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arXiv 2025年

作者： Sasaki, Misao Yingcharoenrat, Vicharit Zhang, Ying-Li School of Physics Science and Engineering Tongji University Shanghai200092 China Institute for Advanced Study of Tongji University Shanghai200092 China UTIAS The University of Tokyo Chiba277-8583 Japan Center for Gravitational Physics and Quantum Information Yukawa Institute for Theoretical Physics Kyoto University Kyoto606-8502 Japan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei10617 Taiwan High Energy Physics Research Unit Department of Physics Faculty of Science Chulalongkorn University Pathumwan Bangkok10330 Thailand Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China Center for Gravitation and Cosmology Yangzhou University Yangzhou225009 China

Recently, it was shown that in the absence of gravity there exist non-O(4)-symmetric instanton solutions with finite action beyond Coleman’s instantons. In this paper, focusing on the false-vacuum decay in a single scalar field in flat Euclidean space, we provide a general discussion on O(4)-symmetric instantons that are singular at the true-vacuum bubble. We find that, for the action to remain finite without introducing a UV cutoff, the potential must be unbounded from below and take the exponential form, thereby evading Coleman’s theorem. We then consider two explicit examples of such instantons and perturbatively analyze the dynamics of small deformations around them. We find that one of them does not allow regular deformations, which indicates that the O(4) symmetric solution still gives the minimum action, while the other one is found to allow regular deformations that cost no additional action at second order in perturbation. The latter example opens up the possibility of the existence of non-O(4)-symmetric solutions with lower action if we allow singular instantons with finite action. © 2025, CC BY.

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Dimensionless machine learning: imposing exact units equivariance

The Journal of Machine Learning Research

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The Journal of Machine Learning Research 2023年第1期24卷 4923-4954页

作者： Soledad Villar Weichi Yao David W. Hogg Ben Blum-Smith Bianca Dumitrascu Department of Applied Mathematics and Statistics Mathematical Institute for Data Science Johns Hopkins University Department of Technology Operations and Statistics New York University Center for Cosmology and Particle Physics Department of Physics New York University Max-Planck-Institut für Astronomie Flatiron Institute a Division of the Simons Foundation Department of Applied Mathematics and Statistics Johns Hopkins University Department of Computer Science and Technology Cambridge University

Units equivariance (or units covariance) is the exact symmetry that follows from the requirement that relationships among measured quantities of physics relevance must obey self-consistent dimensional scalings. Here, we express this symmetry in terms of a (non-compact) group action, and we employ dimensional analysis and ideas from equivariant machine learning to provide a methodology for exactly units-equivariant machine learning: For any given learning task, we first construct a dimensionless version of its inputs using classic results from dimensional analysis and then perform inference in the dimensionless space. Our approach can be used to impose units equivariance across a broad range of machine learning methods that are equivariant to rotations and other groups. We discuss the in-sample and out-of-sample prediction accuracy gains one can obtain in contexts like symbolic regression and emulation, where symmetry is important. We illustrate our approach with simple numerical examples involving dynamical systems in physics and ecology.

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Neutron capture cross section of ^(169)Tm measured at the CSNS Back-n facility in the energy region from 30 to 300 keV

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Chinese physics C 2022年第4期46卷 92-104页

作者： Jie Ren Xichao Ruan Wei Jiang Jie Bao Jincheng Wang Qiwei Zhang Guangyuan Luan Hanxiong Huang Yangbo Nie Zhigang Ge Qi An Huaiyong Bai Yu Bao Ping Cao Haolei Chen Qiping Chen Yonghao Chen Yukai Chen Zhen Chen Zengqi Cui Ruirui Fan Changqing Feng Keqing Gao Minhao Gu Changcai Han Zijie Han Guozhu He Yongcheng He Yang Hong Weiling Huang Xiru Huang Xiaolu Ji Xuyang Ji Haoyu Jiang Zhijie Jiang Hantao Jing Ling Kang Mingtao Kang Bo Li Chao Li Jiawen Li Lun Li Qiang Li Xiao Li Yang Li Rong Liu Shubin Liu Xingyan Liu Qili Mu Changjun Ning Binbin Qi Zhizhou Ren Yingpeng Song Zhaohui Song Hong Sun Kang Sun Xiaoyang Sun Zhijia Sun Zhixin Tan Hongqing Tang Jingyu Tang Xinyi Tang Binbin Tian Lijiao Wang Pengcheng Wang Qi Wang Taofeng Wang Zhaohui Wang Jie Wen Zhongwei Wen Qingbiao Wu Xiaoguang Wu Xuan Wu Likun Xie Yiwei Yang Han Yi Li Yu Tao Yu Yongji Yu Guohui Zhang Linhao Zhang Xianpeng Zhang Yuliang Zhang Zhiyong Zhang Yubin Zhao Luping Zhou Zuying Zhou Danyang Zhu Kejun Zhu Peng Zhu Key Laboratory of Nuclear Data China Institute of Atomic EnergyBeijing 102413China Institute of High Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China State Key Laboratory of Particle Detection and Electronics 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 Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Northwest Institute of Nuclear Technology Xi'an 710024China University of Chinese Academy of Sciences Beijing 100049China Department of Engineering and Applied Physics University of Science and Technology of ChinaHefei 230026China School of Physics Beihang UniversityBeijing 100083China

The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation *** background subtraction,normalization,and correction were carefully considered in the data analysis to obtain accurate cross *** the resonance at 3.9 eV,the R-matrix code SAMMY was used to determine the resonance parameters with the internal normalization *** average capture cross sections of ^(169)Tm for energy between 30 and 300 keV were extracted relative to the ^(197)Au(n,γ)*** measured cross sections of the ^(169)Tm(n,γ)reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this study and described in terms of average resonance parameters using a Hauser-Feshbach calculation with *** point-wise cross sections and the average resonance parameters showed fair agreement with the evaluated values of the ENDF/B-Ⅷ.0 library in the energy region studied.

关键词： ^(169)Tm(n,γ)^(170)Tm reaction capture cross section PHWT CSNS Back-n white neutron source

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Study of background from accidental coincidence signals in the PandaX-Ⅱexperiment

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Chinese physics C 2022年第10期46卷 11-24页

作者： Abdusalam Abdukerim Wei Chen Xun Chen Yunhua Chen Chen Cheng Xiangyi Cui Yingjie Fan Deqing Fang Changbo Fu Mengting Fu Lisheng Geng Karl Giboni Linhui Gu Xuyuan Guo Ke Han Changda He Di Huang Yan Huang Yanlin Huang Zhou Huang Xiangdong Ji Yonglin Ju Shuaijie Li Huaxuan Liu Jianglai Liu Wenbo Ma Yugang Ma Yajun Mao Yue Meng Kaixiang Ni Jinhua Ning Xuyang Ning Xiangxiang Ren Changsong Shang Lin Si Guofang Shen Andi Tan Anqing Wang Hongwei Wang Meng Wang Qiuhong Wang Siguang Wang Wei Wang Xiuli Wang Zhou Wang Mengmeng Wu Shiyong Wu Weihao Wu Jingkai Xia Mengjiao Xiao Pengwei Xie Binbin Yan Jijun Yang Yong Yang Chunxu Yu Jumin Yuan Ying Yuan Xinning Zeng Dan Zhang Tao Zhang Li Zhao Qibin Zheng Jifang Zhou Ning Zhou Xiaopeng Zhou School of Physics and Astronomy Shanghai Jiao Tong UniversityMOE Key Laboratory for Particle Astrophysics and CosmologyShanghai Key Laboratory for Particle Physics and CosmologyShanghai 200240China Shanghai Jiao Tong University Sichuan Research Institute Chengdu 610213China Yalong River Hydropower Development Company Ltd.288 Shuanglin RoadChengdu 610051China School of Physics Sun Yat-Sen UniversityGuangzhou 510275China Tsung-Dao Lee Institute Shanghai 200240China School of Physics Nankai UniversityTianjin 300071China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China School of Physics Peking UniversityBeijing 100871China School of Physics Beihang UniversityBeijing 102206China Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang UniversityBeijing102206China School of Physics and Microelectronics Zhengzhou UniversityZhengzhouHenan 450001China School of Medical Instrument and Food Engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of Physics University of MarylandCollege ParkMaryland 20742USA School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Physics and Key Laboratory of Particle Physics and Particle Irradiation(MOE) Shandong UniversityJinan 250100China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Center for High Energy Physics Peking UniversityBeijing 100871China

Ⅰ.INTRODUCTION The direct detection of dark matter particles,especially the weakly interacting massive particles(WIMPs),is being actively carried out by a couple of experiments worldwide[1].In recent years,the PandaX-Ⅱ experiment located in the China Jinping Underground Laboratory(CJPL)[1-3],which uses the technology of dual phase liquid xenon time projection chambers(TPCs),has pushed the limits of the cross section between WIMPs and nucleons to a new level for most of the possible WIMP masses;other experiments of the same type are also being performed[4–10].

关键词： dark matter xenon detector background accidental coincidence machine learning

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Dark gauge-mediated supersymmetry breaking with a massless dark photon

arXiv

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arXiv 2024年

作者： Batell, Brian Kim, Yechan Lee, Hye-Sung Lee, Jiheon Pittsburgh Particle Physics Astrophysics and Cosmology Center Department of Physics and Astronomy University of Pittsburgh PittsburghPA15217 United States Department of Physics Korea Advanced Institute of Science and Technology Daejeon34141 Korea Republic of Theoretical Physics Department CERN 1 Esplanade des Particules Geneva 23CH-1211 Switzerland

We study dark gauge-mediated supersymmetry breaking (dark GMSB) in a theory with a new unbroken U(1)D local symmetry and massless dark photon. Messenger fields charged under both Standard Model and dark gauge symmetries produce new soft supersymmetry-breaking terms due to gauge kinetic mixing between U(1)Y hypercharge and U(1)D. We show that large kinetic mixing induces significant distortions to the superpartner spectra relative to conventional GMSB. Notably, shifts in the Higgs soft masses impact the conditions for electroweak symmetry breaking, lowering the µ parameter and yielding a relatively light Higgsino that may be accessible at the LHC. Furthermore, for very simple messenger representations, a very light bino-dark photino mixed state is present in the spectrum, which may be probed through exotic Higgs boson decays at future Higgs factories. We also examine the cosmological and phenomenological consequences of the messengers, the lightest of which is absolutely stable and carries fractional electric charge. Copyright © 2024, The Authors. All rights reserved.

关键词： Photons

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SHAM-OT: Rapid Subhalo Abundance Matching with Optimal Transport

arXiv

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arXiv 2025年

作者： Fischbacher, Silvan Kacprzak, Tomasz Valle, Luis Fernando Machado Poletti Refregier, Alexandre Institute for Particle Physics and Astrophysics ETH Zürich Wolfgang-Pauli-Strasse 27 ZürichCH-8093 Switzerland Swiss Data Science Center Paul Scherrer Institute Forschungsstrasse 111 Villigen5232 Switzerland

Subhalo abundance matching (SHAM) is widely used for connecting galaxies to dark matter haloes. In SHAM, galaxies and (sub-)haloes are sorted according to their mass (or mass proxy) and matched by their rank order. In this work, we show that SHAM is the solution of the optimal transport (OT) problem on empirical distributions (samples or catalogues) for any metric transport cost function. In the limit of large number of samples, it converges to the solution of the OT problem between continuous distributions. We propose SHAM-OT: a formulation of abundance matching where the halo-galaxy relation is obtained as the optimal transport plan between galaxy and halo mass functions. By working directly on these (discretized) functions, SHAM-OT eliminates the need for sampling or sorting and is solved using efficient OT algorithms at negligible compute and memory cost. Scatter in the galaxy-halo relation can be naturally incorporated through regularization of the transport plan. SHAM-OT can easily be generalized to multiple marginal distributions. We validate our method using analytical tests with varying cosmology and luminosity function parameters, and on simulated halo catalogues. The efficiency of SHAM-OT makes it particularly advantageous for Bayesian inference that requires marginalization over stellar mass or luminosity function uncertainties. © 2025, CC BY.

关键词： Cost functions

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Finite Bubble Statistics Constrain Late Cosmological Phase Transitions

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Physical Review Letters 2024年第21期133卷 211003-211003页

作者： Gilly Elor Ryusuke Jinno Soubhik Kumar Robert McGehee Yuhsin Tsai Weinberg Institute Department of Physics University of Texas at Austin Austin Texas 78712 USA Research Center for the Early Universe (RESCEU) Graduate School of Science The University of Tokyo Tokyo 113-0033 Japan Department of Physics Graduate School of Science Kobe University 1-1 Rokkodai Kobe Hyogo 657-8501 Japan Center for Cosmology and Particle Physics Department of Physics New York University New York New York 10003 USA Berkeley Center for Theoretical Physics Department of Physics University of California Berkeley California 94720 USA Theoretical Physics Group Lawrence Berkeley National Laboratory Berkeley California 94720 USA William I. Fine Theoretical Physics Institute School of Physics and Astronomy University of Minnesota Minneapolis Minnesota 55455 USA Leinweber Center for Theoretical Physics Department of Physics University of Michigan Ann Arbor Michigan 48109 USA Department of Physics University of Notre Dame Indiana 46556 USA

We consider first order cosmological phase transitions (PTs) happening at late times below standard model temperatures TPT≲GeV. The inherently stochastic nature of bubble nucleation and the finite number of bubbles associated with a late-time PT lead to superhorizon fluctuations in the PT completion time. We compute how such fluctuations eventually source curvature fluctuations with universal properties, independent of the microphysics of the PT dynamics. Using cosmic microwave background (CMB) and large scale structure measurements, we constrain the energy released in a dark-sector PT. For 0.1 eV≲TPT≲keV this constraint is stronger than both the current bound from additional neutrino species ΔNeff, and in some cases, even CMB-S4 projections. Future measurements of CMB spectral distortions and pulsar timing arrays will also provide competitive sensitivity for keV≲TPT≲GeV.

关键词： Cosmic microwave background First order phase transitions Large scale structure of the Universe

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Constraining self-interacting dark matter with the full dataset of PandaX-II

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science China(physics,Mechanics & Astronomy) 2021年第11期64卷 2-7页

作者： Jijun Yang Abdusalam Abdukerim Wei Chen Xun Chen Yunhua Chen Chen Cheng Xiangyi Cui Yingjie Fan Deqing Fang Changbo Fu Mengting Fu Lisheng Geng Karl Giboni Linhui Gu Xuyuan Guo Ke Han Changda He Shengming He Di Huang Yan Huang Ran Huo Yanlin Huang Zhou Huang Xiangdong Ji Yonglin Ju Shuaijie Li Qing Lin Huaxuan Liu Jianglai Liu Xiaoying Lu Wenbo Ma Yugang Ma Yajun Mao Yue Meng Nasir Shaheed Kaixiang Ni Jinhua Ning Xuyang Ning Xiangxiang Ren Changsong Shang Guofang Shen Lin Si Andi Tan Anqing Wang Hongwei Wang Meng Wang QiuHong Wang Siguang Wang Wei Wang Xiuli Wang Zhou Wang Mengmeng Wu Shiyong Wu Weihao Wu Jingkai Xia Mengjiao Xiao Xiang Xiao Pengwei Xie Binbin Yan Yong Yang Chunxu Yu Hai-Bo Yu Jumin Yuan Ying Yuan Xinning Zeng Dan Zhang Tao Zhang Li Zhao Qibin Zheng Jifang Zhou Ning Zhou Xiaopeng Zhou School of Physics and Astronomy Shanghai Jiao Tong UniversityMOE Key Laboratory for Particle Astrophysics and CosmologyShanghai Key Laboratory for Particle Physics and CosmologyShanghai 200240China Shanghai Jiao Tong University Sichuan Research Institude Chengdu 610213China Yalong River Hydropower Development Company Ltd.Chengdu 610051China School of Physics Sun Yat-sen UniversityGaungzhou 510275China Tsung-Dao Lee Institute Shanghai 200240China School of Physics Nankai UniversityTianjin 300071China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China School of Physics Peking UniversityBeijing 100871China School of Physics Beihang UniversityBeijing 100191China International Research Center for Nuclei and Particles in the Cosmos&Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang UniversityBeijing 100191China Shandong Institute of Advanced Technology Jinan 250103China School of Medical Instrument and Food Engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of Physics University of MarylandCollege ParkMaryland 20742USA School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Key Laboratory of Particle Physics and Particle Irradiation of Ministry of Education Shandong UniversityJinan 250100China Research Center for Particle Science and Technology Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Department of Physics and Astronomy University of CaliforniaRiversideCalifornia 92507USA Center of High Energy Physics Peking UniversityBeijing 100871China

Self-interacting dark matter(SIDM)is a leading candidate proposed to solve discrepancies between predictions of the prevailing cold dark matter theory and observations of *** SIDM models predict the existence of a light force carrier that mediates strong dark matter *** the mediator couples to the standard model particles,it could produce characteristic signals in dark matter direct detection *** report searches for signals of SIDM models with a light mediator using the full dataset of the PandaX-II experiment,basing on a total exposure of 132 *** significant excess over background is found,and our likelihood analysis leads to a strong upper limit on the dark matter-nucleon coupling *** further combine the PandaX-II constraints and those from observations of the light element abundances in the early universe,and show that direct detection and cosmological probes can provide complementary constraints on dark matter models with a light mediator.

关键词： dark matter direct detection self-interacting dark matter

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Exploring the impact of high-precision top-quark pair production data on the structure of the proton at the LHC

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Physical Review D 2024年第5期109卷 054027-054027页

作者： Alim Ablat Marco Guzzi Keping Xie Sayipjamal Dulat Tie-Jiun Hou Ibrahim Sitiwaldi C.-P. Yuan School of Physics Science and Technology Xinjiang University Urumqi Xinjiang 830046 China Department of Physics Kennesaw State University Kennesaw Georgia 30144 USA Pittsburgh Particle Physics Astrophysics and Cosmology Center Department of Physics and Astronomy University of Pittsburgh Pittsburgh Pennsylvania 15260 USA School of Nuclear Science and Technology University of South China Hengyang Hunan 421001 China Department of Physics and Astronomy Michigan State University East Lansing Michigan 48824 USA

The impact of recent LHC top-quark pair production single differential cross section measurements at 13 TeV collision energy on the structure of the proton is explored. In particular, the impact of these high-precision data on the gluon and other parton distribution functions (PDFs) of the proton at intermediate and large partonic momentum fraction x is analyzed. This study extends the CT18 global analysis framework to include these new data. The interplay between top-quark pair and inclusive jet production as well as other processes at the LHC, is studied. In addition, a study of the impact of scale choice on the theory description of the new 13 TeV tt¯ measurements is performed.

关键词： Phenomenology Quantum chromodynamics

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Enhanced Curvature Perturbation and Primordial Black Hole Formation in Two-stage Inflation with a break

arXiv

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arXiv 2024年

作者： Wang, Xinpeng Zhang, Ying-Li Sasaki, Misao School of Physics Science and Engineering Tongji University Shanghai200092 China Institute for Advanced Study of Tongji University Shanghai200092 China Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China The University of Tokyo Institutes for Advanced Study The University of Tokyo Chiba277-8583 Japan Center for Gravitation and Cosmology Yangzhou University Yangzhou225009 China Center for Gravitational Physics and Quantum Information Yukawa Institute for Theoretical Physics Kyoto University Kyoto606-8502 Japan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei10617 Taiwan

We investigate a model of R2-gravity with a non-minimally coupled scalar field that gives rise to two-stage inflation with a break, that is, with an intermediate stage where inflation momentarily halts. We find that the power spectrum of the primordial curvature perturbation is significantly enhanced at the break scale, which can account for the primordial black hole (PBH) formation, without affecting the CMB constraint on large scales. The behavior of the curvature perturbation is carefully analyzed and we find a few notable new features in the spectrum. In particular, we find that the k3 growth of the spectrum of toward the end of the first stage of inflation. We argue that this is a universal feature common to all two-stage models where the field dominating the second stage is heavy during the first stage. By appropriately tuning the model parameters, we find that our model can realize the scenario of PBHs as the cold dark matter of the Universe. We also find that we can choose the parameters so that the spectrum of the induced gravitational waves from the enhanced curvature perturbation fits the NANOGrav-15yr data of pulsar timing array observation. Copyright © 2024, The Authors. All rights reserved.

关键词： Black holes

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