1993 Vol. 17, No. S2

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A Method for Identifying Medium-Heavy Products of Heavy Ion Reaction at SPEG Spectrometer
Feng Jun, Shen Wenqing, Ma Yugang, Zhan Wenlong, Zhu Yongtai, Guo Zhongyan
1993, 17(S2): 95-100.
A method for identifying medium-heavy products of heavy ion reaction on magnetic spectrometer with a set of focal plane detector is developed. The atomic number, the charge state, the atomic mass of fragments in the reaction of 44 MeV/u 129Xe beam on 90Zr and 197Au targets are obtained by this method. This is the first time such heavy reaction products on the magnetic spectrometer at intermediate energy have been identified.
Microstructure of Al/GaAs Interface Studied by Slow Positron Beam
Weng Huimin, Zhou Xianyi, Xu Jihua, Sun Shijun, Zhu Jingsheng, Wu Shulan, Han Rongdian
1993, 17(S2): 101-109.
The interface models were founded, and the expressions of the relation between Doppler broadening S-parameter and the implanted energy of positrons were got based on the diffusion equation of positrons. Interfaces formed between AI overlayer and the (110) surface of GaAs were studied with slow positron beam. We found the system of AI/GaAs interfaces could be well described by the perfectly absorbing linear interface model. From the results fitted by this model, we obtained the relation between the 5-parameter of the interface and the annealing temperatures or the overlayer thickness. The microstructure of interfaces and its dynamical characters were discussed.
A New Symmetric Transformation of the Static Axially Symmetric SDYM Fields
Hao Sanru
1993, 17(S2): 111-116.
By means of the solutions to the Lax pair of the static axially symmetric self-dual Yang-Mills (SDYM) fields, the new symmetric transformation of the static axially symmetric SDYM fields is constructed.
Determination of the Spin-parity of the Particle X for the Process J/ψ V1+X, X→V2+V3 by Using the Generalized Moment Analysis
Shen Qixing, Yu Hong
1993, 17(S2): 117-124.
The hadronic decay process of J/ψ, J/ψ→V1+ X, X→V2 + V3, V2, V3→2P or 3P (where Vi and P represent the massive vector and pseudoscalar mesons, respectively), is discussed by using the generalized moment analysis in this paper. The corresponding moment formulae for the intermediate state X with various spin-parity are presented. The values of helicity amplitudes for the X→V2 + V3 process are calculated in the nonrelativistic case. The spin, parity and partial wave state of the intermediate particle X can be determined by comparing the theoretical moments with the data.
The Implications of the New Measurement of Lepton τ Mass
Wu Jimin, He Zhuoxiu
1993, 17(S2): 125-131.
The physical implications for the new measurement of lepton τ mass is discussed. The lifetime of τ is predicted.
The Solution of Dynamical Equation of Motion of IBM-II in Continuous Variable Representation
Di Yaomin, Ha Yiming, Fu Deji, Xu Gongou
1993, 17(S2): 133-142.
In this article the solution of the dynamical equation of motion in the continuous variable representation is discussed. With appropriate transformation and approximation, the nophase part of system manifests the vibration-rotation mode and the out-of-part shows the "scissor mode" etc. The energy spectrum of 156Gd is also calculated, and the algebraic results of IBM-II can be well reproduced.
Studies of the θ(1720) Wide Resonance in J/ψ Hadronic Decays
Yu Hong, Shen Qixing, Zhu Yucan, Zheng Zhipeng, Cheng Zhengdong
1993, 17(S2): 143-146.
In this paper the structure of the θ(1720) wide resonance produced in J/ψ hadronic decays is studied by using the generalized moment analysis. Since the production yield of the f2'(1525) is very small, we may neglect the influence of the f2'(1525) is larger we must consider the coherence effects of the f2'(1525) for the process J/ψωθ(1720). Whereas the production yield of the f2'(1525) is larger we must consider the coherence effects of the f2'(1525) for the process J/ψωθ(1720). From the studies of the above two processes and the corresponding J/ψ radiative decay process we are able to understand the structure of the θ(1720) wide resonance better.
The Structures of Color String for e+e-→qqg and Y→3g
Tian Lili, Xie Qubing, Si Zongguo
1993, 17(S2): 147-156.
In the LUND model, the explanations of e+e-→qqg→3jets and Y→3g→h's are based on the application of the LUND string fragmentation model to the color string structures of qqg and 3g systems. In this paper, starting from the color wave functions of the qqg and 3g systems, these color string structure are directly studied by using QCD. It is shown that the reasonableness and accuracy of the LUND string picture are revealed.
Valence Quark Mixing Contribution to the Gottfried Sum Rule
Zhu Wei
1993, 17(S2): 157-159.
This paper discusses the mixing effect of valence quark in deep inelastic processes. This effect, together with the contribution of the meson cloud, dominates the break of the Gottfried sum rule.
An Accurate Calculation of the Superdeformed Bands in Hg and Pb
Lei Yian, Zeng Jinyan
1993, 17(S2): 161-169.
The superdeformed (SD) rotational bands in the Hg and Pb isotopes are analyzed by means of the abc expression for rotational band:Eγ(I)=a[1 + cI(I+l)] [√1 + bI(I + 1) -1], which was derived from the Bohr Hamiltonian. The agreement between the calculated and observed transition energies is remarkably good. The deviation of the calculated E s from the observed ones turns out to be|δ|≤ 0.5 keV (except for a few cases, 0.5 keV ≤ |δ| ≤ 0.7 keV). Some transitions which have not been observed yet in these SD bands are predicted, which may be useful for experimental investigations.
Study of Antihydrogen-Atom Formation in Antiproton-Positronium Collisions
Cheng Zitao, Qian Qing, Fu Yunchang, Chen Xuejun
1993, 17(S2): 171-178.
Some properties of antihydrogen-atom formations in antiproton-positronium collisions have been studied theoretically. The possibility of producing antihydrogen atoms in the laboratory is also discussed.
Effect of Interaction Range in Relativistic Microscopic Optical Potential
Zhu Ping, Xu Jiabao, Gao Qin
1993, 17(S2): 179-189.
In the Walecka model of the relativistic nucleon-meson field theory, by using the models nucleon-nucleon interaction, the optical potential (OP) in the local density approximation (LDA) is folded, so that the effect of the interaction range on the relativistic nucleon-nucleus microscopic optical potential can be discussed. With this OP, the differential cross section of the nuclear elastic scattering and spin observables are analyzed. Comparing with the result calculated in LDA, a better agreement between our result and the experimental data is obtained.
Effects of Different Kinds of Confinement Potentials and Configuration Space on N and Δ Spectra
Dong Yubing, Yu Youwen
1993, 17(S2): 191-198.
In this paper, the confinement potential with color screening effect, higher level configuration mixing, basis wave functions with different size parameters, and vectorcoupling component are employed to study the spectra of the N and Δ systems. The result shows that these facts can improve theoretical results and give better descriptions for the N and Δ spectra.
Antiproton-Nucleus Elastic Scatting at Intermediate Energies
Li Yangguo
1993, 17(S2): 199-205.
Using the experimental pN amplitudes and the multiple scattering theory, we obtained the antiproton potential at incident energies from 180 to 1800 MeV under the impulse approximation. We found that the imaginary parts of the optical potential strengths are nearly constant from 130 to 140 MeV. By using these optical potentials, we obtain the calculation results of the elastic scattering differential cross sections from the closed shell nuclei 12C, 16O, 40Ca and 208Pb for five kinetic energies ranging from 180 to 1800 MeV. At 180 MeV, the experimental data are fitted very well, and the theoretical results at higher energies are predicted.
Color Screening Effect and Nucleon-Nucleon Interaction
Shen Xiaoyan, Shen Pengnian, Yu Youwen, Zhang Zongye
1993, 17(S2): 207-213.
The nucleon-nucleon interaction is studied in terms of a color confinement potential where the color screening effect is involved. It is shown that by using this confinement potential but not the linear or quadratic potential, the color Van der Waals force no longer has irrational long tail, while it provides a part of the medium-range attraction of the nucleon-nucleon force.