1992 Vol. 16, No. S1

Display Method:          |     

e/π Separation Analysis from L3 Calorimeter Beam Test
Chen Guoming, Chen Hesheng, Jin Bingnian, Tang Xiaowei, Tong Guoliang, Wu Yigen, Zhong Chongchang
1992, 16(S1): 1-10.
The L3 calorimeter beam test data are analyzed. An e/π separation scheme including "key cut" and "△ cut" is suggested. It is shown that by using this scheme, in the energy range 4-20 GeV, e/π separation is better than 93.7%,
Z0 Line Shape Fit
Jin Bingnian, Xu Yadi
1992, 16(S1): 11-16.
We describe a fitting method of the Z0 line shape, discuss the radiative corrections for calculating the theoretical cross sections of e+e- → ff at Z0 resonance, and compare the results from different programs. The systematic errors are taken into account in our fitting. As an example, Z0 line shape is fitted to determine some Z0 parameters by using the τ+τ- (γ) channel data.
A Study on the Correlation Between Projectile-Like Fragments and a-Particles in 20Ne(14.7,19.2 MeV/u) + 58Ni Reactions
Hu Xiaoqing, Zhu Yongtai, Shen Wenqing, Li Songiin, Zhan Wenlong, Xi Hongfei, Zhu Xiang, Zhang Zhen
1992, 16(S1): 17-22.
The coincidence between projectile-like fragments and a-particles emitted from 20Ne (14.7 MeV/u,192 MeV/u) + 58Ni reactions has been studied. The coincident events were caused by the sequential decay of the excited primary fragments and by the "uncorrelated" coincidence between forward emitted α-particles and projectile-like fragments, which formed in a deeply dissipated reaction process. This reaction process means that the a-particle flied off the 20Ne projectile in the initial stage of the reaction and then the residual 16O collided with the target nucleus dissipatively. We call it "incomplete deep inelastic process".
Numerical Computation of Self-Sustaining Magnetically Confined Electron Clouds
Huang Jiachang
1992, 16(S1): 23-31.
In this paper, the axisymmetricai self-sustaining magnetically confined electron clouds are studied by means of the numerical computational method on the basis of the fluid theory./The electron density distribution, electric potential distribution, drift angular frequency and electron temperature can be calculated with a simplified method in which the nearequilibrium state approximation is necessary. The results are, in principle, in agreement with the experiments.
A New Search for 1-+ Exotic State
Yu Hong, Shen Qixing
1992, 16(S1): 33-39.
For the purpose of data analysis with BES (Beijing Spectrometer), some new relations, which can be used to search for the 1-+ exotic state in J/ψωX,X → KKx, are obtained. How to search for the 1-+ exotic state in the three-step two-body hadronic decay process J/ψωX,X → KK*, K*→Kx is also discussed.
Spin and Parity Analysis for the Three-Step Two-Body Hadronic Decay Processes of J/ψ
Qixing Shen, Hong Yu
1992, 16(S1): 41-50.
This paper presents the helicity formalism of the angular distribution for the cascade decay processes e+ + e- → J/ψ → V + X,X → P1 + Y,Y → P2 + P3 (V represents a vector meson and Pi(i=1,2,3) are the pseudoscalar mesons). It provides the theoretical formulas for the spin-parity analysis of the intermediate state X through a three-step two-body hadronic decay processes of J/ψ.
Effective Topological Action in Heisenberg Spin Model as Berry's Phase
Sun Changpu, Pang Lin, Ge Molin
1992, 16(S1): 51-56.
This paper shows that the topologically additional action appearing in the Heisenberg spin model can be understood as superposition of Berry's phase for the single spins in an average fields of many particles. In the case of low temperature, using the high order adiabatic approximation method,we obtain higher order corrections for this action.
A Conjecture for the Applicability Condition of Jimbo's Method
Ma Zhongqi
1992, 16(S1): 57-64.
According to Jimbo's theorem, the method for constructing the spectrum-dependent solutions to the Yang-Baxter equation is based on the existence of the representation matrix of e0 that corresponds to the lowest negative root, in an irreducible representation of a quantum enveloping algebra. This paper discusses a conjecture for the existence condition of the representation matrix of e0. As an example, the adjoin representation of UqC2 is discussed where the representation matrix e0 does not exist because the existence condition is violated.
The Origin and Universality of “Spin Suppression” in Baryon Production
Xie Qubing
1992, 16(S1): 65-71.
In high energy reactions the production of spin (3/2)+ baryons is strongly suppressed in comparison with that of (1/2)+ baryons. I show that the observed λ broken SUf(3) symmetry in multihadron production is consistent with stochastic quark arrangement, and this self-consistency determines the ratios among SUf(3) singlet, octet and decuplet, including all of their excited states. But for (1/2)+ and (3/2)+ baryon production, as in the case of the popular models, then the strangeness suppression factor λ=<NS>/<Nu> completely determines the ratio of (3/2)+ to (1/2)+, and β=(1 + λ)/(3 + 2λ). The universality of this relation is emphasized.
A Study of the Relativistic Microscopic Optical Potential Based on the Relativistic Brueckner-Bethe-Goldstone Equation
Chen Baoqiu, Ma Zhongyu
1992, 16(S1): 73-81.
A relativistic microscopic nucleon-nucleus optical potential is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation. The complex effective mass of a nucleon is determined by a fit to the scattering data for P-40Ca at 200 MeV, The relativistic microscopic optical potentials with this effective mass are obtained from the RBBG equation for P-16O, 40Ca, 40Zr, 208Pb scatterings in the energy range from 160 to 800 MeV. The microscopic optical potential is used to study the P-40Ca scattering problem at 200 MeV. The results, such as differential cross section, analyzing power and spin rotation function, are compared with those calculated from the phenomenological relativistic potentials.
Two Normalization Schemes of Factorial Moments in High Energy Collisions and the Dependence of Intermittency Indices on Average Transverse Momentum
Wu Yuanfang, Liu Lianshou
1992, 16(S1): 83-89.
Two different types of normalization of factorial moment are analyzed in detail. It is found that in the case of fixed multiplicity and of intermittency degree independent of multiplicity, the intermittency indices obtained from these two kinds of normalization are equal. In the case of unfixed multiplicity and of intermittency degree depending on multiplicity, the intermittency indices obtained from these two different types of normalization are expressed in terms of the dynamical ones. The experimentally observed dependence of intermittency on transverse momentum cuts are also discussed under the assumption that the intermittency degree depends on the average transverse momentum of each event. It confirms the importance of average transverse momentum in determining the intermittency degree.
Color Screening Effect and Baryon Spectra
Yang Hua, Deng Weizhen, Zhang Zongye
1992, 16(S1): 91-100.
By using the color confinement potential which includes the color screening effect obtained from the lattice gauge calculation, we studied the structure of the baryons, and calculated the baryon spectra and the square root radii of the corresponding states.
Intranuclear Cascade and Target Fragmentation in High Energy hA Collisions
Wang Haiqiao, Cai Xu, Liu Yong
1992, 16(S1): 101-106.
A model for describing the target fragmentation in high energy hadron-nucleus collisions based on the intranuclear cascade is suggested. An analysis of the correlation between grey and black particles shows that the saturation of the mean number of grey and/or black particles observed in experiments result from the limitation of the charge number in the nucleus.
Particle-Hole State Densitiy with Energy Constraints and Exact Pauli Exclusion Effect
Mao Mingde, Guo Hua
1992, 16(S1): 107-116.
A formula is derived for the density of particle-hoie states in the equidistant spacing model. The formula gives full consideration to the effect of the Pauli exclusion principle. The pairing effect and two energy constrains are considered. The formula is easy to use and can be easily extended to the case where protons and neutrons are distinguished. The calculations indicate that the Pauli effect and the pairing effect play an important role in particle-hole state density.