1990 Vol. 14, No. 9
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A positron dislocation trapping model which considers the effects of positron detrapping from dislocations is given.The temperature dependence on α (the ratio between the number of positrons trapped directly from bulk into jogs and that of positrons trapped indirectly passing through the dislocation channel from bulk into jogs) and the initial temperature Ti that positrons are mainly annihilated at lislocation lines are discussed.
The main drift chamber of the Beijing Spectrometer (BES) has been described briefly,including its physical design,mechanical design and construction,choice of the working gas as well as prototyping.The performance of the chamber,experimental or expected,has been given:solid angle coverage,gain and efficiency,spatial resolution on the R-φ plane,axial spatial resolution,dE/dx energy resolution and particle identification power,etc.
In this paper we systematically analyse and generalize the Boson Realization Method proposed by the author for constructing indecomposable representations of Lie (super) algebras.We prove that the representations thus obtained cover the master representation of Gruber and point out the relation of its coset representation to the boson coherent states.We also propose a general method of finding the inhomogeneous differential realizations of lie algebras from their indecomposable representations,which is very useful in new found quantum mechanical quasiexactly solvable problems.
The contribution of internal fermion one-loop to the Casimir energy between two parallel conducting are calculated by using the Feynman path integral method.The force per unit area is 0.00025dyne/cm2.
In this paper,we explicitly drive the expressions of Fusion and Braid matrices in the minimal model,and show the solvability of D-F equation.
The chiral quark-soliton model with one gluon exchange is described simply in the present work,and the quark-gluon coupling constant and quark wave function,which are determined in this soliton model,are used to study two-nucleon system in the relativistic two-quark-cluster theory.Here kinetic energy and relative-motion energy terms are wholly considered in the quark-exchange kernel,therefore the phase shifts of 3S1- and 1S0- shannels are improved.Our phase shifts are in agreement with those obtained by Arndt et al.It is shown that the one-gluon-exchange and quarkexchange mechanism offers a short-range repulsive potential while the chiral field produces a middle and long range attractive potential.
Based on the analyses of the transverse energy distributions data measured by the HELIOS collaboration group on 16O-A collisions experiments at 200A GeV,the necessity of considering non-geometrical effects in target fragmentation is pointed out,and these effects are described equivalently by the fluctuation of the number of participating nucleons in the framework of geometrical model.
The details of the one loop on-mass-shell renormalization of the chiral σ model in nuclear matter are given.The nucleon energy density in nuclear matter is calculated and the results are compared with that of the zero point renormalization scheme.
The angular distributions of fission fragments and the excitation functions have been measured for the 12C+209Bi and 14N+Pb reactions with a gold surface barrier silicon detector and mica nuclear track detectors.The measured fission excitation functions are found to be in good agreement with those calculated by the statistical evaporation model.The angular-momentum dependent fission barrier is also discussed.
From some special phenomena observed in the reaction of 16O+27Al,we proposed a simple model of INDIC.in which a direct projectile breakup in the initial stage (16O→12C+α)is succeeded by a dissipative interaction between the heavy projectile fragment (HPF) 12C and the target nucleus 27Al in the final state.An analysis and cpmparis on with the experimental data for 16O+27Al reaction was performed.
In this paper,a recurrent formula for α-row partition is given.The multiplicity of total angular momentum of single-j fermion system and single-l boson system have been calculated with this formula.This formula is vary efficient to simplify the calculation of fractional parentage coefficients.
Some analytical expressions of state expansion coefficents for SON SON－1 in terms of SUN SUN－1 SON－1 are derived.Analytical expressions of some multiplicity-free isoscalar factors for SUN SON for the coupling [w1w20…0]×[w30…0]→[w1w20…0] for the SUN group are obtained by using these coefficients and isoscalar factors for SON SON－1.
Many superdeformed bands have been observed in A=120—140 mass region.The occupation of vi13/2 orbit is generally considered as the important cause.vi13/2 band head energy and deformation of odd N nuclei for Z=56—64 and N=69—77 has been calculated systematically with our modified Nilsson κ,μ parameters in this mass region.Results show that on the one hand,the occupation of vi13/2 orbit does favor the superdeformation tendency of nuclei; and on the other hand,the possible candidates of low lying vi13/2 configuration for experimental observation.
The condensation of the naive fermions in an arbitrary dimensional lattice is given in the tree graph approximation.No chiral symmetry spontaneous broken is found.
We have analyzed and studied the time variation of the daily counting rates of the very high-energy events observed by a large cloud-chamber system during August 1972 at a mountain altitude of 3200 meters above sea-level.An obvious increase of counting rates occurred during the 4th and 7th,August,1972 solar cosmic ray flares is found.These daily counting rates are higher than 3σ of the daily counting rate averaged from 10th to 26th,August.The average energy of the events corresponds to a primary cosmic-ray energy of 1013eV.
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