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7th International particle Accelerator Conference, IPAC 2016

作者： Jiao, Y. Xu, G. Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Beijing100049 China

ISBN: (纸本)9783954501472

The High Energy Photon Source (HEPS), a kilometrescale diffraction-limited storage ring (DLSR) light source, with a beam energy of 5 to 6 GeV and transverse emittances of a few tens of ***, is to be built in Beijing. We have obtained a hybrid 7BA lattice design, with a natural emittance of about 60 *** and a circumference of about 1.3 kilometres, basically satisfying the requirement of on-axis longitudinal injection in HEPS. Nevertheless, it is interesting and necessary to explore the ultimate linear and nonlinear performance of the HEPS hybrid 7BA design. In this paper, we will introduce the multiobjective optimization with a successive and iterative implementation of the MOPSO and MOGA algorithms, and discuss certain relations between the nonlinear dynamics and linear optics of a hybrid MBA lattice. This study can provide reference for other DLSR lattice design and optimizations. Copyright © 2016 CC-BY-3.0 and by the respective authors.

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Development of the impedance model in HEPS 8

Development of the impedance model in HEPS

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8th International particle Accelerator Conference, IPAC 2017

作者： Wang, N. Tian, S.K. Li, X.Y. Xu, G. Duan, Z. Shi, H. Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Beijing100049 China

ISBN: (纸本)9783954501823

The High Energy Photon Source (HEPS) is a new designed photon source at beam energy of 6 GeV. Due to the small beam pipe aperture and a large number of insertion devices in the machine, the impedance can drive collective instabilities and limit the machine performance. Therefore, a thorough estimation of the coupling impedance is necessary in controlling the total impedance of the whole machine. A primary impedance model is obtained for the storage ring. © 2017 CC-BY-3.0 and by the respective authors

关键词： Photons

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Preliminary study on IPM for CADS injector I 6

Preliminary study on IPM for CADS injector I

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6th International Beam Instrumentation Conference, IBIC 2017

作者： He, J. Wang, Z.Z. Zhou, J.S. Sui, Y.F. Yue, J.H. Cao, J.S. Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Beijing100049 China

ISBN: (纸本)9783954501922

The Ionization Profile Monitor (IPM) based on the residual gas molecule is designed and fabricated for high power proton beam accelerator China Accelerator Driven Subcritical system injector I. The method of calculating the intensity of ionization signal is explored. The device uses the electric field generated by electrode to guide the ions, using Microchannel plates (MCP) to amplify ionization signals. A screen and a camera is used to detect the output electrons of the MCP, which present the distribution of the beam. The electric field distribution is optimized by CST ELECTROMAGNETIC STUDIO calculation. The IPM is installed on the ADS injector I and tested by beam. It measures the proton profile successfully during the CW commission. The experiment results agree well with the theoretical value which proves that the equipment can be used for CADS main linac in future. © 2018 by JACoW - cc Creative Commons Attribution 3.0.

关键词： Ionization of gases

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Searching for Nearby Diffuse Dwarf Galaxies in the COSMOS Field

arXiv

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arXiv 2025年

作者： Shi, DongDong Zheng, XianZhong Pan, Zhizheng Luo, Yu Deng, Hongxia Hua, Qunzhi Luo, Xinyu Wu, Qiming Center for Fundamental Physics School of Mechanics and Optoelectronic Physics Anhui University of Science and Technology Huainan232001 China Tsung-Dao Lee Institute Key Laboratory for Particle Physics Astrophysics and Cosmology Ministry of Education Shanghai Jiao Tong University Shanghai201210 China Purple Mountain Observatory Chinese Academy of Sciences 10 Yuan Hua Road Jiangsu Nanjing210023 China Department of Physics School of Physics and Electronics Hunan Normal University Changsha410081 China

It remains challenging to systematically survey nearby diffuse dwarf galaxies and address the formation mechanism of this population distinguishing from regular ones. We carry out a pilot search for these galaxies in the COSMOS field using the deep HST/F814W imaging data. We report three diffuse dwarf galaxies satisfying the criteria: (1) redshift z e > 1′′ . 0, and (3) central surface brightness µ0 > 24 mag arcsec−2. Two of the three galaxies, COSMOS-UDG1 and COSMOS-UDG2, are recognized as ultra-diffuse galaxies (UDGs) with redshift z = 0.130 and 0.049, respectively. The third galaxy, COSMOS-dw1, is spectroscopically confirmed as a dwarf galaxy at z = 0.004. We derive the physical properties through fitting their spectral energy distributions (SEDs) extracted from deep multiwavelength observations. COSMOS-dw1 has a stellar mass of 5.6+2−2.57 × 106 M☉, harboring neutral hydrogen gas of mass 4.90 ± 0.90 × 106 M☉, hinting that this galaxy may be in the nascent stages of quenching. The estimated dynamical mass of 3.4 × 107 M☉ further suggests that COSMOS-dw1 is predominantly of dark matter. COSMOS-UDG1 and COSMOS-UDG2 exhibit comparable stellar masses of ∼ 2 × 108 M☉. Notably, COSMOS-UDG1 is younger and more metal-rich than COSMOS-UDG2 and COSMOS-dw1. Conversely, COSMOS-UDG2 and COSMOS-dw1 have similar stellar metallicities, yet COSMOS-UDG2 is older than COSMOS-dw1. All three galaxies adhere to the stellar mass-metallicity relation (MZR) for dwarf galaxies in the local Universe, implying they belong to the dwarf galaxy population. © 2025, CC BY.

关键词： Stars

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Feasibility study of online tuning of the luminosity in a circular collider with the robust conjugate direction search method

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Chinese physics C 2015年第12期39卷 89-94页

作者：纪红飞焦毅王生季大恒于程辉张源黄小彪 Dongguan Institute of Neutron Science(DINS) Institute of High Energy Physics Chinese Academy of Sciences Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of Sciences SLAC National Accelerator Laboratory

The robust conjugate direction search （RCDS） method has high tolerance to noise in beam experiments. It has been demonstrated that this method can be used to optimize the machine performance of a light source online. In our study, taking BEPCII as an example, the feasibility of online tuning of the luminosity in a circular collider is explored, through numerical simulation and preliminary online experiments. It is shown that the luminosity that is artificially decreased by a deviation of beam orbital offset from optimal trajectory can be recovered with this method.

关键词： online RCDS luminosity multivariable function

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Effects of insertion devices on stored electron beam of high energy photon source 8

Effects of insertion devices on stored electron beam of high...

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8th International particle Accelerator Conference, IPAC 2017

作者： Li, X.Y. Ji, D.H. Jiao, Y. Duan, Z. Yang, Y.F. Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Beijing100049 China

ISBN: (纸本)9783954501823

The High Energy Photon Source (HEPS) is a 4th generation, 6-Gev, ultralow-emittance, photon source project in China. High brightness hard X-ray beams at the energy particularly above 10kev are provided by insertion devices installed in straight sections of the storage ring. Brightness tuning curves of 14 ID beamlines planned in HEPS first stage are obtained after designing their parameters. However the presence of these insertion devices produce several effects on the beam performances including betatron tunes, betatron amplitude functions, closed orbit, emittance and dynamic aperture etc. It is found that the vertical octupole effect due to the fourteen IDs under the present schemes produce the most significant effect on the vertical dynamic aperture reduction. The ID field error effects on close orbit can be completely compensated by two correctors adjacent the ID at the both side. The horizontal emittance reduces to *** due to the damping wiggler effect of IDs with field error after the orbit correction is also obtained. © 2017 CC-BY-3.0 and by the respective authors

关键词： Photons

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Overview of beam instrumentation for the CADS injector I proton linac 6

Overview of beam instrumentation for the CADS injector I pro...

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6th International particle Accelerator Conference, IPAC 2015

作者： Sui, Y.F. Cao, J.S. Ma, H.Z. Yu, L.D. Zhao, Y. Deng, Q.Y. He, J. Zhao, X.Y. Ye, Q. Yue, J.H. Wang, L. Key Laboratory of Particle Acceleration Physics and Technology IHEP Chinese Academy of Sciences 100049 China

ISBN: (纸本)9783954501687

The injector I of China Accelerator Driven Subcritical system (C-ADS), which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the beam energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam energy as well as beam current and beam losses. Though many of that are conventional design, they can provide efficient operation of injector linac. This paper gives an overview of C-ADS linac beam instrumentation. Copyright © 2015 CC-BY-3.0 and by the respective authors.

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Recent physical studies for the HEPS project 7

Recent physical studies for the HEPS project

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7th International particle Accelerator Conference, IPAC 2016

作者： Xu, G. Duan, Z. Guo, Y.Y. Ji, D.H. Jiao, Y. Li, X.Y. Peng, Y.M. Qin, Q. Qiu, J. Tian, S.K. Wang, J.Q. Wang, N. Wei, Y.Y. Yu, C.H. Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Beijing100049 China

ISBN: (纸本)9783954501472

The High Energy Photon Source (HEPS), a kilometrescale storage ring light source, with a beam energy of 5 to 6 GeV and transverse emittances of a few tens of ***, is to be built in Beijing and now is under design. In this paper we reported the progress and status of the physical studies for the HEPS project, covering issues of storage lattice design and optimization, booster design, injection design, collective effects, error study, insertion device effects, longitudinal dynamics, etc. Copyright © 2016 CC-BY-3.0 and by the respective authors.

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Status and prospect of weak radiative hyperon decays

arXiv

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arXiv 2025年

作者： Shi, Rui-Xiang Jia, Zekun Geng, Li-Sheng Peng, Haiping Zhao, Qiang Zhou, Xiaorong Department of Physics Guangxi Normal University Guilin541004 China Guangxi Key Laboratory of Nuclear Physics and Technology Guilin541004 China University of Science and Technology of China Hefei230026 China State Key Laboratory of Particle Detection and Electronics Hefei230026 China School of Physics Beihang University Beijing102206 China Centrale Pekin Beihang University Beijing100191 China Peng Huanwu Collaborative Center for Research and Education Beihang University Beijing100191 China Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University Beijing102206 China Institute of Modern Physics Chinese Academy of Sciences Huizhou516000 China Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China Center for High Energy Physics Henan Academy of Sciences Zhengzhou450046 China

Weak radiative hyperon decays represent a rich interplay between weak interactions and the internal structure of baryons, offering profound insights into Quantum Chromodynamics and weak interactions. Recent experimental observations, particularly from BESIII, have revealed deviations from theoretical predictions. These deviations could signal new physics or the need for refined theoretical models incorporating intermediate resonance effects. This review discusses recent theoretical advancements and key experimental findings, focusing on recent measurements from BESIII and their implications for strong interactions and baryon structure. Copyright © 2025, The Authors. All rights reserved.

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Embers of Active Galactic Nuclei: Tidal Disruption Events and Quasiperiodic Eruptions

arXiv

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arXiv 2025年

作者： Jiang, Ning Pan, Zhen CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei230026 China School of Astronomy and Space Sciences University of Science and Technology of China Hefei230026 China Tsung-Dao Lee Institute Shanghai Jiao-Tong University 520 Shengrong Road Shanghai201210 China School of Physics & Astronomy Shanghai Jiao-Tong University 800 Dongchuan Road Shanghai200240 China Shanghai Key Laboratory for Particle Physics and Cosmology 800 Dongchuan Road Shanghai200240 China

Recent observations have confirmed the direct association between tidal disruption events (TDEs) and quasiperiodic eruptions (QPEs). In addition, TDE hosts and QPE hosts are statistically found to be similar in their morphological properties and in the strong overrepresentation of poststarburst galaxies. Particularly, both of them show an intriguing preference for extending emission line regions (EELRs), which are indicative of recently faded active galactic nuclei (AGNs). This further suggests that QPEs might be produced following TDEs involving supermassive black holes at a particular stage, when the AGN activity has recently ceased. Moreover, in the framework of "QPEs=extreme mass ratio inspiral (EMRI) + accretion disk" model, a large fraction of QPE EMRIs are inferred to be quasi-circular from the QPE timing, indicating that they are wet EMRIs that were formed in the AGN disk during a previous AGN phase. Based on these facts, we propose a unified scenario that connects these three phenomena: AGN activities boost both the TDE rate and the formation rate of low-eccentricity EMRIs, consequently TDEs are preferentially found in recently faded AGNs instead of in ongoing AGNs due to selection effects, and QPEs are also preferentially found in recently faded AGNs where TDEs frequently feed a misaligned accretion disk to the EMRI. Copyright © 2025, The Authors. All rights reserved.

关键词： Active Galactic Nuclei

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