1991 Vol. 15, No. 5

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The Measurement of Bunch Length of Beijing Electron Positron Collider
LI Jin, MAO Ze-Pu
1991, 15(5): 385-390.
The method of determining the bunch length of collider by the vertex of charged particles which came from J/ψ decay is discussed.The bunch length of Beijing Electron Positron Collider at colliding region is presented.
Dynamics Calculation in a L-band Travelling Wave Electron Linac
ZHANG Zhen-Hai, SONG Zhong-Heng
1991, 15(5): 391-398.
The PARMELA code is modified for three-dimensional dynamic calculation of the injector of a L-band travelling wave electron linac for FEL research.Various parameters in relation to characteristics of the beam are given in the paper.
Electron-Positron Condensate and Non-Topological Soliton Model in the Strong-Coupling Phase of QED
SHEN Kun, QIU Zhong-Ping
1991, 15(5): 399-404.
The dynamics of condensate formation is investigated in the nontopological soliton model,and the critical coupling constant gcrit and critical charge number of nucleus Zcrit are obtained.Many salient features of the narrow e+e peaks can be understood within the framework of the new phase of QED,which indicates that electron-positron condensate plays an important role in the strong-coupling phase of QED.
Constraints to Grand Unified Preon Models from Recent Lep data
BAO Shu-Qing, XUE Xiao-Zhou
1991, 15(5): 405-413.
Constraints to grand unified preon models from recent LEP data on light neutrino species Nv are analyzed.Because the precise experimental result prsult prefers Nv=3,the possible grand unified preon models are grand unified preon models with confining weak interaction.So the weak interaction is confining and is the residual effect of the hypercolor interaction between preons.The constraints to grand unified preon models from the very heavy neutrinos being allowed is also discussed.
The World Sheet Soliton and free energy on High Genus Riemann Surface
YAN Jun, HU Shi-Ke
1991, 15(5): 414-419.
The free energy on high genus Riemann surface has been calculated by using the world sheet soliton action.This soliton-like action is corresponding to the bosonic string coupled to the two-dimensional scalar field.
The Boson Bound States in the Higher Dimensional Kerr Metric
CAI Rong-Gen, CHEN Zhi-Jian
1991, 15(5): 420-426.
The radial wave function equation of bosons in higher dimensional Kerr metric is obtained with the separation of variables.The boson bound states around higher dimensional Kerr black hole are discussed.It is found the boson bound states do not exist in higher dimensional Kerr geometry.This conclusion is independent with the boson mass.
The Restoration of Symmetry and Plasmon Effects at High Temperature and High Density in the Weinberg-Salam Model
HOU De-Fu, LI Jia-Rong
1991, 15(5): 427-436.
The effective potential of the W-S model is calculated at finite temperature and Jensity from the entire Lagrangian according to the grand canonical ensemble temperature field theory.The two elementary thermal effects is the weak and electromagnetic system are studied.The result indicates that the thermal effects not only counteract the Higgs mechanism effect and make the symmetry restore,but also make the gauge particles leave nonvanishing masses due to the plasmon effects.
The One-Body Density and the Oscillation Mode of the Hypernucleus 9Be at Low-Lying States
LI Chu-Liang, LI Xun-Gui
1991, 15(5): 437-441.
The One-body structure and the internal oscillation mode of the hypernucleus 9Be at low-lying states have been determined by calculating the one-body density and the curves of r(R) at the conditional maximum of the shape density ρs.
The Experimental Terminal of Large Area Ionization Chamber at HIRFL Accelerator
FENG En-Pu, ZHU Yong-Tai, GUO Zhong-Yan, QIAO Wei-Min, ZHAN Wen-Long, SHEN Wen-Qing, WANG Xiao-Qiu, WANG Bing, YIN Shu-Zhi, FENG Jun, LIU Guan-Hua, XI Hong-Fei, FAN En-Jie, ZHU Xiang, ZHOU Jian-Qun, ZENG Yao-Wu
1991, 15(5): 442-449.
This report describes the general situations of the experimental terminal of large area ionization chamber which the HIRFL accelerator in Lanzhou.The basic structure of the terminal and detector systems is introduced.Some measurement results of the detectors are given.Some research objects with this terminal on reaction mechanisms at intermediate energy are also presented.
Evolution of Strangeness in an Expanding Quark-Gluon Plasma Formed by Ultrarelativistic Nucleus-Collisions
JIANG De-Bao, HE Ze-Jun
1991, 15(5): 450-456.
The evolution of strangeness in an expanding quark-gluon plasma formed by ultrarelativistic nucleus-nucleus collisions was studied by solving relaxation equations.In the calculation,the 3-dimensional expansion effect of the system was described by relativistic hydrodynamic equations.The temperature effect of the latent heat released by the phase transition on the evolution of strangeness was considered.
BUU Calculation With Momentum Dependent Mean Field
ZHANG Jian-Ming, GE Ling-Xiao, ZHANG Feng-Shou, ZHUO Yi-Zhong
1991, 15(5): 457-464.
With a Skyrme force the Momentum and density dependent mean field was calculated.The effects on the collective flow produced from heavy ion collision with and without the momentum dependent potential were discussed in the framework of BUU theory.
Hexadecapole Moments and Interaction between Nucleons of the Rotational Nuclei in the Rare-Earth Region
WANG Zhen, RONG Zhong-Lin, WU Hua-Chuan
1991, 15(5): 465-472.
By proton-neutron BCS method with very few parameters,Hexadecapole moments (Q40) and quadrapole moments (Q20) are calculated for even-even nuclei in the whole rare earth region.Some of the results are in good agreement with expriments.The comparison between calculation and experiments shows that quadrapole interaction strengths between same nucleons are just about one fifth of that between proton and neutron,which are very important for the explanation of the Q40 systematics.
A Harbour for Strong CP Problem——Heavy Quarks
WU Dan-Di, HUANG Zheng
1991, 15(5): 473-476.
Missing points in previous literature about strong CP are remarked.Emphasis is put on vacuum alignment with heavy quark taking into account.After obtaining the master equations of vacuum alignment,we point out that mCd=0 is the sufficient and necessary condition for =0,where m is the mass of a quark and Cd the dynamical condensate of the same quark.People have discussed the scenario with a vanishing u quark mass.We propose here a different scenario with Cd=0 where Cd is the dynamical condensate of a heavy quark.
The Polarization States of the Gluon and the Glueball Interpretation of the ξ(2230)
SHEN Qi-Xing, YU Hong
1991, 15(5): 477-480.
The giueball interpretation of the ξ(2230) is discussed when the gluon has only the transverse components.