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Variations of secondary particle arrival time detected by LHAASO-KM2A during thunderstorms 38

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Variations of secondary particle arrival time detected by LH...

38th International Cosmic Ray Conference, ICRC 2023

作者： Chen, Xuejian Zhou, Xunxiu Yang, Ci Huang, Daihui Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, J.T. Cao, Q. Cao, W.Y. Cao, Zhe Chang, J. Chang, J.F. Chen, A.M. Chen, E.S. Chen, Liang Chen, Lin Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, Y. Cheng, N. Cheng, Y.D. Cui, M.Y. Cui, S.W. Cui, X.H. Cui, Y.D. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu della Volpe, D. Dong, X.Q. Duan, K.K. Fan, J.H. Fan, Y.Z. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Gabici, S. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Giacinti, G. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, J.Y. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, B.W. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S.C. Huang, D.H. Huang, T.Q. Huang, W.J. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Ji, X.L. Jia, H.Y. Jia, K. Jiang, K. Jiang, X.W. Jiang, Z.J. Jin, M. Kang, M.M. Ke, T. Kuleshov, D. Kurinov, K. Li, B.B. Li, Cheng Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li, W.L. 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.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Lu, R. Luo, Q. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Min, Z. Mitthumsiri, W. Mu, H.J. Nan, Y.C. Neronov, A. 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. Semikoz, D. Shao, C.Y. Shao, L. Shchegolev, O. Sheng, X.D. Shu, F.W. Song, H.C. Stenkin, Yu.V. Stepanov, V. Su, Y. Sun, Q.N. Sun, X.N. School of Physical Science and Technology Southwest Jiaotong University Chengdu610031 China 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 Dublin 2 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 School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China Hebei Normal University Hebei Shijiazhuang050024 China Key Laboratory of Dark Matter and Space Astronomy Key Laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Tsung-Dao Lee Institute School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Key Laboratory of Cosmic Rays Tibet University Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Physics and Astronomy Sun Yat-sen University Zhuhai519000 China School of Physics Sun Yat-sen University Guangdong Guangzhou510275 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Zhuhai519000 China School of Physics and Astronomy Yunnan University Yunnan Kunming650091 China Départeme

A sub-array of the Large High Altitude Air Shower Observatory (LHAASO), KM2A contains 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). For each shower event that meets the trigger conditions (at least 20 fired EDs within a time window of 400 ns) in KM2A array, there are many signals from ED and MD detectors. The information on the arrival time and location of each signal are recorded, and the ED hits are used for shower reconstruction. Due to the acceleration and deflection by the atmospheric electric field (AEF) during a thunderstorm, the arrival time and position of the ground-level particles are modified, resulting in the changes in the inferred shower detection. To understand the shower event variation during thunderstorms, the particle arrival time is studied by analyzing the KM2A data. We can measure the distribution of changes of arrival time in the thunderstorm electric field. The variation amplitude is not only dependent on the AEF, but also highly correlated with the direction of the shower event. With the increase of the AEF strength and the zenith angle, the variation in amplitude of the arrival time becomes larger. Our results are useful in understanding the variation of shower rate detected by LHAASO-KM2A, and will also provide important information for shower reconstruction during thunderstorms. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Thunderstorms

Primordial black hole formation from massless scalar isocurvature

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Physical Review D 2022年第10期105卷 103538-103538页

作者： Chul-Moon Yoo Tomohiro Harada Shin’ichi Hirano Hirotada Okawa Misao Sasaki Division of Particle and Astrophysical Science Graduate School of Science Nagoya University Nagoya 464-8602 Japan Department of Physics Rikkyo University Toshima Tokyo 171-8501 Japan Waseda Institute for Advanced Study (WIAS) Waseda University Shinjuku Tokyo 169-0051 Japan Kavli Institute for the Physics and Mathematics of the Universe (WPI) University of Tokyo Kashiwa 277-8583 Japan Center for Gravitational Physics Yukawa Institute for Theoretical Physics Kyoto University Kyoto 606-8502 Japan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei 10617 Taiwan

We numerically study the primordial black hole (PBH) formation by an isocurvature perturbation of a massless scalar field on super Hubble scales in the radiation-dominated Universe. As a first step we perform simulations of spherically symmetric configurations. For the initial condition, we employ the spatial gradient expansion and provide the general form of the growing mode solutions valid up through the second order in this expansion. The initial scalar field profile is assumed to be Gaussian with a characteristic comoving wave number k; ∼exp(−k2R2), where R is the radial coordinate. We find that a PBH is formed for a sufficiently large amplitude of the scalar field profile. Nevertheless, we find that the late time behavior of the gravitational collapse is dominated by the dynamics of the fluid but not by the scalar field, which is analogous to the PBH formation from an adiabatic perturbation in the radiation-dominated Universe.

关键词： Classical black holes Inflation Massive compact halo objects

Nucleon Consumption and Mass-Energy Conversion Induced by Dark Matter

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arXiv 2024年

作者： Ge, Shao-Feng Ma, Xiao-Dong Tsung-Dao Lee Institute School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai Jiao Tong University Shanghai200240 China Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter Institute of Quantum Matter South China Normal University Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Guangdong Provincial Key Laboratory of Nuclear Science Southern Nuclear Science Computing Center South China Normal University Guangzhou510006 China

We propose the nucleon consumption induced by dark matter (DM) as a new scenario to overcome the energy threshold of direct detection. It can be realized with proton (χ + p → χ + +) or neutron (χ + n → χ + ν) target. Both effective operators and concrete models are provided to illustrate the idea. Since the initial DM and nucleon velocity is only 10−3 and 1/4 of the speed of light, respectively, the cross section and hence event rate are determined by the involved particle masses and not affected by the nucleon Fermi motion. Of the two realizations, the proton consumption has richer phenomena with both charged lepton and the daughter nuclei de-excitation to allow double or even triple coincidence to significantly suppress the background. We also illustrate the projected sensitivities at DM and neutrino experiments such as PandaX-4T, DUNE, JUNO, and Hyper-K. Copyright © 2024, The Authors. All rights reserved.

关键词： Dark Matter

Prospects for joint reconstruction of imaging air Cherenkov Telescope array and extensive air shower array

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arXiv 2024年

作者： Zhang, Zhipeng Yang, Ruizhi Zhang, Shoushan Yin, LiQiao Liu, Jiali Wang, Yudong Ma, Lingling Cao, Zhen School of Astronomy Space Science University of Science and Technology of China Anhui Hefei230026 China CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Anhui Hefei230026 China Deep Space Exploration Laboratory School of Physical Sciences University of Science and Technology of China Hefei230026 China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Beijing China Department of Physics University of Chinese Academy of Sciences Beijing China Tianfu Cosmic Ray Research Center Chengdu China

In this paper, we proposed a joint reconstruction of γ-ray events using both extensive air array (EAS) and Imaging air Cherenkov Telescope array (IACT). We considered eight Cherenkov telescopes to be built on the LHAASO (Large High Altitude Air Shower Observatory) site and investigate the improvement in differential sensitivity when combining the information from both IACT and Moun detectors of LHAASO-KM2A. We found that due to the higher cosmic ray background rejection power and higher gamma ray retention ratio provided by muon detectors of LHAASO, such a joint reconstruction can significantly improve the sensitivity of IACTs, especially for extended sources and long exposure time. The sensitivity of the eight-telescopes array can be improved by 25% − 60% in different energy ranges using joint reconstructions with muon detectors. Copyright © 2024, The Authors. All rights reserved.

关键词： Cosmic rays

All-sky three-dimensional dust density and extinction Maps of the Milky Way out to 2.8 kpc

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arXiv 2024年

作者： Dharmawardena, T.E. Bailer-Jones, C.A.L. Fouesneau, M. Foreman-Mackey, D. Coronica, P. Colnaghi, T. Müller, T. Wilson, A.G. Königstuhl 17 Heidelberg69117 Germany Center for Computational Astrophysics Flatiron Institute 162 5th Ave New YorkNY10010 United States Center for Cosmology and Particle Physics Department of Physics New York University 726 Broadway Room 1005 New YorkNY10003 United States Max Planck Computing and Data Facility Gießenbachstraße 2 Garching85748 Germany Courant Institute of Mathematical Sciences New York University 251 Mercer St New YorkNY10012 United States

Three-dimensional dust density maps are crucial for understanding the structure of the interstellar medium of the Milky Way and the processes that shape it. However, constructing these maps requires large datasets and the methods used to analyse them are computationally expensive and difficult to scale up. As a result it is has only recently become possible to map kiloparsec-scale regions of our Galaxy at parsec-scale grid sampling. We present all-sky three-dimensional dust density and extinction maps of the Milky Way out to 2.8 kpc in distance from the Sun using the fast and scalable Gaussian Process algorithm Dustribution. The sampling of the three-dimensional map is l, b, d = 1◦ × 1◦ × 1.7 pc. The input extinction and distance catalogue contains 120 million stars with photometry and astrometry from Gaia DR2, 2MASS and AllWISE. This combines the strengths of optical and infrared data to probe deeper into the dusty regions of the Milky Way. We compare our maps with other published 3D dust maps. All maps quantitatively agree at the 0.001 mag pc−1 scale with many qualitatively similar features, although each map also has its own features. We recover Galactic features previously identified in the literature. Moreover, we also see a large under-density that may correspond to an inter-arm or -spur gap towards the Galactic Centre. © 2024, CC BY.

关键词： Dust

Exploring neutrino mass and mass hierarchy in interacting dark energy models

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science China(physics,Mechanics & Astronomy) 2020年第2期63卷 55-63页

作者： Lu Feng Hai-Li Li Jing-Fei Zhang Xin Zhang College of Physical Science and Technology Shenyang Normal UniversityShenyang 110034China Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Ministry of Education Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern UniversityShenyang 110819China Center for High Energy Physics Peking UniversityBeijing 100080China Center for Gravitation and Cosmology Yangzhou UniversityYangzhou 225009China

We investigate how the dark energy properties impact the constraints on the total neutrino mass in interacting dark energy（IDE）models. In this study, we focus on two typical interacting dynamical dark energy models, i.e., the interacting w cold dark matter（IwCDM） model and the interacting holographic dark energy（IHDE） model. To avoid the large-scale instability problem in IDE models, we apply the parameterized post-Friedmann approach to calculate the perturbation of dark energy. We employ the Planck 2015 cosmic microwave background temperature and polarization data, combined with low-redshift measurements on baryon acoustic oscillation distance scales, type Ia supernovae, and the Hubble constant, to constrain the cosmological parameters. We find that the dark energy properties could influence the constraint limits on the total neutrino mass. Once dynamical dark energy is considered in the IDE models, the upper bounds of ∑mν will be changed. By considering the values of χmin2 , we find that in these IDE models the normal hierarchy case is slightly preferred over the inverted hierarchy case; for example, ?χ2= 2.720 is given in the IHDE+∑mν model. In addition, we also find that in the Iw CDM+∑mν model β = 0 is consistent with current observational data inside the 1σ range, and in the IHDE+∑mν model β > 0 is favored at more than 2σ level.

关键词： neutrino mass mass hierarchies of neutrinos interacting dark energy cosmological observations cosmological constraints

A new method to access heavy meson lightcone distribution amplitudes from first-principle

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arXiv 2024年

作者： Han, Xue-Ying Hua, Jun Ji, Xiangdong Lü, Cai-Dian Wang, Wei Xu, Ji Zhang, Qi-An Zhao, Shuai Institute of High Energy Physics CAS Beijing100049 China School of Physics University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Atomic and Subatomic Structure and Quantum Control MOE Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter Institute of Quantum Matter South China Normal University Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Guangdong Provincial Key Laboratory of Nuclear Science Southern Nuclear Science Computing Center South China Normal University Guangzhou510006 China Department of Physics University of Maryland College ParkMD20742 United States Shanghai Key Laboratory for Particle Physics and Cosmology Key Laboratory for Particle Astrophysics and Cosmology MOE School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Institute of Modern Physics Chinese Academy of Sciences Guangdong Province Huizhou516000 China School of Physics and Microelectronics Zhengzhou University Henan Zhengzhou450001 China School of Physics Beihang University Beijing102206 China Department of Physics Tianjin University Tianjin300350 China

We present a method to compute lightcone distribution amplitudes (LCDAs) of heavy meson within heavy quark effective theory (HQET). Our method utilizes quasi distribution amplitudes (quasi-DAs) with a large momentum component Pz. We point out that by sequentially integrating out Pz and mH, one can disentangle different dynamical scales. Integrating out Pz allows to connect quasi-DAs to QCD LCDAs, and then integrating out mH enables to relate QCD LCDAs to HQET LCDAs. To verify this proposal, we make use of lattice QCD simulation on a lattice ensemble with spacing a = 0.05187 fm. The preliminary findings for HQET LCDAs qualitatively align with phenomenological models. Using a recent model for HQET LCDAs, we also fit the first inverse moment λ−1B and the result is consistent with the experimentally constrain from B → γν. This agreement demonstrates the promise of our method in providing first-principle predictions for heavy meson LCDAs. © 2024, CC BY.

关键词： Hadrons

Probing Zee-Babu states at muon colliders

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Physical Review D 2024年第7期109卷 075011-075011页

作者： Adil Jueid Talal Ahmed Chowdhury Salah Nasri Shaikh Saad Particle Theory and Cosmology Group Center for Theoretical Physics of the Universe Institute for Basic Science (IBS) 34126 Daejeon Republic of Korea Department of Physics University of Dhaka Dhaka 1000 Bangladesh Department of Physics and Astronomy University of Kansas Lawrence Kansas 66045 USA and The Abdus Salam International Centre for Theoretical Physics Strada Costiera 11 I-34014 Trieste Italy Department of Physics UAE University P.O. Box 15551 Al-Ain United Arab Emirates and The Abdus Salam International Centre for Theoretical Physics Strada Costiera 11 I-34014 Trieste Italy Department of Physics University of Basel Klingelbergstrasse 82 CH-4056 Basel Switzerland

The Zee-Babu model is a minimal realization of radiative neutrino mass generation mechanism at the two-loop level. We study the phenomenology of this model at future multi-TeV muon colliders. After imposing all theoretical and low-energy experimental constraints on the model parameters, we find that the Zee-Babu states are expected not to reside below the TeV scale, making it challenging to probe them at the LHC. We first analyze the production rates for various channels, including multi singly charged and/or doubly charged scalars at muon colliders. For concreteness, we study several benchmark points that satisfy neutrino oscillation data and other constraints and find that most channels have large production rates. We then analyze the discovery reach of the model using two specific channels: the pair production of singly and doubly charged scalars. For the phenomenologically viable scenarios considered in this study, charged scalars with masses up to O(3–4) TeV can be probed for the center-of-mass energy of 10 TeV and total luminosity of 10 ab−1.

关键词： Extensions of scalar sector particle interactions Hypothetical scalars Muons Lepton colliders

Simulation study on cosmic ray shower rate variations with LHAASO-KM2A during thunderstorms 38

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Simulation study on cosmic ray shower rate variations with L...

38th International Cosmic Ray Conference, ICRC 2023

作者： Yang, Ci Zhou, Xunxiu Chen, Xuejian Huang, Daihui Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, J.T. Cao, Q. Cao, W.Y. Cao, Zhe Chang, J. Chang, J.F. Chen, A.M. Chen, E.S. Chen, Liang Chen, Lin Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, Y. Cheng, N. Cheng, Y.D. Cui, M.Y. Cui, S.W. Cui, X.H. Cui, Y.D. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu della Volpe, D. Dong, X.Q. Duan, K.K. Fan, J.H. Fan, Y.Z. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Gabici, S. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Giacinti, G. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, J.Y. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, B.W. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S.C. Huang, D.H. Huang, T.Q. Huang, W.J. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Ji, X.L. Jia, H.Y. Jia, K. Jiang, K. Jiang, X.W. Jiang, Z.J. Jin, M. Kang, M.M. Ke, T. Kuleshov, D. Kurinov, K. Li, B.B. Li, Cheng Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li, W.L. 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.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Lu, R. Luo, Q. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Min, Z. Mitthumsiri, W. Mu, H.J. Nan, Y.C. Neronov, A. 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. Semikoz, D. Shao, C.Y. Shao, L. Shchegolev, O. Sheng, X.D. Shu, F.W. Song, H.C. Stenkin, Yu.V. Stepanov, V. Su, Y. Sun, Q.N. Sun, X.N. School of Physical Science and Technology Southwest Jiaotong University Chengdu610031 China 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 Dublin 2 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 School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China Hebei Normal University Hebei Shijiazhuang050024 China Key Laboratory of Dark Matter and Space Astronomy Key Laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Tsung-Dao Lee Institute School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Key Laboratory of Cosmic Rays Tibet University Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Physics and Astronomy Sun Yat-sen University Zhuhai519000 China School of Physics Sun Yat-sen University Guangdong Guangzhou510275 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Zhuhai519000 China School of Physics and Astronomy Yunnan University Yunnan Kunming650091 China Départeme

The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA, and WFCTA. As the major array of LHAASO, KM2A has been operating stably in shower mode. To study the near-earth atmospheric electric field (AEF) effect on the trigger event rate during thunderstorms, Monte Carlo simulations are performed with CORSIKA and G4KM2A. According to the simulations, the shower rate variations are found to be strongly dependent on the strength and polarity of the AEF. The shower rates increase with the field intensity. In positive AEF (defined as the direction pointing towards the ground), the increased amplitude is less than that in negative AEF. With the same field strength 1000 V/cm, the value exceeds 12% in a negative field, and merely is up to 6% in the positive one. The dependence of the trigger rate variation on the thickness of the AEF layer is also simulated. The shower event rate increases dramatically at small thickness, and then the trend of variation slows down with the AEF layer thickness. This indicates that the AEF with larger layer thickness has more deflection effects on the development of an extensive air shower. The shower rate variations are also found to be dependent on the primary zenith angle. Our simulation results could be useful in understanding the variation of trigger rate detected by LHAASO-KM2A during thunderstorms. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： cosmology