1987 Vol. 11, No. 2
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The experimental data processing method of measuring the mean-free-path of nuclear interactions is discussed. Estimator formulas in several experimental conditions are obtained by using the maximum likelihood method. The result of Mente-Carlo simulation shows that in case of the experimental data with poor statistics the maximum likelihood extimate value is more accurate than the least squares fitting value geuerally used.
This article described the Self-Quenching-Streamer properties of mixed gases such as: Ar+CH4(1:1) bubbled through Methylal at 0℃, Ar+CO2(1:2) bubbled through n-Pentane and Ar+Isobutane. We also measured the relation of streamer signal amplitute with the projection length at the direction of anode wire, and the drift time.
The experiments were performed using a 20×10×330mm3 brass tube with a 50μm diameter stainless steel wire made in China. We also calculated the energy resolution of the calorimeter worked in SQS mode with Monte-Carlo method.
We have discussed the stochastic quantization with the spin 3/2 field with the proper kernel function F(x, y). The covariant propagator is obtained, the interaction with the electromagnetic field is also considered.
In the present work, the m⊥ mean scaling expression is obtained from the transverse momentum distribution of the secondary particles in e+e－ annihilation the case of m⊥>>T.
We discuss cylindrical Einstein-equation via the G-gauge covariant formulation, the basic equations are related to the first and the second fundamental differential forms on the soliton surfaces in the symmetric space. By means of the dual symmetry of the system, the linear scattering equations, Bäcklund transformations and Ricati-equations are established, whose integrabilities are shown. The geometric meanings of Bäcklund transformations and Riccati-equations are obtained.
In this paper we have discussed the ratios between the cross sections of muon-production of J/ψ particles with models explaining the EMC effect in order to investigate the distribution function of gluon in bound nucleon. Comparing the calculated results with the relevant experimental data of EMC group in the small x region, we show that none of these models can explain the ratio satisfactorily. We have analysized the plausible reason s and furnished it with our conjectures.
In this paper the plasma effects of gauge theories are investigated. The results for the QED case obtained in a previous paper are extended to the QCD case. The calculation shows that the effects are identical for hoth QED and QCD cases. In one op approximation.
In this paper, a SU(2)×SU(2) chiral model on 2-dimensional random lattice is studied by Monte Carlo simulation with 8×8, 9×9 and 10×10 lattice volumes. The results of its energy and specific heat per link are obtained and coincide with that of SU(2) gauge system on 4-dimension. The systems enter crossover region at β1.0 but show no obvious evidences of continuous phase transition. Thus we believed that the correspondences between 4-dimensional SU(N) gauge theory and 2-dimensional SU(N)×SU(N) spin system may be generized to interesting random lattice.
Recently an important feature has been revealed in experiment by SppS: the ratio of baxyon to meson in final particles remarkably with the increases of energy, which can not be explained by the current theories. By combination of the "three fireball model" of the nondiffractive hadron-hadron collision and the "quark combination" we proposed caller, this can be explained naturally. and further, some predictions for high energy range are made.
We discuss bound states of a boson in the field of Kerr-Newman's naked singularity by the spectrum Analysis of the self-conjugate extension of linear differential operators. The results show that the self-conjugate extension of the Hamiltonian of the boson has only discrete spectrum in the interval (—μ,μ). From which we can infer that there are no boson bound states if μ=0. Boson bound states appear when μ≠0.
The heavy quarkonium spectra were discussed with a confinement potential of the form Vc(r)=1/2kr2+λr4 by using the Hypervirial Pade Approach. With choice of suitable parameters, we calculated the binding energy levels of cc and bb systems which provide good agreement with the experimental values.
The observables in the proton-nucleus elastic scattering are described by using the Dirac equation with relativistic optical potential. The treatment of Dirac equation with Lorentz scalar and Lorentz vector potential is discussed. The equation is solved by exact partial wave method. The calculated results of 500MeV proton—208Pb,40Ca, and 4He scatterings are presented and compared with experimental data. It is shown that the calculation of defferential cross section, analyzing power and spin rotation functions are in good agreement with experimental data.
We examine how the density matrix affects the Pauli corrections to the pion-nucleus optical potential in the region of the Δ33 resonance,i.e. for pion kinetic energies of 50～300MeV. Four different approaches-shell Model with harmonic oscillator wave functions, uniform, local and revised local Fermi-Gas models-are used to calculate the density matrix.
The effective interaction between Λ and α is obtained by folding the Λ-N interaction to the nucleon density of the α particle, which gives the correct form factor of α particle in the high energy electron scattering experiment. Using this effective interaction, we calculate the binding energy of the doudle Λ in 6ΛΛHe and the binding energy of Λ in 9ΛΛBe by means of the adiabatic approximation to the hyperspherical harmonic method. The results are satisfactory.
We analyse the multiplicity distributions of negative particles produced in p-Ar and p-Xe collisions at 200GeV/c by a multiple collision model. The energy loss suffered by the incident baryons in its passage through the nucleus is explicitly included in the calculation. The agreement is satisfactory.
The dependence of the measuring accuracy of the rotating coil magnetometer on its misa-lignments is studied in this paper. The expressions of magnetic field measurement error due to the misalignments of the magnetometer are given also.
The article describes a small-size are discharge ion source. Some of its basic parameters are measured by combining the are discharge with the electron oscillation. The ion current is 7mA. It can produce multi-charge ions. The extraction structure is commonly used by this source and the r.f. ion source. This ion source has been used in a 400keV ion implanter in Beijing Normal University and it is stable in operation.
Quasi elastic and deep inelastic collision induced by 16O+27Al at the bombarding energies below 5.3MeV/A have been studied in detail. Experimental angular, energy, atomic charge distribution and contour plots of the differential cross sections d3σ/dEdΩdZ on E-θ plan are presented, their evolution with the bombarding energies are analysed. The competion between quaslelastic and deep inelastic collision as a function of the bombarding energies has been discussed.
The projectile-like fragments produced by 93MeV 14N on natCa have been measured with a large area position sensitive ionization chamber. Energy spectra, angular distributions and contour plots of d3σ/dΩdEdZ on TKE-θ plane for various elements from Li to Mg have been obtained. The variances of the charge distributions σ2 as a function of the dissipated energy have been deduced too. In the framework of a simple diffusion model the experimental results have been analysed and discussed.
The intermediate structure phenoment are explained in 12C+12C reaction system by means of the rotation-vibration model for nuclear molecular.
Within the coupled-pair model space constructed through S, D, G and I "pair", which are defined in f-p shell by means of the folded-diagram perturbation theory, the spectra of the states of 44Ca are calculated. The results show that for the nucleus having four identical valence-nucleons outside the core 40Ca this truncated model space can reproduce the experimental low-lying spectra of 44Ca quite well.
In this paper, some rotational spectra are discussed through the F-spin breaking, which can well reproduce odd K bands in some nuclei. These bands may be the manifestation of the degree of freedom of F-spin.
The relation between α-backbending, nucleon-nucleon correlation and deformation in nuclei has been discussed. In general the backbending phenomena in gauge space are related to shape transition, however α-backbending is not only related to the quadrupole shape transition, but also related to other kinds of shape transition. The α-backbending phenomena also depend on the competition between n-p correlation and pair correlation, i.e., n-n and p-p correlation. The change of nuclear deformation with increasing nucleon number can be fundamentally described by unified shell model.
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