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arXiv 2025年

作者： Yan, Xiao Z. Chen, Yang M. Geng, Hua Y. Wang, Yi F. Sun, Yi Zhang, Lei L. Wang, Hao Xu, Yin L. National Key Laboratory of Shock Wave and Detonation Physics Institute of Fluid Physics CAEP P.O. Box 919-102 Mianyang621900 China School of Science Jiangxi University of Science and Technology Jiangxi Ganzhou341000 China HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing100871 China Jiangxi Provincial Key Laboratory of Particle Technology Jiangxi Ganzhou341000 China

Understand the nature of liquid structure and its evolution under different conditions is a major challenge in condensed physics and materials science. Here, we report a pressure-induced structure change spanning a wide pressure range in liquid-state lithium hydride (LiH) by first-principles molecular dynamic simulations. This behavior can be described as a continuous crossover from low pressure liquid with Li+H- duality symmetry to high pressure one with broken of duality symmetry. The thermodynamic quantities such as heat capacity and ionic transport properties such as diffusivity are also saliently impacted. It is important to stress that such behavior is firstly predicted for this category of materials, which is ubiquitous in universe as well as in industry applications. Lastly, a comprehensive high-pressure high-temperature phase diagram of LiH is constructed, which embodies rich physics in this previously-thought-simple ionic compound. © 2025, CC BY.

关键词： Specific heat

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First observation of shock waves induced by laser-accelerated proton beams

arXiv

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arXiv 2025年

作者： Fang, Yanlyu Le, Xiaoyun Yan, Yang Li, Chentong Huang, Mingfeng Yan, Yiting Yan, Xueqing Lin, Chen State Key Laboratory of Nuclear Physics and Technology and CAPT Peking University Beijing100871 China Department of Applied Physics School of Science Beijing University of Aeronautic and Astronautic Beijing100083 China Beijing Laser Acceleration Innovation Center Huairou Beijing101400 China Institute of Guangdong Laser Plasma Technology Baiyun Guangzhou510540 China

We demonstrate, for the first time, that laser-accelerated protons can induce shock waves in materials. The ultra-short pulse width of laser-driven protons enables them to deposit energy instantaneously, leading to an intense thermodynamic effect that heats and pressurizes materials violently, thereby generating shock waves. In contrast, laser-accelerated electrons do not possess this capability. Our simulations and experiments reveal that the flow intensity of the proton beam, which includes information on both the proton number and pulse width, directly correlates with shock waves. This finding not only provides a new method for characterizing the high flow intensity of laser-driven protons but also expands their applications in studying extreme states of matter. Copyright © 2025, The Authors. All rights reserved.

关键词： Thermodynamic properties

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String tension and Polyakov loop in a rotating background

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Physical Review D 2025年第2期111卷 026020-026020页

作者： Jun-Xia Chen Sheng Wang Defu Hou Hai-Cang Ren Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOS) Central China Normal University Wuhan 430079 China School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China

We study the influence of a rotation on the string tension and the temperature of the confinement-deconfinement phase transition of gluodynamics by gauge/gravity duality. We explore two distinct approaches, global transformation and local transformation, to introduce rotation and compare the results. It is shown that the string tension extracted from the free energy in the presence of a heavy quarkonium decreases with increasing angular velocity, while the transition temperature determined by the Polyakov loop increases with increasing angular velocity, which is in line with lattice simulations.

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Optimizing the lattice design of a diffraction-limited storage ring with a rational combination of particle swarm and genetic algorithms

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Chinese physics C 2017年第2期41卷 166-176页

作者：焦毅徐刚 Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

In the lattice design of a diffraction-limited storage ring（DLSR） consisting of compact multi-bend achromats（MBAs）, it is challenging to simultaneously achieve an ultralow emittance and a satisfactory nonlinear performance, due to extremely large nonlinearities and limited tuning ranges of the element parameters. Nevertheless, in this paper we show that the potential of a DLSR design can be explored with a successive and iterative implementation of the multi-objective particle swarm optimization（MOPSO） and multi-objective genetic algorithm（MOGA）. For the High Energy Photon Source, a planned kilometer-scale DLSR, optimizations indicate that it is feasible to attain a natural emittance of about 50 pm·rad, and simultaneously realize a sufficient ring acceptance for on-axis longitudinal injection, by using a hybrid MBA lattice. In particular, this study demonstrates that a rational combination of the MOPSO and MOGA is more effective than either of them alone, in approaching the true global optima of an explorative multi-objective problem with many optimizing variables and local optima.

关键词： diffraction-limited storage ring High Energy Photon Source multi-objective particle swarm optimization multi-objective genetic algorithm lattice design

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Development of a high-power and ultra-high-vacuum waveguide coupler working at C/X band

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Chinese physics C 2015年第5期39卷 117-120页

作者：贺祥赵风利王湘鉴 Laboratory of Particle Acceleration Physics & Technology Institute of High Energy PhysicsChinese Academy of Sciences

Waveguide directional couplers working at 5.712/11.9924 GHz are developed. Even holes symmetrical to the structure are drilled along the central line of the narrow-wall of the waveguide, which are used to couple the electromagnetic power from the main-waveguide to the sub-waveguide. The final prototypes have achieved satisfactory performances of high-power, ultra-high-vacuum and high-directivity. The microwave measurement results are also qualified.

关键词： high-power ultra-high-vacuum high-directivity C-band X-band waveguide coupler

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B→KK¯(πη)h decays in the presence of isovector scalar resonances a0(980,1450)

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Physical Review D 2025年第5期111卷 056012-056012页

作者： Si-Yang Wang Zhi-Qing Zhang Zhi-Jie Sun Jian Chai Peng Li Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE) Central China Normal University Wuhan Hubei 430079 China Institute of Theoretical Physics School of Sciences Henan University of Technology Zhengzhou Henan 450001 China Bingtuan Xingxin Vocational and Technical College Xinjiang 841007 China Institute for Complexity Science Henan University of Technology Zhengzhou Henan 450001 China

Different from the previous treatment in a two-body framework, we introduce the dimeson distribution amplitudes (DAs) to describe the strong dynamics between the S-wave resonances a0(980,1450) and the KK¯(πη) pair, where the Gegenbauer coefficient required is determined from the experimental data on the timelike form factors involved. The branching ratios and direct CP asymmetries of the decays B→a0(′)h→KK¯(πη)h, with a0=a0(980), a0′=a0(1450) and h referring to a pion or a kaon, are then calculated in the perturbative QCD (PQCD) approach. We find that the branching ratios of the corresponding quasi-two-body decays B→a0(′)K obtained with the narrow width approximation are closer to those predicted in the QCD factorization (QCDF) approach compared to the previous PQCD calculations, no matter a three-body or a two-body framework is assumed. Furthermore, all our predictions for these B→a0(′)K decays are below the current experimental upper limits except for those of decays B0→a0(′)−K+, which are (slightly) larger than the upper limits. Under the narrow width approximation, the branching ratios of the decays B+→a0(′)+π0, B0→a0(′)+π−, and B0→a0(′)0π0 are comparable to or agree well with the previous PQCD and the QCDF calculations. While for the decays B+→a0(′)0π+ and B0→a0(′)−π+, their branching ratios are predicted to be unexpectedly large, for example, the obtained branching ratio of decay B+→a00π+ is even higher than the current experimental upper limit. For the decays B0→a0(′)−K+,a0(′)0π0,a0(′)+π−, where the tree and the penguin amplitudes are comparable in magnitude, the direct CP asymmetries are sensitive to the strong phases, which are very different obtained by other theoretical predictions for some channels. Therefore, it is very important to accurately determine the strong phases of these decays, which are crucial to precisely predict the direct CP asymmetries and further clarify the inner structures of the resonances a0(980) and a0(1450).

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Dark Matter Search Results from 1.54 Tonne·Year Exposure of PandaX-4T

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Physical Review Letters 2025年第1期134卷 011805-011805页

作者： Zihao Bo Wei Chen Xun Chen Yunhua Chen Zhaokan Cheng Xiangyi Cui Yingjie Fan Deqing Fang Zhixing Gao School of Physics and Astronomy Shanghai Jiao Tong University Key Laboratory for Particle Astrophysics and Cosmology (MoE) Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240 China New Cornerstone Science Laboratory Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 201210 China Shanghai Jiao Tong University Sichuan Research Institute Chengdu 610213 China Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province Liangshan 615000 China Yalong River Hydropower Development Company Ltd. 288 Shuanglin Road Chengdu 610051 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen University Zhuhai 519082 China Department of Physics Yantai University Yantai 264005 China Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) Institute of Modern Physics Fudan University Shanghai 200433 China

In this Letter, we report the dark matter search results from the commissioning run (Run0) and the first science run (Run1) of the PandaX-4T experiment. The two datasets were processed with a unified procedure, with the Run1 data treated blindly. The data processing is improved compared to previous work, unifying the low-level signal reconstruction in a wide energy range up to 120 keV. With a total exposure of 1.54 tonne·year, no significant excess of nuclear recoil events is found. The lowest 90% confidence level exclusion on the spin-independent cross section is 1.6×10−47 cm2 at a dark matter mass of 40 GeV/c2. Our results represent the most stringent constraint for a dark matter mass above 100 GeV/c2.

关键词： Dark Matter

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Effect of near-Earth thunderstorm electric fields on the flux of cosmic ray air showers in LHAASO-KM2A

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Physical Review D 2025年第6期111卷 063023-063023页

作者： C. Yang X. X. Zhou H. H. He D. H. Huang X. J. Chen T. Zhou K. J. Guo School of Physical Science and Technology Southwest Jiaotong University Chengdu 610031 China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China

The Large High Altitude Air Shower Observatory (LHAASO) is located at Haizi Mountain (4410 m a. s. l.), Daocheng, Sichuan province, China. Due to its high-altitude location with frequent thunderstorm activities, the LHAASO is suited for studying the effects of near-Earth thunderstorm electric fields on cosmic ray air showers. In this paper, Monte Carlo simulations are performed with corsika and g4km2a to analyze the flux variations of cosmic ray air showers detected by the kilometer-square array of LHAASO (LHAASO-KM2A) during thunderstorms. The strength, polarity, and layer thickness of the atmospheric electric field (AEF) during thunderstorm are found to be associated with the shower rate variations. The flux of shower events satisfying trigger conditions of the LHAASO-KM2A increases with field intensity, particularly within negative fields, and the enhanced amplitude is more than 5% in −600 V/cm and 12% in AEF of −1000 V/cm, whereas it increases only by 1% and 7% in equivalent positive fields, respectively. While in positive fields ranging from 0 to 400 V/cm, the shower rate decreases with smaller amplitudes. Furthermore, the shower rate increases dramatically with the AEF layer thickness until a certain value, above which the variation trend slows down. The dependence of the trigger rate variation on the primary zenith angle has also been revealed, increasing in lower zenith angle ranges and showing opposite behavior in higher ones. Additionally, we study that the relationship between the trigger rate variations and the primary energies, and find the enhanced amplitude of the shower rate decreases with increasing primary energy. Simultaneously, the shower events with lower primary energy show a significant increase, whereas events with higher primary energy are hardly affected during thunderstorms. These simulation results offer valuable insights into the variation of the trigger rate detected by LHAASO-KM2A during thunderstorms and are beneficial for understa

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Search for MeV-Scale Axionlike particles and Dark Photons with PandaX-4T

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Physical Review Letters 2025年第7期134卷 071004-071004页

作者： Tao Li Zihao Bo Wei Chen Xun Chen Yunhua Chen Zhaokan Cheng Xiangyi Cui Yingjie Fan Deqing Fang Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen University Zhuhai 519082 China SJTU Paris Elite Institute of Technology Shanghai Jiao Tong University Shanghai 200240 China School of Physics and Astronomy Shanghai Jiao Tong University Key Laboratory for Particle Astrophysics and Cosmology (MoE) Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240 China New Cornerstone Science Laboratory Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 201210 China Shanghai Jiao Tong University Sichuan Research Institute Chengdu 610213 China Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province Yalong River Hydropower Development Company Ltd. 288 Shuanglin Road Chengdu 610051 China Department of Physics Yantai University Yantai 264005 China Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) Institute of Modern Physics Fudan University Shanghai 200433 China

Axionlike particles (ALPs) and dark photons (DPs) are viable dark matter particle candidates. We have searched for possible ALP/DP signals in the PandaX-4T liquid xenon detector using 440 kg·yr of data. A binned likelihood fit is constructed to search for possible mono-energetic peaks induced by the absorption processes between ALPs/DPs and atomic electrons of xenon. A detailed temporal model of decays associated with xenon isotopes is introduced to constrain the number of background events. No signal excess over background expectations is observed, and we have established the most stringent exclusion limits for most ALP/DP masses across the range of 150 keV/c2 to 1 MeV/c2. The improvement is particularly significant within the mass range of 150–400 keV/c2, with the average factor of 3.5 compared to previous results.

关键词： Photons

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Galaxy and halo properties around cosmic filaments from Sloan Digital Sky Survey Data Release 7 and the ELUCID simulation

arXiv

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arXiv 2025年

作者： Zhang, Youcai Yang, Xiaohu Guo, Hong Wang, Peng Shi, Feng Shanghai Astronomical Observatory Nandan Road 80 Shanghai200030 China State Key Laboratory of Dark Matter Physics Tsung-Dao Lee Institute School of Physics and Astronomy Shanghai Jiao Tong University Shanghai201210 China Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai200240 China School of Aerospace Science and Technology Xidian University Xi’an710126 China

Using galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) along with haloes from the dark matter only constrained ELUCID (Exploring the Local Universe with the reConstructed Initial Density field) simulation, we examine the properties of galaxies and haloes with respect to their distance to cosmic filaments, determined by the medial-axis thinning technique of the COsmic Web Skeleton (COWS) method. Our findings suggest that galaxies or subhaloes grow in mass as they approach these filaments. Galaxies exhibit a redder colour and diminished specific star formation rates as they approach these filaments. Additionally, older subhaloes tend to be more common near the central regions of these filaments. Elliptical galaxies are more frequently found than spiral galaxies in the central regions of the filaments. Lower-mass galaxies typically display reduced sizes in proximity to filaments, whereas higher-mass galaxies tend to exhibit increased sizes when close to filaments. Moreover, the concentration and spin of the haloes grow as they approach the filaments. These findings support the notion that the large-scale structure of the universe, characterized by cosmic web structures, plays a vital role in shaping galaxy and halo properties. Copyright © 2025, The Authors. All rights reserved.

关键词： Dark Matter

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