1994 Vol. 18, No. 5

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Simulation of The Fission Fragment Angular Correlation For 16O+232Th At Barrier Energies
Qian Xing, Xu Jincheng, Liu Zuhua, Zhang Huanqiao, Jiang Dongxing, Ye Yanlin
1994, 18(5): 385-391.
Fission fragment angular correlations and angular distributions have been simulated for 16O+232Th System at Sub-barrier energies. the combined kinematic effectsof the distributions in mass, energy and angular for the heavy fragments and prescission, post-scission neutron emission have been considered. The completed fusionfission and transfer-fission components can be separated by using fission fragmentangular correlation technique with the Monte-Carlo simulation. The influence of prescission neutron emission and transfer fission on fission fragment anisotropies hasbeen considered. The anamalous anisotropies still persist.
The Study of Particle Densities in Pseudorapidity Space in pp collisions at 400GeV/c
Wang Shaoshun, Xiao Chenguo, Zhang Jie, Xia Xiaojuan, Xiong Weijun, Zhong Yu
1994, 18(5): 392-397.
The pseudorapidity distributions for charged particle multiplicity 4-24 produced in pp collisions at 400 GeV/c have been measured by using the LEBC films which were offered by CERN NA27 Collaboration. The regularity that the average maximum charged particle density in a selected pseudorapidity window (Δη=0.5 or 0.1) is rising linearly with the charged particle multiplicity was observed. There is a trend that the probability distributions of the maximum Particle density at large n become wider and flatter. But the event that the maximum particle density. is anomalously high was not observed.
Excitation Functions of DIC Products in the Reaction of 19F+45Sc
Wang Qi, Li Songlin, Lu Jun, Xu Hushan, Yin Xu, Fan Enjie, Guo Zhongyan, Zhu Yongtai, Xie Yuanxiang, Li Zhichang, Lu Xiuqin, Hu Xiaoqing
1994, 18(5): 398-403.
Excitation functions have been measured for the dissipative reaction products at θl=26°and θl=42°in tEe 102 MeV to 108 MeV 19F8++45Sc reactions by a step of 300 keV. The energy coherence widths and the dinuclear system lifetimes are extracted by analysing the cross section fluctuations. The dissipative reaction mechanisms are investigated.
Search for Light Neutral Particle in Low Energy e+e Annihilation
He Jingtang, Zhu Guoyi, La Yusheng, Dong Xiaoli
1994, 18(5): 404-408.
This paper reports the experiment result from a search for light neutral particle U by measuring the monoenergetic gamma ray in the singlet positronium annihilation: e+e(1S0)→γ+U. No evidence for the existence of such a particle of mass Mu<2me has been found on the level of 2σ statndard deviation.
An SU(5) Grand Unified Model with Hadrons as Nontopological Solitons (Ⅱ)
Chen Shihao
1994, 18(5): 409-416.
The interactions of fermions with gauge fields in the SU(5) grand unified model presented in the preceding paper are discussed. The electroweak interactions obtained from the present model are consistent with the standard model, the gauge interactions inside a soliton are approximate to the known QCD. It is proven that only charge Q0 can be detected experimentally, and the interior charge Qi presented in the preceding paper cannot be detected. A possible explanation of the origin of fractional charge is presented. Only electroweak interactions of three generations of leptons are the same. Their interactions with unknown gauge fields are different. Before spontaneous symmetry breaking sinθw= 1/2.
Vacuum Wave Function Study of 2+1 Dimensional SU(2) Gauge Field
Chen Qizhou, Li Lei, Li Zhibing, Guo Shuohong
1994, 18(5): 417-423.
We study the vacuum wave function by three different methods: the strong coupling expansion method, the eigenfunction method, and the variational method. Comparison between the results is made.
Equation of State in the F-L Model and a Physical Picture of Deconfinement Transition
Deng Shenghua, Li Jiarong
1994, 18(5): 424-427.
The equation of state in the F-L model is calculated at finite temperature and density it turns out from the analysis of the isotherms of pressure versus net baryon number density that, in the mean-field approximation, the deconfinement phase transition in the F-L model is of first order.
Intermittency in the Heavy ion Collisions at Intermediate and High Energies
Ge Lingxiao, Zhang Xiaodong, Zhu Quanling
1994, 18(5): 428-432.
The method of scaled factorial moments is used to study fluctuations of the fragment-size distribution based on the quantum molecular dynamics model. From the calculation of 197An (200MeV/u) +197Au central collision system, an intermittent pattern of fluctuations is found. In particular, the critical behavior is preliminarily discussed.
Application of Self-Affine Fractality in High Energy Multiparticle Production
Wu Yuanfang, Liu Lianshou
1994, 18(5): 433-438.
A fractal object is self-affine instead of self-similar if it has different scaling property in different direction. It is pointed that the fractality in high energy multiparticle production belongs to this category. A method is proposed to examine the self-affinity experimentally and to measure the characteristic parameter of self-affinity, the Hurst exponent.
An Examination of the Cluster Structure for 16O by Means of Heavy-ion Scattering
Li Qingrun, Yang Yongxu
1994, 18(5): 439-442.
The cluster structure of 16O is examined by means of heavy-ion scattering. The comparison of the present results with those by other models is made. The results provide a support to the cluster structure of 16O.
Contribution Due to Gluon Shadowing and Final-State Interactions to Charmonium/Bottonium Suppression in h-A Collisions
Liu Bo, Zhao Weiqin
1994, 18(5): 443-447.
We analyse the data of charmonium/bottonium suppression in P-A processes by considering the gluon shadowing effect at small x and the final-state interactions in the target nucleus. An empirical parametrization of the shadowing effect of the gluon structure function is used. The A- and x2-dependence of the suppression in P-A collisions is well obtained based on above physical consideration.
Chen Xingqu, Xing Zheng
1994, 18(5): 448-453.
Superdeformed bands in 193Tl are analyzed by means of the triaxial-particle-rotor model. An overall and excellent agreement between the calculated and observed spectra Er, kinematic moment of inertia and dynamic moment of inertia is obtained. The calculated B(M1) and dynamical quadrupole moments Q(1) and Q(2) are given. It is pointed out that the particle-rotor model can be used to analyze the superdeformed bands in nuclei.
The Effect of Symmetry on Structures And Internal Motions of a 4-Body System
Ruan Wenying, Bao Chengguang
1994, 18(5): 454-459.
The Schrodinger equation of a 4-body model system has been solved by using harmonic oscillator product states. The distribution of the wave functions and the shape-density functions in the multi-dimensional coordinate space has been investigated. A comparison has been made among the structures and internal motions of the totally symmetric states 0+, 0 and totally antisymmetric states 0+, 0. The effect of symmetry has been discussed.
A Semi-Microscopic Optical Potential Between 4N Nuclei with Same Masses
Zhou Quanhua, Gao Chengqun, Yang Baosheng
1994, 18(5): 460-465.
In the framework of the LCNO theory, a semi-microscopic optical potential for the 16O+16O system has been obtained by considering the quasi-molecular structure of this system and by using the wave function of the independent α-particle model. This potential has been used satisfatorily to reproduce the gross resonant structure in the elastic excitation function of the 16O+16O system.
Spin Effect of Antiprotou-Nucleus Inelastic Scatterings at Intermediate Energies
Li Yangguo
1994, 18(5): 466-472.
The antiproton optical potential at intermediate energies is obtained by the multiple scattering theory. The distorted wave of the antiproton is obtained by this optical potential which includes the spin-orbit interaction terms. In the framework of the distorted wave approximation, we discuss the differential cross section and polarization of antiproton-nucleus inelastic scatterings at intermediate energies. the and Pf(θ) of 12(P,P')12C*,2+,3- states at antiproton energies from 180 MeV to 508 MeV are calculated. It is shown that the theoretical results fit the experimental data at E=180 MeV quite well, and the theoretical results of and Pf(θ) at higher energies are predicted.
Effects of Positive-Parity States Octupole Correlations for Even-Even Nuclei in Rotational Regions
Qian Chengde
1994, 18(5): 473-480.
Within the framework of the Usdpf (16) interacting boson model, effects of theoctupole degree of freedom p-and f-bosons on the positive-parity states of even-evennuclei in rotational regions are discussed. It is shown that configurations of an evennumber of p-and f-bosons not only can be incorporated into the usual ground stateband, β- .γ-vibrational bands, but also naturally form the Kπ=1+.3+ rotational bandsetc. This result is similar to that of the Usdg (15)-IBM. Besides, E2 transition probabilities are discussed briefly.