1996 Vol. 20, No. 10

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The Deformation-Driving Character of the 1/2[541] Orbit in 171Lu
Ma Yingjun, Zheng Hua, Sun Huibin, Yang Hongting, Zhou Shangui, Ding Yougui, Huo Junde, Liu Yunzuo, Liu Xiangan, Wen Shuxian, Yang Chunxiang
1996, 20(10): 865-869.
The 1/2-[541] band in 171Lu is extended up to neutron crossing by using heavy-ion induced reaction 160Gd(19F, 6n2p) at a bombarding energy of 92MeV.It shows delayed neutron crossing frequency in comparison with the even-even neighbors.Calculations based on cranked shell model suggest that the role played by the deformation-drving effect of the πh9/2[541]1/2 orbit shouldn't be ignored in the delay of the bandcrossng in 171Lu.
Fourfold Fragmentation in Hot Nuclei
Dai Guangxi, Wu Heyu, Luo Qingzheng, Duan Limin, He Zhiyong, Zhang Baoguo, Li Zuyu, Wen Wanxin, Qi Yujin
1996, 20(10): 870-876.
Experimental results of fourfold fragmentation of single hot nucleus are reported.Distributions of mass,velocity,correlation angles between fragments and emission probability versus mass of fragments are studied.
Solar Flares and Solar High Energy Particles
Zhang Li, Dai Benzhong, Mu Jun
1996, 20(10): 877-884.
Generally,the solar high energy particles in the flares are believed to be accelerated in two stages:acceleration by abrupt release of magnetic energy in the first stage and coronal diffusive shock wave or stochastic acceleration in the second stage.In this paper,we consider the diffusive shock wave acceleration in gradual solar flare associated with fast coronal shock wave. The results indicate:(1) the characteristics of the particle distribution with time depends on the momentum and with the incresing of transition time,the distribution increases to maximum quickly and turns to decrease them the higher energy,the more time of moving to maximum;(2)the corresponding time integral spectrum is proportional to the power of the particle momentum.The possibility of accelerating particles to high energy range is also discussed.
Single Photon Time Spectra in Gas Avalanches
Han Jiaxiang, Xu Zizong, Chen Hongfang, Li Cheng, Zeng Hui
1996, 20(10): 885-889.
Using the technology of the single photon time resolution, we have studied the time spectra of light emission in LP mode, SQS mode and G-M mode. The results show that the SQS streamer has a delay relative to the primary avalanche and its lasting time is about 10—30us which depends on the contents of the quenching gas and the anode high voltage.The lasting time in the G-M mode is about lμs,and that in the LP mode is only 4ns.This has fully demonstrated that the three modes have quite different characters in their individual avalanches.
Experimental Studies on Using Silicon Photodiode as Read-out Component of CsI (Tl) Crystal
He Jingtang, Chen Duanbao, Li Zuhao, Mao Yufang, Dong Xiaoli
1996, 20(10): 890-893.
In this paper, experimental studies on using silicon photodiode as the read-out component of CsI(Tl) Crystal are reported.The read-out properties of two different types of silicon photodiode produced by Hamamatsu were measured, including relations between energy resolution and bias,shaping time, sensitive area of photodiode and the dimension of the crystal.
A Discussion About Recent Numerical Results From the Calculation of the Glueball Masses on Lattice Gauge Theory
Wu Jimin
1996, 20(10): 894-899.
We analyse recent numerical results from the glueball masses calculation on lattice and its implication to the J/ψ,ψ decay experiments.
A Quark Model Including Lepton Structure
Liu Yaoyang, Jiang Xiangdong, Zhou Jiange
1996, 20(10): 900-912.
The chiral extension of the standard model makes quarks having two chiralities parallelly.Some interesting questions, such as the possibilities of leptons being made of additional leptonic quarks and proton decay, are discussed.We also investigate the supersymmetrization of the extension of quark model.It is proved that such a theory maintains many important characteristics of the original one, but the generation number required for breaking asymptotic freedom is decreased from >33/8 to>9/4 which is compatible with the present experiments.
Reestimate for CP Asymmetries in Decays of Neutral B-Flavored Mesons
Zhu Guohuai
1996, 20(10): 913-918.
The CP violating effects in partial-decay-rate asymmetries of the Bd0 and Bs0 systems are reestimated with the method of amplitude ratio. We concentrate on those hadronic final states which are CP eigenstates. We find that for testing CP violations,except the well known Bd0→ψKs, the best decay is Bd0→D+D, which needs, for 3σ signature, 2.2×107 bb pairs.
Rapidity Distribution of Various Charged Hadrons in High Energy Nucleus-Nucleus Interactions
Feng Shengqin, Wang Zhengqing
1996, 20(10): 919-924.
In this paper, we analyse the various charged hadron distributions given by E-802 Collaboration at BNL/AGS in terms of thermalization model, which considers the fluctuation of impact parameter and stopping power of nucleus in the center-of-mass frame of participants.
In-medium Nucleon-△Scattering Cross Sections
Mao Guangjun, Li Zhuxia, Zhuo Yizhong
1996, 20(10): 925-931.
The medium effects on the nucleon-△ elastic and inelastic scattering cross sections are investigated within the framework of self-consistent relativistic Boltzmann-Uehling-Uhlenbeck approach. The results show that at SIS energy range the in-medium cross sections deviate substatially from the Cugnon's parametrization.So, the medium effects must be taken into account.
Interaction Potential Between Heavy Ions in Fusion Reactions
Hu Jimin, Zhong Yunxiao
1996, 20(10): 932-936.
The interaction potential between several pairs of heavy ions are calculated in both sudden and adiabatic approximations with the Skyrme force. Fusion reaction cross-sections are calculated and compared with experimental results.
Nonperturbative Effect of Nonstrange Baryonic Spectrum
Chen Hong, Zhang Zongye
1996, 20(10): 937-944.
We study N and △ spectra by solving Schrodinger equation for the three quark system in the mixture of configurations. Besides the perturbative effect of usual one-gluon exchange, the nonperturbative effects of both color screening predicted by the LGT calculation and pion(sigma) exchange due to the chiral symmery breaking are also included in present quark-quark potential. The agreement of the baryonic spectra obtained with the experiment is improved.
Microscopic Calculation of Nucleon-Nucleon Cross Section in Nuclear Medium Within BHF Approach
Cai Yanhuang, Song Hongqiu
1996, 20(10): 945-949.
Within the framework of Brueckner-Hartree-Fock (BHF) method, the total inmedium N-N cross section is calculated. A separable Paris potential for the N-N interaction and a continuous choice for the single particle spectrum are used. It is found that the in-medium cross section is strongly modified with increasing nuclear density, in particular at low energy. Some discussions and comparisons are also given.
Research of Bunch Lengthening of BEPC Ring by Many-Particle Simulation
Li Yun, Wang Guangwei
1996, 20(10): 950-956.
By many-particle simulation, longitudinal instability of BEPC ring is analysed and dependence of bunch length on single beam current and the threshold current are given.Simulation results go well with the measurement results.
A New Working Mode for ECR Source
Liu Zhanwen, Zhang Wen, Zhao Hongwei, Yuan Ping, Zhang Xuezhen, Guo Xiaohong, Li Xixia, Zhou Sixin, Wang Yifang, Wei Baowen
1996, 20(10): 957-960.
In this paper a new working mode for ECR2 ion source of Heavy Ion Accelerator in Lanzhou is introduced The operating conditions, particular feature and the output of high charge state ions in this condihon are described. Some discussions on the new mode are also given.