1992 Vol. 16, No. S2

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Mössbauer Study of High Tc GdBa2Cu3O7-δ
Chen Zhiqian, Zheng Renrong, Yin Chuanzong
1992, 16(S2): 117-122.
57Fe-Mössbauer spectra of GdBa2(Cu1-xFex)3O7-δ(x=0.005) are studied in a wide temperature range (1.4-700 K), and the valence states and surroundings of iron cations are analyzed. There are four sites for Fe:A,B, C and D. Fe(A), Fe(B) and Fe(C) occupy Cu(l) sites with different O-coordinations. Fe(D) is attributed to a Cu(2) site with only one definite O-surrounding. The Fe cations are identified as high spin 4+ at site B and 3+ at site D. Alignment of polycrystalline powder absorber in a magnetic field leads to small texture effects.
Variation of the Intensity of High Energy Cosmic Ray Hadrons with Altitude
Lu Suiling, Ren Jingru, Su Shi, Wang Chengrui, He Mao
1992, 16(S2): 123-125.
By using small Pb emulsion chambers placed at a camping site for a Qomolangma (Everest) mountaineering team with an altitude of 6500 m a.s.l.,the intensity of high energy cosmic ray hadrons was determined. By combining the data with those observed at Mt. Kanbala (5500 m a.s.l.) and the Yunnan Cosmic Ray Observatory (3200 m a.s.l.), the altitude variation of high energy cosmic ray hadrons was obtained.
Two-Particle Pseudorapidity Correlations in pp Collisions at 400 GeV/c
Wang Shaoshun, Zhang Jie, Xiao Chenguo, Ye Yunxiu, Cheng Zhengdong, Zhang Xueqian, Luo Qi, Xu Wanli, Xiong Weijun
1992, 16(S2): 127-134.
The pseudorapidity distribution of charged particles produced in pp collisions at 400 GeV/c was measured by using LEBC films. The two-particle pseudorapidity correlations at fixed multiplicity were studied. The experimental data were fitted with cluster model. It was found that the average cluster multiplicities as well as the cluster decay widths vary slightly with charged multiplicity.
Experimental Investigation of the Decay Rate of Orthopositronium
Zhang Tianbao, Yang Guangming, Guo Baonian, Wang Haidong
1992, 16(S2): 135-140.
A method for the measurement of the vacuum decay rate λ0 of orthopositronium is presented and the preliminary result is λ0=7.034 ±0.013 μs-1. The possibility of improving the experiment is discussed.
Integrability of Liouville System on High Genus Riemannian Surface I. Classical Case
Chen YLxin, Gao Hongbo
1992, 16(S2): 141-153.
By using the theory of uniformization of Riemannian surface, we study the properties of the Liouville equation and its general solution on a Riemannian surface of genus g>1. After obtaining Hamiltonian formalism in terms of free fields and calculating classical exchange matrices, we prove the classical integrability of Liouville system on high genus Riemannian surface.
A Study on the Complete Integrability of the SU(2) and SU(3) Self-Dual Yang-Mills Source-Free Field Equation System
Li Fubin
1992, 16(S2): 155-161.
With the theory of harmonic maps and the eight-dimensional Riemannian manifold, the completely integrable SU(2) and SU(3) self-dual Yang-mills source-free field equations are described. Sixteen independent Killing vector fields are determined, two transformation groups which map solutions into solutions are constructed, and conjecture on the complete integrability of systems by the inverse scattering method is formulated.
The Crossing Matrices and Correlation Function of SUK(2) Wess-Zumino-Witten Model with Fractional Level
Hou Boyu, Shi Kangjie, Yue Ruihong
1992, 16(S2): 163-172.
By using the Feigin-Fuch integral, we calculate the correlation function, operator product coefficient and crossing matrices of the nonunitary SU(2) Wess-Zumino-Witten model. We also give the modular matrix from the fusion matrix and discuss the relations between the nonunitary SU(2) WZW model and the unitary one.
Construction of Creation-Annihilation Operators for Hydrogen Atom and Related Potentials with the Concepts of Supersymmetric Quantum Mechanics
Li Fubin
1992, 16(S2): 173-177.
Using new creation-annihilation operators constructed in this work, we are able to determine the eigenvalues and eigenfunctions of the hydrogen by the algebraic method, which is analogous to the well-known method for the harmonic oscillator.
Correction to Goldstein Equation from the Gluon Condensate Diagram
Bian Jianguo, Huang Tao
1992, 16(S2): 179-186.
An exact Goldstein solution of the Bethe-Salpeter equation for a vanishing total four-momentum in the ladder approximation of the free gluon exchange and the gloun condensating correction is discussed in detail. We find that the gluon condensate correction makes a pair of quark-antiquark more likely to form a bound state.
On the Exchange Algebra of Periodic WZNW Model
Zhao Liu
1992, 16(S2): 187-192.
Using the free field representation, we calculate the r-matrix and the classical exchange algebra for WZNW model under the periodic boundary condition, and discuss the quantum counterparts of the exchange algebra as well as the performance of the r-matrix and the classical exchange algebra under Hamiltonian reductions.
The Equation of State and Phase Structure in A Model with Dynamical Spontaneous Symmetry Breaking at Finite Temperature and Density
Wang Enke, Li Jiarong
1992, 16(S2): 193-200.
Based on the Lurie model, a convenient scheme is constructed for calculating the equation of state approximately. The parametric equation of state is given in the Lurie model. The phase diagram of the model shows the existence of a critical point separating first order from second order chiral phase transition. A careful analysis of the isotherms of pressure versus net baryon number density suggests the existence of overheat and overcool metastable state and the coexistence of broken phase and normal phase.
Evolution of Heavy Ion Reaction Mechanism in the Energy Region from 10 to 100 Me/A
Zhu Quaniing, Ge Lingxiao, Li Zhuxia
1992, 16(S2): 201-210.
The dynamical process of the heavy ion collision in the energy region from 10 to 100 MeV/A is investigated by the quantum molecular dynamics model. According to the calculated mass distribution, the evolution of the mass and density distribution with respect to time is calculated. The reaction mechanism and its characteristics are predicted and compared with those obtained from the BUU model.
Research on High Spin States of 68Ge,65Ga and 67Ga
Zhu Shengjiang, J. H. Hamilton, A. V. Ramayya, L. Chaturvedi, J. Kormicki, X. W. Zhao, I. Y. Lee, N. R. Johnson, C. Backtach, F. K. McGowan, M. L. Halbert, J. D. Cole
1992, 16(S2): 211-217.
The high spin states of 68Ge,65Ga and 67Ga are studied in the in-beam gamma-ray spectroscopy experiment. The reaction 46Ti (25Mg, xpxn) with the beam energy of 68 MeV is used. In 68Ge, the multiplicity of band structures, crossing transitions among bands and a new band with possible big deformation are observed. The experimental results agree with the calculated result in the new microscopic model (EXCITED FED VAJVIPIR). In 65Ga and 67Ga, some band structures with strong collectivity are observed and the new level schemes are given.
Monte Carlo Investigation of the Fractal Structure of Multiparticle Production in High Energy Collisions
Yu Lianzhi, Liu Lianshou, Cai Xu
1992, 16(S2): 219-226.
Fluctuations of the produced particles in the final states of high energy collisions may be the breakthrough in the investigation of multiparticle dynamics. How to eliminate the statistical noise of the system is one of the most important problems. In this paper, the influence of the statistical noise on fractal structure is analyzed and a method for eliminating the statistical noise is proposed by using the Monte Carlo simulation based on a simple dynamical model.