1992 Vol. 16, No. 8

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Fine Measurements of Beamilne 3B1 at Beijing Synchrotron Radiation Facility
CUI Ming-Qi, LIU Li-Bing, XU Wen-Xuan, WU Jian-Wu, WANG Pei-Wei, YI Fu-Ting, GU Xiang-Ming
1992, 16(8): 673-678.
At the dedicated mode (the storage ring Ee=2.0GeV) of BEPC,we measured the intensity and the spectra of Beamline 3B1 at Beijing Synchrotron Radiation Facility (BSRF) for different closed orbits.The optimum photon intensity and the optimization of operation condition for Beamline 3B1 were given in this paper.The results of measurements for energy spectra at different states were given and analysed also.
Light Source for Synchrotron Radiation X-Ray Topography Study at Beijing Syncrotron Radiation Laboratory (BSRL)
ZHAO Ji-Yong, YANG Ping, JIANG Jian-Hua, TIAN Yu-Lian, HAN Yong, WANG Chun-Xi, SHI Cai-Tu, XIAN Ding-Chang
1992, 16(8): 679-684.
Characteristics of the synchrotron radiation source for X-ray topography study at Beijing Synchrotron Radiation Laboratory (BSRL) is desribed in this paper,local geometrical resolution of topographs is discussed,the diffracting intensities of white beam topography is given.
Fermion Condensates in Lower Dimensional Gauge Theories
LUO Xiang-Qian, CHEN Qi-Zhou
1992, 16(8): 685-695.
Combining a unitary transformation,the variational method and the exact ground state of pure gauge Hamiltonian.we investigate syst matically the vacumm structure and spintaneous chiral-symmetry breaking in (1+1) and (2+1) dimensional Hamiltonian lattice gauge theories with fermions,and obtain nice scaling behaviors for 〈ψψ〉 extending to the weak coupling regime.This paper not only reproduces well the exact value in the continuum Schwinger model,but also predicts the values for the fermion condensates in QCD2,QED3 and QCD3.
Hamiltonian Formalism of WZNW Field Under Chevalley Basis
YANG Huan-Xiong
1992, 16(8): 696-703.
The Hamiltonian canonical formalism of two dimensional WZNW theory based on arbitrary semi-simple Lie algebras is given under Chevalley basis.The Poisson brackets of conserved chiral currents are calculated,which turn out to be the classical Kac-Moody current algebras.
Angular Distributions and Generalized Moment Analysis for the Doubly Radiative Decay J/ψ→γγV
SHEN Qi-Xing, YU Hong
1992, 16(8): 704-715.
The doubly radiative decay process J/ψ→γ+X,X→γ+V,V→2P(or 3P) is discussed in this paper.For the intermediate state X with various spin-parity JP,the corresponding helicity formalism of angular distribution formulas and the moments developed from the generalized moment analysis are presented.They are helpful for determining the spin of the intermediate state.
Mass Splittings of L=1 States of Quarkonium and Lorentz Structure of Long-rang Confinement Potential
LUO Zhen-Fei, QIU Xi-Jun
1992, 16(8): 716-722.
The Lorentz nature of linear confinement potential of quarkantiquark pair is analyzed in the potential model by using the fine mass splittings of L=1 spin triplets in cc and bb systems.It is found that the linear confinement potential has a mixed nature of the Lorentz scalar and vector (0≤η≤29%,η=0 represents the pure Lonentz scalar).For the tentatively measured χ(11P1) and γ(11P1) meson masses,it is shown that the pure Lorentz scalar of the linear confinement potential is required to obtain the mass of the former meson,while the mixture of 79% Lorentz scalar and 21% Lorentz vector is required to explain the mass of the latter one.
Bag Constant and Deconfinement Phase Transition in the Nontopological Soliton Bag Model
GAO Song, WANG En-Ke, LI Jia-Rong
1992, 16(8): 723-730.
The effective potential in finite temperature and density nontopological soliton bag model is investigated.Based on this,we calculate the bag constant which depends on temperature and chemical potential.We also analyse the property of deconfinement phase transition.
Measurement of Some (n,2N) Reaction Cross Sections for Producing Long Half-Life Residues
WANG Yong-Chang, YUAN Jun-Qian, YANG Jing-Kang, KONG Xiang-Zhong, REN Zhong-Liang, WANG Hua-Min
1992, 16(8): 731-735.
Measurement of (n,2n) reaction cross sections for some nuclides,whose residues have long half-lives,is described.The activation method relative to the 93Nb(n,2n)92mNb reaction cross section was used.The cross sections of the 151Eu(n,2n)150mEu、153Eu(n,2n)152Eu、159Tb(n,2n)158Tb and 109Ag(n,2n)108mAg reactions in the neutron energy range of 13.50—14.80MeV were measured.The neutron energies in this experiment were determined by means of the method of cross section ratios for 90Zr(n,2n)89m+gZr and 93Nb(n,2n)92mNb reactions.The results obtained were compared with other existing data.
Nuclear Excitation by Electron Transition and Gamma-Ray Laser
HUO Yu-Kun, ZHANG Bao-Hui, YUAN Zhu-Shu
1992, 16(8): 736-742.
This paper studies nuclear excitation by electron transition (NEET) and is potential application in developing gamma-ray laser.A quantum mechanics formula to calculate NEET probabilities was presented with emphasis on the calculations of the transition matrix elements and discussions of the transition selection rules.The NEET probabilities for a number of nuclides were calculated.The upper limit of NEET probability is evaluated to be about 10-5.The possibility for applying the technique of NEET in the development of gamma laser was investigated.
The Algebraic Method to Solve the Fission F-P Equation
LING Yin-Sheng
1992, 16(8): 743-748.
Using Lie algebraic method to solve the time evolution equation.The integration formula of the fission F-P equation in the harmonic potential is obtained.This method can be used to deal with the variable coefficients cases.
Impact Parameter and Bombarding Energy Dependence of Collective Flow in the Dynamics Process of Intermediate High Energy Heavy Ion Collision
YANG Fu-Zhong, LIU Jian-Ye
1992, 16(8): 749-753.
The time processes of collective flow were calculated by use of BUU equation with momentum dependence mean field and nucleonhucleon collisions in medium.It is shown that the momentum dependence mean field effect and the medium effect on the collective flow are obvious and sensitive to impact parameter and bombarding energy.
Microscopic Mechanism of the Variation of the Ground Band Moments of Inertia with Neutron Numbers in 166—176Yb
ZHAO Zheng-Ji, JIN Tai-Hao
1992, 16(8): 754-761.
Using the particle-number-conserving (PNC) method,the microscopic mechanism of the variation of the ground band moments of inertia with neutron numbers in 166—176Yb is investigated in the cranked shell model (CSM).The K-structure and seniority structure of the PNC CSM wave function are analyzed carefully.The distribution of the low-lying high-j intruder pair-broken (v=2)Kπ=1+ configurationsplays a crucial role for the magnitude of the ground band moments of inertia.
A Comparison Between two Different α-Particle Wave Functions via Heavy ion Scattering
YANG Yong-Xu, LI Qing-Run
1992, 16(8): 762-764.
The independent α-particle model wavefunction and the wavefunction with the simple Gaussain form are tested by means of the heavy ion scattering.The experimental data obviously support the former but are unfavorable to the later.
New Neutron-Rich Nuclide 185Hf
YUAN Shuang-Gui, ZHANG Tian-Mei, PAN Qiang-Yan, ZHANG Xue-Qian, XU Shu-Wei
1992, 16(8): 765-766.
New neutron-rich nuclide 185Hf has been identified for the first time.The 185Hf was produced via the 186W(n,2p)185Hf reaction by 14MeV neutron irradiation of natural metallic tungsten powder and separated by radiochemical methods.The identification of 185Hf was based on the observation of decay γ-ray of its daughter 185Ta.A half-life of 3.5±0.6min was determined for 185Hf by fitting the measured growth and decay curve of the 177.59keV γ-ray which is the strongest decay γ-ray of 185Ta.In addition,a new γ-ray of 164.5±0.5keV was found and assigned to 185Hf.
New Neutron-Rich Isotope 208Hg
ZHANG Li, JIN Gen-Ming, ZHAO Jin-Hua, YANG Wei-Fan, YANG Yong-Feng, ZHAO Zhi-Zheng, ZHENG Ji-Wen, SUN Xiu-Rong, LI Zong-Wei, QIN Zhi, WANG Ji-Cheng, GUO Guang-Hui
1992, 16(8): 767-768.
The new neutron-rich isotope 208Hg has been identified for the first time from the reaction products in fully-stopping thick nat.Pb target bombarded by 30MeV/u 12C beam provided by the Heavy Ion Research Facility in Lanzhou.Assignment of the nuclide 208Hg was based on the measurements of the deacy γ energy and halflife of its daughter 208Ti,which was grown up with 208Hg β-deacy.The half-life of 208Hg β-deacy was determined to be 42+23-12 min.The average production cross section of 208Hg over the incident energy region from Coulomb barrier to 30MeV/u is found to be 1.1±0.5μb.