1990 Vol. 14, No. S4

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The Design and Construction of the BES Main Drift Chamber
Ma Jimao, Mao Huishun, Bai Jingzhi, Xie Peipei, Yan Jie, Wang Yaohui, Mao Zepu, Liu Rongguang, Shen Benwei, Song Xiaofei, Zhou Jie, Wu Zhendong, Fan Qun, Jin Yan, Rong Gang
1990, 14(S4): 325-337.
The main drift chamber of the Beijing Spectrometer (BES) is briefly described, including its physical design, mechanical design and construction, choice of the working gas as well as the prototype test. The performance of the chamber, experimental and expected value are given, such as solid angle coverage, gain and efficiency, spatial resolution in the R-ϕ plane, axial spatial resolution, dE/dx energy resolution, particle identification, etc.
Thermionic Cathode Microwave Electron Gun
Xie Jialin, Gao Jie, Huang Yonzhang, Zhang Renshan, Wang Youzhi
1990, 14(S4): 339-348.
The principle and development of the thermionic cathode electron gun used as a injector of a high brightness RF linac are introduced. The numerical computation of the beam current, energy spread and emittance are given. A prototype of the gun was tested and some experiment results are reported. The paper concludes with a discussion of the existing problems and possible improvements in its performance.
(φφ) in the Tree Graph Approximation
Li Zhibing
1990, 14(S4): 349-351.
The condensation of the naive Fermions in an arbitrary dimensional lattice is given in the tree graph approximation. No chiral symmetry spontaneous breaking is found.
A Moment Analysis for the J/ψ Hadronic Decay Processes
Yu Hong, Shen Qixing
1990, 14(S4): 353-360.
In this paper the helicity formalism of the angular distributions for processes e+e-→J/ψ→V + X, V→P1P2 or V→P1P2P3 and X→PP are given simultaneously. On the basis of the formalism a moment analysis is made and some relations are obtained which can be used for determining the spin Jx of the boson resonance X and the helicity amplitude ratios of the process/ψ→V + X.
Azimuthal Correlation Function and the Nuclear Equation of State
Wang Shan, Liu Yiming, Jiang Yuzhen, Chen Xiaofan, D. Keane, S. Y. Fung, S. Y. Chu
1990, 14(S4): 361-366.
Collisions of 1.2 A GeV Ar on KCI in the Bevalac Streamer Chamber are studied using two methods:azimuthal distribution analysis and azimuthal correlation function analysis. Comparing with VUU (Vlasov-Uehling-Uhlenbeck) model predictions for different nuclear equations of state, the stiffness of the high density nuclear matter is estimated. The maximum azimuthal anisotropy inferred from the azimuthal distribution method is decreased by about 30% because of dispersion of the azimuthal angle of the reaction plane. This distortion can be eliminated by using the azimuthal correlation function analysis proposed in this paper.
Analytical Treatment of SU(2)-Higgs System on Lattice at Finite Temperature
Zheng Xite, Liu Beishu
1990, 14(S4): 367-375.
The variational cumulant expansion treatment of lattice gauge theory at finite temperature is developed to the lattice SU/(2)-Higgs system with the Higgs fields in the fundamental representation. The method is demonstrated by calculating the expectation value of Polyakov line <L> to the 3rd order approximation. The result is in agreement with the Monte Carlo simulation result. The comparison with the mean field results is given.
Equivalent Meson Exchange Potential on Quark Model and N-N Scattering
Yu Youwen, Shen Pengnian, Zhang Zongye
1990, 14(S4): 377-380.
The S wave phase shifts of the N-N scattering are calculated by using the equivalent one meson exchange potential (EOMEP) and the equivalent 2x exchange potential (ETPEP) from the quark-antiquark pair creation model. The result shows that EOMEP and ETPEP can provide a portion of the medium attractive nature of the nuclear force.
A Chiral Quark-Soliton Model Theory for Nuclear Force
Xu Xiaoming, Qiu Xijun
1990, 14(S4): 381-389.
The chiral quark-soliton model with one gluon exchange is briefly described. The quark-gluon coupling constant and quark wave functions determined in the soliton model are used as input for the relativistic two-quark-cluster theory. In this paper the two-nucleon system is studied. Two terms of the kinetic energy and relative-motion energy in the quark-exchange kernel are taken into account. Therefore, the phase shifts for 3S1 and 1S0 channels are improved. The phase shifts are in agreement with Arndt's. It is shown by our calculations that one-gluon-exchange and quark-exchange provide a short-range repulsive potential and the chiral field produces the middle- and long-rang attractive potential.
Experiments with Joined in-beam γ Equipment
Guo Yingxiang, Sun Xiangfu, Luo Ybdao, Lei Xiangguo, Sun Xijun, Xu Xiaoji, Zhao Zhizheng, Wang Jicheng, Yu Jianfang, Wen Shuxian, Li Shenggang, Weng Peikun, Hua Pengfei, Li Guangsheng, Yuan Guanjun, Zhu Lihua, Zhang Lankuan, Yu Panshui, Yan Chunxiang
1990, 14(S4): 391-397.
Four symmetric and 6 asymmetric BGO Compton shielded HpGe detectors which constitute the Joined In-Beam Gamma Equipment have been completed and tested at the Institute of Atomic Energy (Beijing) and Institute of Modern Physics (Lanzhou) respectively. The first set of experiments has been carried out by using the equipment. This paper describes the experimental set up and general cases of the measurements. A discussion about Compton suppression is given. The observed 25/2+ of the ΔJ=1 band built on the 9/2+ (lg9/2 proton hole) state of 121Cs is the highest spin level among the similar bands of Cs isotopes.
Fission Measurement on 5.5 to 22 MeV/A 28Si + 197Au Systems (I) Linear Momentum Transfer and Angular Distribution off Reaction Plane
Dai Guangxi, Qi Yujin, Zheng Jiwen, Liu Ximing, Chen Yuanda, R. Stokstad, J. Pouliot, A. Harmon, D. Digregorio
1990, 14(S4): 399-406.
The velocities and angular distributions of correlated fission fragments emitted from reaction of 197Au bombarded by a 28Si beam with energies from 5.5 to 21.7 MeV/A are measured. The results show that when the incident energy is larger than 10 MeV/A, the incomplete fusion-fission (ICF) associated with incomplete linear momentum transfer (LMT) appears. Furthermore, when Ecm > 200 MeV, as a companion of ICF, the sequential fission (SF) with lower LMT than that of ICF, has apparent yields. By comparing the difference of LMT values from ICF and SF, the ratio of SF over total fission cross-section has been obtained. Moreover, the angular distribution off the reaction plane of one fragment and its standard deviation have been obtained. It seems that there is a general linear relationship between the deviation and excitation energy per nucleon in heavier composite systems.
Contribution of the 2H-1P Multiple Scattering Correlation and Self Screening Effect to the Spectra of 17O and 15O
Li Yuncai, Yang Shande, Wu Shishu
1990, 14(S4): 407-415.
The contribution of the 2H-1P multiple scattering correlation and the PH TDA selfscreening to the low energy spectra of 17O and 15O is investigated in various approximations by the method of Green's function and the partial summation of multiple scattering. In our calculation, the nuclear force employed is the Paris potential and the energy dependence on G matrices has been rigorously taken into account.
Study on Target Residues from the Interaction of Copper with 44 MeV/A 12C Ions
Li Wenxin, Sun Tongyu, Sun Rulin, Wu Dingqing, Zhao Lili, Jing Genming, Qi Dahai, Sa Benhao
1990, 14(S4): 417-426.
Cross sections and average forward ranges were determined for 35 target residues from the interaction of copper with 44 MeV/A 12C ions by nuclear chemistry techniques. From these data the isobaric yield distribution, the mass yield distribution and the longitudinal momentum transfer were obtained. The mass yield distribution and the isobaric yield distribution are in good agreement with those calculated from a modified statistical model and corresponding Monte Carlo technique.
Analytical Expressions of Some Isoscalar Factors for UN⊃G
Pan Feng, Cao Yufang
1990, 14(S4): 427-430.
Analytical expressions of some isoscalar factors for U6SU3, UN⊃(U1)N and SO7⊃(SU2)3 are derived.