1990 Vol. 14, No. 11

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Review
STUDY ON SUPERHIGH ENERGY γ-RAY FAMILY EVENTS WITH LARGE-SCALE Fe EMULSION CHAMBERS
REN Jing-Ru, LU Sui-Ling, SU Shi, HUO An-Xiang, WANG Cheng-Rui, ZHANG Nai-Jian, HE Mao, CAO Pei-Yuan, LI Jin-Yu, WANG Shi-Zhi, LI Guang-Ju, BAI Guang-Zhi, LIU Zhong-He
1990, 14(11): 961-965.
Abstract:
Using a large-scale iron emulsion chamber,a big γ-ray family event with observed energy ΣEγ=7631TeV was obtained.This paper described the advantages of iron emulsion chamber for studying big families and the characteristics of the event observed,together with a comparison with the Monte-carlo simulation results.
π-μ IDENTIFICATION AND HADRON CALORIMETER ANALYSIS OF ALEPH EXPERIMENT WITH MULTIVARIATER STATISTICS METHOD
XIE Yi-Gang, JIN Shan, HUANG Xiu-Ping
1990, 14(11): 966-972.
Abstract:
In this paper π-μ identification of the hadron calorimeter prototype and the real hadron calorimeter with muon detector of ALEPH experiment on LEP is investigated by using discriminant analysis method of multivariate statistics.
THE FLUID THEORY OF SELF-SUSTAINING MAGNETICALLY CONFINED ELECTRON CLOUDS (Ⅰ) FLUID EQUATIONS
YU Qing-Chang
1990, 14(11): 973-979.
Abstract:
In this paper the axisymmetrical self-sustaining magnetically confined electron clouds are studied by means of the fluid theory.In the electron clouds which supported by the Penning discharge the property of motion of electrons can be described by the fluid equations:continuity equation,momentum equation,energy equation,Poisson equation and heat transfer equation.The problems of the diffusion and escape of electrons and the energy transport in the electron clouds are discussed.
CHIRAL PHASE TRANSITION IN A MODEL WITH DYNAMICAL SPONTANEOUS-SYMMETRY-BREAKING AT FINITE TEMPERATURE AND DENSITY
WANG En-Ke, LI Jia-Rong
1990, 14(11): 980-990.
Abstract:
The chiral-symmetry-restoring phase transition in a model with dynamical spontaneous-symmetry-breaking is discussed qualitatively,making use of an approximation method.The selfconsistency equation of the model is established.The condensation and mass of fermions as well as the temperature or density dependence of energy density and specific heat are obtained.It turns out that,in this approximation,the chiral-phase-transition is second order at zero chemical potential and finite temperature; and the transition is first order for both cases at finite temperature and density and at zero temperature and finite density,this moment.the transition temperature or density from broken phase to normal phase differs from that from normal phase to broken phase.
BJORKEN-JOHNSON-LOW TECHNIQUE AND PERTURBATION STUDY ON CHIRAL ANOMALY IN ABELIAN COSET PURE GAUGE FIELD THEORY
JING Si-Cong, RUAN Jie
1990, 14(11): 991-1000.
Abstract:
The perturbation theory in coset pure gauge field theory is studied for the first time in this paper.By using the Bjorken-Johnson-Low technique and calculating the Schwinger term in related commutators,the anomalous Ward identity in Abelian coset pure gauge field theory is derived,which is consistent with the non-perturbative calculation.
THE FRAGMENTATION OF GLUON OF GLUON IN e+e ANNIHILATION
LIU Xi-Ming, WU Hua-You
1990, 14(11): 1001-1006.
Abstract:
In this paper,we suggest that the gluon is hadronized by first splitting into a quark-anti-quark pair.The final hadrons are produced by the color interactions among the quarks and antiquarke.By this assumption,the calculated average charged particle multiplicities in e+e→3jet events,and the ratio of multiplicities between gluon and quark jet,and the rates of baryons in e+e three gluons events all agree well with experiments.The angle distribution of final particles can be explained.
LOW-LYING RESONANCE IN CHIRAL MESON-QUARK MODEL
YANG Ke-Yan, XIA Ke-Ding
1990, 14(11): 1007-1013.
Abstract:
The quantum fluctuations of the chiral Meson-Quark Model is formulated and the mesonhedgehog baryon scattering phase shift is calculated.It is found that the chiral Meson-Quark Model is stable against small oscillations and the resonance exists.The calculated resonance width is consistent with experimental data,but the resonance energy is only half of the experimental data.
A SYSTEMATIC DISTORTED WAVE IMPULSE APPROXIMATION ANALYSIS OF THE CONVENTIONAL MECHANISM FOR PION DOUBLE CHARGE EXCHANGE
PAN Ling-Jun, JIANG Huan-Qing, ZOU Bing-Song
1990, 14(11): 1014-1022.
Abstract:
In the framework of the distorted wave impulse approximation,a systematic analysis is performed for the contribution from the conventional mechanism to the double charge exchange to the double isobaric analog state.The effects of distortions of pions,nuclear wave functions,short-range correlation functions,parameters of form factors,the spin-dependent term in the πN amblitude etc.are examined.It is shown that all these elements are very important and not negligible for the conventional mechanism.But after including the effects of all these elements,the conventional mechanism is still not able to reproduce the experimental excitation function and agular distribution for the energy region of 0—300MeV,therefore the effects of some other mechanisms should be included.
CROSS SECTION MEASUREMENTS OF NUCLEAR REACTIONS FOR Ni INDUCED BY 14MeV NEUTRONS
LI Guo-Zheng, JIANG Jing-He
1990, 14(11): 1023-1030.
Abstract:
The cross sections of reactions 58Ni(n,2n)57Ni,58Ni(n,p)58mCo,58Ni(n,p)58gCo and 58Ni(n,p)58m+gCo were measured based on 27Al(n,a) 24Na reaction by activation methods.Incident neutron energies were 14.10MeV and 14.62MeV.A comparison was made between present results and other published data.The cross sections for 58gCo nuclei formation are given for the first time.
SINGLE-PARTICLE AND SINGLE-HOLE ENERGIES IN THE 40Ca REGION
DOU Zhi-Guo, JING Xiao-Gong, ZHAO Guo-Quan
1990, 14(11): 1031-1038.
Abstract:
The single particle (SP) energies of 41Ca and the single hole energies of 39Ca are calculated with eigenvalue equation derived from SP Green's function.The matrix element of M-3Y force is adopted as the equivalent of G-matrix element.Two particle one hole (2plh) and two hole one particle (2hlp) multiple scattering (MS) correlation were studied.The results show the 2hlp MS correlation is more important than the 2plh MS correlation.
ON THE BACKBENDING MECHANISM OF MUITIBAND STRUCTURE IN NUCLEUS 185Pt
ZHANG Jing-Ye
1990, 14(11): 1039-1044.
Abstract:
The observation of multi-band structure in nucleus 185Pt reported recently,once again raises the open question about whether the alignment of proton h9/2 pair or neutron i13/2 pair should be responsible to the backbending in five band.Blocking experiments prefer the proton h9/2 pair while the Total Rothian Surface calculation supports neutron i13/2 pair.Based on the analysis of assumptions implied in both approaches,a new theoretical calculation which includes the dynamic effect of band crossing is presented.Such a calculation indicates that the alignment of proton h pair should be the main cause for the observed backbendings.
HEAVY ION COLLISION DYNAMICS IN FERMI DOMAIN (Ⅱ) DYNAMICS DEPENDENCE OF IMPACT PARAMETER
ZHANG Feng-Shou, GE Ling-Xiao
1990, 14(11): 1045-1050.
Abstract:
The peripheral collision mechanisms have been systemic ally studied via the Boltzmann-Uehling-Uhlenbeck theory in the Fermi domain for 20Ne+20Ne collision system.The characters of energy dependence and the intermediate mass fragment production in the process of incomplete deep inelastic collision were discussed.
A STUDY OF EXITATION ENERGIES SHARING BETWEEN FRAGMENTS IN HEAVY-ION REACTIONS
WANG Zheng-Da
1990, 14(11): 1051-1056.
Abstract:
In this paper the excitation energies sharing between fragments in heavy-ion reaction were analysed based on Coherent Surface Excitation Model (CSEM) For 56Fe+238U at ELab=476MeV and 86Kr+208Pb at ELab=1565MeV reactions,a comparison between experimental data and calculated values has been made.