1991 Vol. 15, No. S2

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Construction and Inspection of End-Cap Shower Counters for Beijing Spectrometer
Li Jin, Wang Man, Cui Xiangzong, Wang Linzhou, Xia Xiaomi, Lai Yuanfen, Li Lili, Wang Zhongji, Zheng Jianping, Yao Xiaoguang, Lu Weida
1991, 15(S2): 101-107.
In this paper, the structure and technology of the End-Cap Shower Counters for Beijing Spectrometer are described. The tension of anode wires, leakage currents and some inspection results of sampling tubes are given.
Observation of Superhigh Energy Muons with Large Zenith Angles in Mountain Emulsion Chambers
Fan Xiaoling, Su Shi, Wang Yi
1991, 15(S2): 109-117.
After 215 blocks of K6, K7 and K8 lead emulsion chambers of the Mt. Kanbala experiment are carefully scanned, 111 muon events with zenith angle M (=tgθ) ≥ 2.5 are found. The energy of muon showers are determined by saddle-shape curves. The intensity of muons, the shower energy spectrum and the zenith angle distribution of muon showers on the altitude of 5500 m above sea level are obtained in the energy region Eμ ≥ 2 TeV. Meanwhile, the simulation calculation is made in order to study the behavior of muons inside the emulsion chamber. The results of the simulation are basically in agreement with the experiment.
Calculation of Space Charge Field for Annulus and Disc Bunch of Charged Particles
Song Zhongheng, Wang Xiaomin
1991, 15(S2): 119-125.
The formulas of the space charge field for annulus and variable disc bunch of charged particles and the methods of the calculation are developed. The usage of the calculation results in the field of computer simulation of the beam dynamics is introduced.
The Magnetically Confined Electron Cloud Sustained by Thermionic Emission
Yu Qingchang
1991, 15(S2): 127-131.
The electron clouds in high vacuum confined by electromagnetic fields and sustained by thermionic emission are studied. The density distribution, temperature, drift angular velocity and diffusion flow density of the electrons and the electric potential in the clouds are discussed.
The Experimental Terminal with Large-Area Ionization Chambers at Lanzhou Heavy-Ion Accelerator
Feng Enpu, Zhu Yongtai, Guo Zhongyan, Qiao Weimin, Zhan Wenlong, Shen Wenqing, Wang Xiaoqiu, Wang Bing, Yin Shuzhi, Feng Jun, Liu Guanhua, Xi Hongfei, Fan Enjie, Zhu Xiang, Zhou Jianqun, Zeng Yaowu
1991, 15(S2): 133-140.
This report describes the experimental terminal of the large-area ionization chamber connected with the HIRFL accelerator in Lanzhou. The basic structure of the terminal and detector systems is introduced. Some measurement results of the detectors are given. Certain research subjects on reaction mechanism at intermediate energy with this terminal are also presented.
Bjorken-Johnson-Low Technique and a Perturbative Study on Chiral Anomaly in Pure Abelian Coset Gauge Field Theory
Jing Sicong, Ruan Jie
1991, 15(S2): 141-152.
The perturbative theory in the pure coset gauge field theory is studied in this paper. By using the Bjorken-Johnson-Low technique and calculating the Schwinger term in related commutators, the anomalous Ward identity in the pure Abelian coset gauge field theory is derived and found consistent with the non-perturbative calculation.
The Polarization States of the Gluon and the Glueball Interpretation of the ξ (2230)
Shen Qixing, Yu Hong
1991, 15(S2): 153-157.
The glueball interpretation of the ξ (2230) is discussed when the gluon has only the transverse polarization components.
Rapidity Distribution of Negatively Charged Particles in RHIC
Liu Bo, Zhao Weiqin
1991, 15(S2): 159-163.
Based on the two-fireball model, the multiparticle production process in p-p collisions is described. In terms of the geometrical model of nuclear collisions, the rapidity distribution of negatively charged particles obtained by NA35 group is fitted and a strong correlation between the impact parameter b and the multiplicity n_is found.
High Spin Level Structure in 153Dy and Shape Changes in Neutron-Deficient Dy Nuclei
Zhu Shengjiang, Ma Wenchao, Ahmad, B. Dichter, H. Emling, R. Holzman, R. V. F. Janssens, T. L. Khoo, M. Quader, P. J. Daly, Z. Grabowski, M. Piiparinen, W. Trzaska, M. W. Drigert, U. Garg
1991, 15(S2): 165-171.
High spin state in 153Dy is studied up to 81/2 h through the in-beam γ-ray spectroscopy technique. The reaction of 122Sn (36S, 5n) is used at a beam energy of 165 MeV. Above the I=47/2 h isomeric state, complex single-particle structure is dominant along the yrast line and in its close vicinity. Nuclear shape changes of neutron deficient Dy isotopes with neutron number N and spin I are discussed.
Relationships Between the Gap at Z=64 Subshell and the Abrupt Transition in the Region of N=88~90
Sang Jianping, Liu Chaoshan, Liu Yong
1991, 15(S2): 173-181.
The onset of deformation in the N=88~90 region and the effects of the gap at the Z=64 subshell on nuclear structure are investigated in a microscopic approach of the interacting boson model. Besides the n-p interaction, the distribution of single particle levels in the shell model space also is found to play a direct and important role in the rapid transition of the spectrum structure. For Nd~Dy nuclei,the calculations show excellent agreement with the experimental energy systematics.
A Microscopic IBM-2 Description of the Phase Transitions of Nuclear Spectrum Structure Near A=130
Li Xianyin, Zhao Xiaofeng
1991, 15(S2): 183-188.
The phase transitions of the low-lying energy spectrum structure of the Ba isotopes and Sm isotopes are studied in the framework of the microscopic IBM-2 based on the boson expansion. It seems possible to describe the phase transitions in a uniform way by this approach.
The Staggering Phenomenon in the Nuclear Energy Spectrum and the Quadruple Interaction
Liu Yuxin, Long Guilin, Sun Hongzhou
1991, 15(S2): 189-195.
An improved approach to the treatment of the staggering phenomenon in nuclear energy spectra in the framework of the IBM2 is described in this paper. By applying this approach to the even-even isotopes, Ru and Pt, the relation between the staggering phenomenon and the quadruple-quadruple interaction is discussed.
Parton Evolution Model and the EMC Effect
Yang Jianjun, Zhu Yabo, Shen Hongqing, Shen Jianping, Li Guanglie
1991, 15(S2): 197-205.
The effect of the evolution of partons in the nuclear environment on the structure function of nucleons bound in a nucleus is investigated. Together with the nuclear shadowing effect caused by the spatial overlap of partons from neighboring nucleons in the nucleus in the small x region, the ratio of the average nuclear structure function of nucleus 56Fe to the deuteron structure function is calculated and a good agreement between the calculated results and the experimental data is obtained.
The Restoration of Symmetry and Plasmon Effects at High Temperature and Density in the Weinberg-Salam Model
Hou Defu, Li Jiarong
1991, 15(S2): 207-217.
The effective potential of the W-S model is calculated both at finite temperature and density from the entire Lagrangian according to the grand canonical ensemble temperature field theory. The two elementary thermal effects in the weak and electromagnetic system are studied. The result indicates that the thermal effects not only counteract the Higgs mechanism effect and help restore the symmetry, but also make the gauge particles keep nonvanishing mass due to the plasmon effects.