1996 Vol. 20, No. 1

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Study of Energy Response Nonlinearity of BSC at BES
Chen Hongfang, Chen Shaomin, Chen Xiangyang, Gu Weixin, Lu Feng, Li Yong, Li Peiqin, Li Weiguo, Que Youkun, Mao Zepu, Tong Guoliang, Wang Linzhou, Wu Yigen, Xu Mingkang, Ye Shuwei, Ye Shizhang, Yi Kai, Zhang Yu, Zhou Yuehua, Zhou Li
1996, 20(1): 1-7.
The energy response characteristics of the barrel shower counter (BSC) of BES in energy region of J/ψ and Ds has been analysed,and a good energy linearity of BSC successfully obtained after eliminating the overlapping effect of the deposited energies in BSC of electrons and radiative photons.This demonstrates that the energy linearity of BSC is credible.
Emission Time Measurements of Light Particles from 40Ar+197Au Collisions in Intermediate Energies
He Zhiyong, Duan Limin, Li Zuyu, Jin Genming, Luo Qingzheng, Wu Heyu, Zhang Baoguo, Wen Wanxin, Qi Yujin, Dang Bingrong, Dai Guangxi
1996, 20(1): 8-12.
Particle-particle correlation functions have been measured for 40Ar+197Au collisions at E=25 MeV/u.Emission time of light particles has been extracted from correlation functions using the three-body trajectory model.The average emission time varies with the energy of particles. It decreases from about 300 fm/c for low energy particles to about 100fm/c for energetic particles.
Study of Recoil Properties of Target Residues From the Interaction of Copper With 20─46MeV/u 12C Ions
Wu Dingqing, Li Wenxin, Sun Tongyu, Sun Rulin, Zhao Lili, Zhang Fengshou, Yin Xinmin, Jin Genming, Li Ze, Jing Kexing, Li Xinhua
1996, 20(1): 13-20.
By using off- line γ-ray spectroscopy in conjunction with thick target-thick catcher foil techniques,the mean forward recoil ranges have been measured for the residues produced from interaction of copper with 20—46MeV/u 12Cions.From these data,linear momentum transfer for central collisions has been extracted. The linear momentum transfer per incident nucleon attains a maximum value of 155MeV/c at approximately 27.5MeV/u.The maximum excitation energy of the composite system is found to be 2.5MeV/u.
Production of Hafnium Isotopes From interactions of natW With 6.3─24.6 MeV/u 40Ar Ions
Zhang Xiang, Li Wenxin, Sun Tongyu, Yin Xinmin, Qin Zhi, Zhao Lili, Wu Dingqing, Zheng Jiwen, Liu Guoxing
1996, 20(1): 21-25.
The yields of known hafnium isotopes produced in 6.3-24.6MeV/u 40Ar+natW reactions were determined by γ-ray spectroscopy following radiochemical separations.The excitation functions,FW values and isotope distributions of hafnium were obtained.It is indicated that synthesis of new heavy neutron-rich isotopes is possible through the reactions induced by heavy ions at HIRFL energy region.The thick target is favorable for increasing the yields of neutron-rich nuclides far from the β-stability. However, further increasing incident energy is not always helpful to synthesize neutron-rich isotopes.
Muon Sample Selection from Cosmic Ray Events for BES
Gu Jianhui, Yu Zhongqiang
1996, 20(1): 26-31.
A big muon sample with wide momentum range is obtained by a time correction procedure applying to cosmic ray events collected by Beijing Spectrometer.The sample has been used in Ds Physics analysis.
Study of Stretched States Populated by 56,57Fe,59Co(α,d)58,59Co,61Ni Reactions
Yuan Jian, Lu Ming, Lu Daoru, Chen Quan, Sun Zuxun
1996, 20(1): 32-37.
Spectra and angular distributions of the(α,d)reactions on 56Fe 57Fe and 59Co have been measured with the △E-E telescopic systems and Q3D magnetic spectrometer at a bombarding energy of 35MeV from the HI-13 Tandem,and analyzed with microscopic DWBA.Among the angular distributions of nine levels strongly populated by 56Fe(α,d)58Co reaction, the experimental data of 6.79MeV and 6.4MeV levels in 58Co were analyzed and discussed. The highest stretched configuration (1g9/2,1g9/2)9 was found and Jπ=1+ of 6.4MeV level was determined for the first time. No isolated stretched states were observed by 57Fe 59Co(α,d)reactions.This probably means that the strength of the stretched configuration spreads on a number of states.
A Two-Parameter Deformed Two-Dimensional Interacting Boson Model With Uqp(U3)Uqp(U2)Uqp(SO2) Symmetry
Zhou Huanqiang, Guan Xiwen, He Jingsong
1996, 20(1): 38-44.
A two-parameter deformed two-dimensional interacting boson model with Uqp(U3) Uqp(U2) Uqp(SO2)symmetry is constructed.It is found that the energy spectrum and transition matrix elements depend very sensitively on the second parameter of deformation.
Determining the Spin-Parity of the Boson Resonance X in the Process J/ψ→X+f0 (980) by Using the Generalized Moment Analysis Method
Shen Qixing, Yu Hong
1996, 20(1): 45-47.
The processes J/ψ→X+f0 (980), X→K+ K,f0 (980)→π+ are discussed using the generalized moment analysis method. It is suggested that in terms of the obtained moment expressions the spin-parity of the boson resonance X can be determined by further measurements.
Constrained Correlation Dynamics of QED in Canonical Form(Ⅰ) Equations of Motion for Correlation Green's Functions
Guo Hua, Wang Shunjin
1996, 20(1): 48-54.
With the aid of generating-functional technique and in the framework of correlation dynamics,we establish the constrained correlation dynamics of QED in the temporal gauge and canonical quantization form,and obtain a closed set of equations of motion for correlation Green's functions.
Analytic calculation of Glueball Mass In (2+1)-D SU(2)Lattice Gauge Theory
Hui Ping, Cai Pengfei, Chen Qizhou
1996, 20(1): 55-60.
In this paper,the glueball mass of 0++ is calculated in the (2+1)-D SU(2) lattice gauge theory with connection graphs.The result shows a good scaling behavior.
Probability of e+e Annihilation in High Energy Collision and Intermittency
Wang Zhengzhi
1996, 20(1): 61-64.
Charged particle multiplicity distributions for e+e annihilation are shown to be very well described by a negative binomial distribution in high energy collisions.The factorial moments F2,F3 and F4 are given in terms of 3k.
An Analytic Study of Self-affine Fractal in Two-Dimensional Phase Space of High Energy Collisions
Lin Hai, Zhang Yang, Liu Lianshou
1996, 20(1): 65-75.
The self-affine α-model in 2-dimensional phase space is discussed in some detail.The analytic expression of the normalized probability moments,C2N and C3N,are deduced for the self-similar analysis of a self-affine fractal object with Hurst index equal to 0.5.The Levy stability indices for both the self-similar and the self-affine analyses of 2-D self-affine model are calculated. The result of Monte Carlo simulation is shown to be consistent with that of analytic calculation.The recent experimental data from NA22 collaboration are explained qualitatively.
Vibrational and Rotational Motions Model of Nucleus(Ⅰ) Cranking Bohr-Mottelson Hamiltonian and Analyses of the Rotational Bands of Even-Even Nuclei
Hu Jimin, Xu Furong, Zheng Chunkai
1996, 20(1): 76-84.
Starting from cranking shell model,a collective vibrational and rotational Hamiltonian(cranking Bohr-Mottelson Hamiltonian CBMH)is derived,in which the rotational frequency is not quantized.Introducing a reasonable collective potential,the formula for the rotational spectrum can be obtained.The formula is applied to analyze the rotational bands of even-even nuclei with satisfactory results.
Studies of the Low-Lying States in 157,159Tm
Xing Zheng, Chen Xingqu, Xu Shuwei
1996, 20(1): 85-91.
Properties of the low-lying positive-parity states in 157,159Tm are investigated ly using the triaxial rotor plus particle model with the variable moment of inertia (VMI) of the core.The good agreement between theory and experiment shows that 157Tm and 159Tm may be triaxiality.Furthermore,it is suggested that an excitation rotational band in 157Tm probably already exists in the experimental data.
Effect of Symmetry on Structure of 3-Fermion Systems With Spin S=1/2
Xie Wenfang, Bao Chengguang
1996, 20(1): 92-96.
A 3-fermion system with spin S=1/2is examined.It is found that the quantum mechanical symmetry plays a decisive role in determining microscopic structures.