li-Jiao Wang Peng-Cheng Wang Zhao-Hui Wang Zhong-Wei Wen Xiao-Guang Wu Xuan Wu Li-Kun Xie Yong-Ji Yu Guo-Hui Zhang Lin-Hao Zhang Mo-Han Zhang Qi-Wei Zhang Xian-Peng Zhang Yu-Liang Zhang Yue Zhang Zhi-Yong Zhang Mao-Yuan Zhao Lu-Ping Zhou Zhi-Hao Zhou Ke-Jun Zhu Sino-French Institute of nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Institute of High-Energy physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science center Dongguan 523803China School of nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China State Key Laboratory of particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China State Key Laboratory of particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China USTC Archaeometry Laboratory University of Science and Technology of ChinaHefei 230026China Institute of nuclear physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Department of Modern physics University of Science and Technology of ChinaHefei 230026China State Key Laboratory of nuclear physics and Technology School of PhysicsPeking UniversityBeijing 100871China Key Laboratory of nuclear Data China Institute of Atomic EnergyBeijing 102413China Northwest Institute of nuclear Technology Xi’an 710024China University of Chinese Academy of Sciences Beijing 100049China

Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.

关键词： CSNS White neutron beam NRTA Nuclide identification Nondestructive method

Spin asymmetry and dipole moments in τ-pair production with ultraperipheral heavy ion collisions

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Science China(physics,Mechanics & Astronomy) 2024年

作者： Dingyu Shao Bin Yan Shu-Run Yuan Cheng Zhang Department of physics Center for Field Theory and Particle Physics Fudan University Key Laboratory of nuclear physics and Ion-beam Application (MOE) Fudan University Shanghai Research center for Theoretical nuclear physics National Natural Science Foundation of China (NSFC) and Fudan University Institute of High Energy physics Chinese Academy of Sciences School of physics Peking University

The anomalous magnetic(MDM) and electric(EDM) dipole moments of the τ lepton serve as crucial indicators of new physics beyond the standard model. Leveraging azimuthal angular asymmetry as a novel tool in ultraperipheral collisions(UPCs), we attain unparalleled precision in the study of these key properties. Driven by the highly linear polarization of coherent photons, this method uniquely enables both the MDM and EDM to contribute to the cos 2? angular distribution in similar magnitudes. Importantly, our approach substantially narrows the parameter space, excluding more than half of it compared to expected UPC-based measurements reliant solely on the total cross-section. This method not only provides improved constraints but also minimizes the need for additional theoretical assumptions, and offers a novel avenue to probe the EDM effects.

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