1992 Vol. 16, No. S3

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Measurement of Complete Fusion Excitation Function of 16O + 28Si Reaction
Zheng Jiwen, Zheng Pingzi, Liu Guoxing, Chen Keliang, Wang Sufang, Bai Xingping, Yu Xian, Zhang Huanqiao, Xu Jincheng, Liu Zuhua, Ruan Ming, Lu Jun, Xu Kan
1992, 16(S3): 227-234.
The complete fusion excitation function of the 16O + 28Si reaction is measured in the 50-90 MeV range with 1.0 MeV in step. By using some theoretical models,the result is analyzed and model parameters extracted. The gross structure is found in the excitation function when ECM < 46 MeV. The energies of peaks are 34.5,38.5 and 43.0 MeV, respectively. The structure vanishes gradually when ECM > 46.0 MeV.
Light Source for Synchrotron Radiation Topographical Study at Beijing Synchrotron Radiation Facility (BSRF)
Zhao Jivong, Yang Ping, Jiang Jianhua, Tian Yulian, Han Yong, Wang Chunxi, Shi Caitu, Xian Dingchang
1992, 16(S3): 235-241.
The characteristics of the synchrotron radiation (SR) source for X-ray topographical study at Beijing Synchrotron Radiation Facility (BSRF) are discussed, the spatial resolution of topographical study and the diffraction intensity from Li2B4O7 single crystal are given.
Hamiltonian Formula of WZNW Theory Under Chevalley Bases
Yang Huanxiong
1992, 16(S3): 243-252.
The Hamiltonian canonical formula of two-dimensional WZNW field theory based on arbitrary semi-simple Lie algebras is given under Chevalley bases. The Poisson brackets of conserved chiral currents are calculated, which are the classical Kac-Moody current algebras.
Angular Distributions and Generalized Moment Analysis for the Doubly Radiative Decay J/ψ → γγV
Shen Qixing, Yu Hong
1992, 16(S3): 253-265.
The doubly radiative decay process J/ψ → γX, X→γV, V→2P (or 3P) is discussed in this paper. For the intermediate state X with various spin-parity JP, the corresponding helicity formula of angular distribution formulas and the moments developed from the generalized moment analysis are presented. They are useful for determining the spin of the intermediate state.
Moment Analysis of the Wide Resonance θ(1720) in J/ψ Radiative Decay
Yu Hong, Shen Qixing, Zhu Yucan, Zheng Zhipeng, Cheng Zhengdong
1992, 16(S3): 267-276.
In this paper, the structure of the wide resonance θ (1720) produced in J/ψ radiative decays is studied by using the moment analysis. Since the f2'(1525) and θ (1720) resonances overlap in this mass region, two three-state coupling structure modes 2++ (f2'(1525)) + 0++ + 0++ and 2++(f2'(1525)) + 0++ + 2++ are discussed. This is helpful to make clear the structure of the wide resonance θ (1720),determine their masses,widths, spins and other important properties of the two resonance states, G(1590) and f2(1720).
A Study on the Polarization Structure of J/ψ →ωf2(1270) Decay Process
Yu Hong, Shen Qixing
1992, 16(S3): 277-280.
In this paper we investigate the polarization structure of the process J/ψωf2(1270) and f2(1270) → ππ by using the generalized moment analysis method and provide four helicity amplitude ratios of the process by using some moments relations.
The Influence of Nuclear Target on “Small” Mass Lepton Pair Production of High Energy Hadron-Nuclei Collision
Gao Yonghua, He Zhenmin, Huang Ruiwang, Peng Hong'an
1992, 16(S3): 281-289.
Based on Drell-Yan Mechanism modified by perturbative QCD and the contribution vector meson states,we analyze and explain the data of the WA-78 Group (π-,P) + A →μμ + X process at 2mμmμμ ≤ 1.5GeV and 0.1 ≤ xF ≤ 0.6, in which we use the rescaling model and the data of the NMC Group for the ratio of structure functions RA(x, Q2) in 1-A deep inelastic scattering process at 0.0035 < x < 0.65 and 0.5 < Q2 < 90 GeV2/c2. After a comparisdrwith the data of the CIP group for the same process but different xF and mμμ intervals, we explain why the influence of nuclear target displays a strong shadowing effect in the former case but a strong anti-shadovving effect in the latter. Using the rescaling model and other reasonable assumptions,we show that the above results are closely related to RA(x, Q2) and thus reveal the essential connection between the nuclear effects in 1-A deep inelastic scattering and in h-A pair production processes.
Multi-particle Azimuthal Correlations and the Nuclear Equation of State
Liu Qingjun, Jiang Yuzhen, Wang Shan, Liu Yiming, D. Keane, S. Y. Chu, S. Y. Fung
1992, 16(S3): 291-296.
Based on the method of Beckmann et al.,a new quantitative method is proposed for the study of multi-particle azimuthal correlations in relativistic heavy ion collisions. Multiparticle azimuthal correlations of nucleons for collisions of 12 A GeV Ar + KCl in the Bevalac streamer chamber are analyzed by this new method and Beckmann's. The experimental results are compared with the VUU model predictions for different nuclear equations of state. The incompressibility of nuclear matter can be estimated by the new method.
Spatial Parameter from Two-pion Interferometry
Huo Lei, Jiang Yuzhen, Wang Shan, Zhang Weining, Liu Yiming, D. Keane, S. Y. Chu, S. Y. Fung
1992, 16(S3): 297-303.
Comparing directly the correlation functions from different source density distributions, we propose that the average radius of the source obtained from two-pion interferometry analysis is quantity to describe the spatial size of the source. In the comparison the source spatial parameters from different correlation functions, the average radius of the source is a superior standard parameter to the root-mean-square radius suggested by Bartke and Kowalski, and is superior to the factor suggested by Goldhaber et al. A systematic study of the results from different heavy ion experiments demonstrates that a more reasonable result can be obtained by utilizing the average radius as a standard for comparison.
The Shape and Potential of Hot Nuclei in Symmetric Ternary Fission
Dai Guangxi
1992, 16(S3): 305-311.
The symmetric ternary fission (STF) in the shape of a spherical residue plus a three-rose-leaf-like rotating body (SRRL) is proposed to describe the large deformation from a sphere to the scission point with one deformation parameter. Based on the liquid drop model (LDM), the relative Coulomb and surface potentials with a sharp surface are calculated. Consequently, STF collective potentials in several nuclei are presented, and the shape and barrier height at the saddle point and the total kinetic energy (TKE) determined by Coulomb energy in the scission point are given. The shift of the center of mass (C.M.) for each pre-fragment in the STF process and deformation energies for new born fragments are also obtained. By considering the nuclear temperature dependence of the nuclear surface tension, the STF barrier height of the hot nucleus is decreased and then the transmission probabilities of STF are increased. The calculated results in the SRRL mode are compared with the previous results from the oblate shape model.
Mass Splitting of L=1 States of Quarkonium and Lorentz Structure of Long-range Confinement Potential
Luo Zhenfei, Qiu Xijun
1992, 16(S3): 313-320.
The Lorentz nature of the linear confinement potential between the quark-antiquark pair is analyzed by using the fine mass splitting data of L=1 spin triplets of the quarkonium. It is found that the linear confinement potential has a mixed nature of the Lorentz scalar and vector (0 ≤ η ≤ 29%, and η=0 represents the pure Lorentz scalar nature). By analyzing tentatively measured χ(11P1) and γ(11P1) masses,it is shown that in the linear confinement potential,a pure Lorentz scaler nature is required for the former meson, while the mixture of 79% Lorentz scalar and 21% Lorentz vector is required for the latter.
Nuclear Excitation by Electron Transition and γ-Ray Laser
Huo Yukun, Zhang Baohui, Yuan Zhushu
1992, 16(S3): 321-328.
Electron transition may induce nuclear excitation through virtual photon exchange (NEET). This paper discusses the possibility of transferring energies/from irradiation fields to nuclei by the NEET via atoms, the intermediate medium. A fonnula to calculate the NEET probabilities is presented, and the emphasis is put on the discussion of the transition matrix elements and selection rules. The predicted NEET probabilities for several nuclei are given and compared with the data. The upper limits of the NEET probabilities are estimated to be about lO-5. The conditions and possibilities to apply NEET to the γ-ray laser are discussed.
An Effective Hamiltonian in the Continuous Variable Representation of IBM-II
Di Yaomin, Ha Yiming, Fu Deji
1992, 16(S3): 329-337.
The dynamical aspects of IBM-II in the continuous variable representation are investigated by using the Dynamic Group Representation Generator Coordinate Method. The transformation from the degrees of freedom of proton and neutron to those of on-phase and out-of-phase motion is introduced and an effective Hamiltonian with this mode is derived. The features of the Hamiltonian, especially the minimum point of the system, are discussed.
Nuclear Macro-Microscopic Model
Hu Jimin, An Yu
1992, 16(S3): 339-342.
The extended Thomas-Fermi Approximation (ETF) is appUed to the study of the microscopic foundation of the continuous medium model of the nucleus, and a macroscopic model based on nucleon-nucleon interaction is obtained. With Skyrme force, it has been shown that the model reproduces the results of ETF calculations quite well.