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electromagnetic form factors of neutron and neutral hyperons in the oscillating point of view

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Chinese Physics C 2022年第7期46卷 41-46页

作者： An-Xin Dai Zhong-Yi Li Lei Chang Ju-Jun Xie Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000 China School of Nuclear Science and Technology University of Chinese Aeademy of SciencesBeijing 101408China School of Physics Nankai UniversityTijin 300071China School of Physics and Microelectronics Zhengzhou UniversityZhengzhouHenan 450001China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu ProvinceLanzhou UniversityLanzhou 730000China

Based on the recent precise measurements by the BESIII collaboration for electron–positron annihilation into a neutron and antineutron pair,the effective form factors of the neutron were determined in the time-like region,and it was found that the effective form factors of the neutron are smaller than those of the *** effective form factors of the neutron show a periodic behaviour,similar to those of the ***,a comparative analysis forΛ,∑^(0)and■hyperons is *** of the available data on the effective form factors ofΛ,∑^(0)and■with zero charge show an interesting phenomenon in the oscillating behavior of their effective form ***,this will need to be confirmed by future precise *** theoretical and experimental investigations of this phenomenon can shed light on the reaction mechanisms of the electron–positron annihilation processes.

关键词： electromagnetic form factors baryon-antibaryon pair production electron-positron annihilation

electromagnetic form factors of Σ^(+) and Σ^(-) in the vector-meson dominance model

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Communications in Theoretical Physics 2021年第5期73卷 66-70页

作者： Zhong-Yi Li Ju-Jun Xie Institute of Modem Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 101408China School of Physics and Microelectronics Zhengzhou UniversityZhengzhouHenan 450001China

Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) and Σ^(-) in the timelike region are investigated using the vector-meson dominance model,where the contributions of theρ,ω,and φ mesons are taken into *** model parameters are determined from the BESⅢexperimental data of the timelike effective form factors|G_(eff)|of the Σ^(+) and Σ^(-) baryons for center-of-mass energies from 2.3864 to 3.02 *** is found that we can provide quantitative descriptions of the available data using as few as one adjustable model *** then progress to an analysis of the electromagnetic form factors in the spacelike region and evaluate the spacelike form factors of the hyperons Σ^(+) and Σ^(-).The electromagnetic form factors obtained for the Σ^(+) and Σ^(-) baryons are comparable with those of other model calculations.

关键词： electromagnetic form factors Vector-meson dominance Hyperon–antihyperon pair production

Deuteron electromagnetic form factors and tensor polarization observables in the framework of the hard-wall AdS/QCD model

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Chinese Physics C 2023年第1期47卷 55-62页

作者： Narmin Huseynova Shahin Mamedov Jannat Samadov Institute for Physical Problems Baku State UniversityZ.Khalilov 23BakuAZ-1148Azerbaijan Institute of Physics Azerbajan National Academy of SciencesH.Javid 33BakuAZ 1143Azerbajan Shamakhy Astrophysical Observatory Azerbajan National Academy of SciencesH.Javid 115BakuAZ 1000Azerbaijan

We study the electromagnetic form factors and tensor polarization observables of the deuteron in the framework of the hard-wall AdS/QCD *** find a profile function for the bulk twistτ=6 vector field,which describes the deuteron on the boundary and fix the infrared boundary cut-off of AdS space in accordance with the ground state mass of the *** obtain the deuteron charge monopole,quadrupole,and magnetic dipole form factors and tensor polarization observables from the bulk Lagrangians for the deuteron and photon field *** plot the momentum transfer dependence of the form factors and tensor polarization observables and compare our numerical results with those in the soft-wall model and experimental data.

关键词： deuteron electromagnetic form factors structure functions tensor polarization observables hard-wall model

Excited nucleon electromagnetic form factors from broken spin-flavor symmetry

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Chinese Physics C 2009年第12期33卷 1257-1260页

作者： A. J. Buchmann Institute for Theoretical Physics University of Tbingen Tbingen D-72076 Germany

A group theoretical derivation of a relation between the N→△charge quadrupole transition and neutron charge form factors is presented.

关键词： electromagnetic form factors group theory spin-flavor symmetry symmetry breaking

Deuteron electromagnetic form factors in transverse plane with a phenomenological Lagrangian approach

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Chinese Physics C 2014年第7期38卷 50-58页

作者：梁翠英董宇兵梁伟红 Institute of High Energy Physics Chinese Academy of Sciences Theoretical Physics Center for Science Facilities (TPCSF) Chinese Academy of Sciences College of Physical Science and Technology Guangxi Normal University

A phenomenological Lagrangian approach is employed to study the electromagnetic properties of deuteron The deuteron is regarded as a loosely bound state of a proton and a neutron. The deuteron electromagnetic form factors are expressed in light-front representation in the transverse plane. The transverse charge density of the deuteron is discussed.

关键词： deuteron nucleon electromagnetic form factors transverse plane impact parameter space

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核子电磁形状因子振荡行为的新视角

Science Bulletin 2023年第22期68卷 2729-2733,M0005页

作者：杨勤鹤郭棣戴凌云 Johann Haidenbauer 康现伟 Ulf-GMeiner School of Physics and Electronics Hunan UniversityChangsha 410082China Hunan Provincial Key Laboratory of High-Energy Scale Physics and Applications Hunan UniversityChangsha 410082China Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichJülich D-52425Germany Key Laboratory of Beam Technology of the Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China Helmholtz Institut für Strahlen-und Kernphysik and Bethe Center for Theoretical Physics Universität BonnBonn D-53115Germany Tbilisi State University Tbilisi 0186Georgia

本文研究了质子和中子的类时电磁形状因子.作者基于手征有效场论,通过求解李普曼-施温格方程得到了核子-反核子对散射振幅.以此为输入,利用扭曲波恩近似方法描述了核子末态相互作用,计算了正负电子湮灭到正反核子对的过程.通过拟合相移... 详细信息

本文研究了质子和中子的类时电磁形状因子.作者基于手征有效场论,通过求解李普曼-施温格方程得到了核子-反核子对散射振幅.以此为输入,利用扭曲波恩近似方法描述了核子末态相互作用,计算了正负电子湮灭到正反核子对的过程.通过拟合相移、截面以及微分截面等实验数据,定下了有效场论的未知耦合常数.进一步研究发现,可以利用两个分数振荡振子来描述核子电磁类时形状因子的振荡行为:一个表现为过阻尼振荡,在阈值附近占主导地位;另一个类似于欠阻尼振荡,在高能区起到重要作用.这种振荡行为对理解硬光子诱导的核子内部极化电荷的分布起着至关重要的作用.

关键词： electromagnetic form factors Fractional oscillator Chiral effective field theory Lippmann-Schwinger equation Distorted wave Born approximation

Recent results on nucleon resonance electrocouplings from the studies of π^+π^-p electroproduction with the CLAS detector

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Chinese Physics C 2009年第12期33卷 1210-1215页

作者： V. I. Mokeev V. D. Burkert L. Elouadrhiri G. V. Fedotov E. N. Golovach B. S. Ishkhanov Jefferson Lab Newport News 12000 Jefferson Ave VA 23606 USA Skobeltsyn Nuclear Physics Institute at Moscow State University Moscow 119899 Russia Physics Department at Moscow State University Moscow 119899 Russia

Recent results on nucleon resonance studies in π＋π-p electro- production off protons with the CLAS detector are presented. The analysis of CLAS data allowed us to determine all essential contributiag mechanisms, providing a credible separation between resonant and non-resonant parts of the cross sections in a wide kinematical area of invariant masses of the final hadronic system 1.3 〈 W 〈 1.8 GeV and photon virtutualities 0.2 〈 Q2 〈 1.5 GeV2. Electrocouplings of several excited proton states with masses less than 1.8 GeV were obtained for the first time from the analysis of π＋π-p exclusive electroproduction channel.

关键词： nucleon resonances electromagnetic form factors nucleon structure

Time-like proton form factor measurement with ANDA

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Chinese Physics C 2009年第12期33卷 1244-1248页

作者： M. Sudol Institut de Physique Nuclaire CNRS/IN2P3 Universit Paris Sud Orsay France

The electromagnetic probe is an excellent tool to investigate the structure of the nucleon. The nearly 4π detector PANDA, will allow to make a precise determination of the electromagnetic form factors of the proton in the time-like region with unprecedented precision. In the one-photon exchange approximation, the center of mass unpolarized differential cross section of the reaction pp → e＋e- is a linear combination of the squared moduli of the electric GE and magnetic GM proton form factors. The precise measurement of the angular distribution over almost full angular range then directly gives these quantities. At present only two experiments have provided the ratio R=｜ GE｜/｜GM｜ but with large statistical uncertainties. It is shown that with strict PID cuts and a kinematic fit, the dominant background, pp→π＋π-, can be supressed to much less than 1% of the signal, without affecting the extraction of the ratio R. PANDA will therefore offer a unique opportunity to measure the ratio with a precision ranging from 〈1% at low q2 up to 30 % for q2 = 14 （GeV/c）2.

关键词： electromagnetic form factors nuclear structure FAIR PANDA

A proposed U.S./China theoretical/experimental collaborative effort on baryon resonance extraction

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Chinese Physics C 2009年第12期33卷 1222-1229页

作者： Philip L. Cole Idaho State University Department of Physics Pocatello Idaho 83209-8106 USA

In this paper we discuss the reasons for our work towards establishing a new collaboration between Jefferson Lab （JLab） and the Institute of High Energy Physics （IHEP） in Beijing. We seek to combine experimentalists and theorists into a dedicated group focused on better understanding the current and future data from JLab and from the Beijing Electron Positron Collider （BEPC）. Recent JLab results on the extraction of single- and double-polarization observables in both the lπ- and 2π-channel show their high sensitivity to small production amplitudes and therefore their importance for the extraction of resonance parameters. The Beijing Electron Spectrometer （BES） at the BEPC has collected high statistics data on J/ψ production. Its decay into baryon-antibaryon channels offers a unique and complementary way of probing nucleon resonances. The CEBAF Large Acceptance Spectrometer, CLAS, has access to N＊ form factors at high Q2 which is advantageous for the study of dynamical properties of nucleon resonances, while the low-background BES results will be able to provide guidance for the search for less-dominant excited states at JLab. Moreover, with the recently approved experimental proposal Nucleon Resonance Studies with CLAS12 and the high-quality data streaming from BES-Ⅲand CLAS, the time has come for forging a new Trans-Pacific collaboration of theorists and experimentalists on NSTAR physics.

关键词： baryon resonances electromagnetic form factors J/ψ production CEBAF Large AcceptanceSpectrometer (CLAS) Jefferson Laboratory (JLab) Beijing Electron Spectrometer (BES) Beijing ElectronPositron Collider (BEPC) Institute of High Energy Physics (IHEP)