1986 Vol. 10, No. 2
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A model of pictorial drift chamber is constructed. The associated readout circuit of the model chamber is made with the capability of recording 8 hit events. The present study was undertaken to investigate the properties of the chamber, including spatial and double track resolutions, resolution of left/right ambiguity, as well as the pattern recognition of multi-track events. In this paper, the construction of the model chamber is briefly described. Also described are the principle and the block diagram of the readout circuit, the properties of each unit, as well as the properties of the whole circuit. The experimental results reported here include X-spatial resolution (σx=280μm), Z-spatial resolution(σz=3cm), and the reconstructed track picture of a cosmic ray shower.
The ground state energy of the positronium negative ion is calculated by using the variational method. The relativistic corrections (to the order of V2/C2) are calculated. The value of the correction E=4.5×10－4eV is obtained for the ground state energy.
The hadron 1→0 decay processes are discussed by using the Krapchev L0 approximation in a 3+1 dimensional theory. The coupling constant fπ, the electromagnetic decay width ΓV→l+l－, etc., are evaluated. Unlike what was done before, the phenomenological factor √Vbag is not introduced, however, the results obtained in this paper are in better agreement with the experimental data.
The variationalmethod in Lagrangian formalism is applied to investigate phase structure of the SU(2) lattice gauge theory with an action including six-link loops. Dimensionality dependence is also investigated.
We study manton's action and several other actions in lattice gauge theory with naive mean field approximation method and the method proposed by Shahbazyan. Values of β at crossover point are obtained with different kinds of SU(2) actions by using both mean field approximation method and the method proposed by Shahbazyan. While in later case, universality is assumed and the Monte Carlo results of SU(2) Wilson action and the relations between Wilson action and other actions are taken as input. The results of the two methods are compared and the universality assumption are checked.
In this paper we discuss the cohomology for translation group, analyze the property of each order of cocycles, claryfy some ambiguties, Meanwhile we introduce the generalized Mandelstam wave function which can realize the 3-cocycles of translation group.
Some general Chern-Simons cochains are easily obtained by expanding the Chern form according to the degree of the form in its submanifold and using the closed property of the Chern form. The recurrent relatuns of Chern form between submanifolds are discussed under some constraints. We also consider their application.
This paper deals with the models of grand unification of preon with confining weak interaction. Under the conditions of appropriate mass scales of unification and confinement, it is found that the hypercolor gauge group is SU(n) (n≤3) and satisfactory gauge groups of unification are SU(7), SU(8) and SO(14) by using the renormalization group method.
Using a potential model with relativistic correction we evaluated the spectrum, lepton decay widths and radiative transition widths of heavy quarkonium systems. In the model we assumed the vector confinement as well as the scallar confinement, but the ran ge of the former is shorter than the latter one. With this model the fine splitting of the heavy quarkonium spectrum is in satiofactory agreeinent with experimental data.
In the framework of Glauber's multiple scattering theory, the exact expressions of the amplitude for nucleus-nucleus inelastic scattering at high energy are derived. Taking inelastic scattering or 1.37GeV α on C12 as an example, the differential cross sections for 2+ and 3－ states of C12 have been calculated by thd rigid projectile approximation and exact method respectively. There some differences between the differntial cross sections obtained by these two methods. These two methods. These differences show the characters of these methods.
The principles and results to improve the BEPC storage ring lattice are described. The minimum β*x is chosen to be 0.08m so that the design luminosity reaches 2×1031cm－2﹒s－1. Increasing the ratio β*x/β*y, the required aperture of insertion quadrupoles as well as horizontal chromatic aberrations are reduced. A trunk with more variables of QFstrength is adopted to provide better dispersion suppression and smaller β function, modulation and the dynamical aperture of 12σx×12σy×12σE is attained. The phase advance between two major kickers is changed to be close to 180° in order to simplify the injection system. 4 straight sections where dispesion Dx is large are provided to place emittance control wigglers and other, 4 straight sections near to the zero disnersion regions will be useful for synchrotron radiation applications.
The radiation field around a high energy accelerator is a pulsed mixed radiation field of complex particle constituents. The distribution of the radiation field around a 10MeV proton Linac in commissioning is measured with a three detector system. The absorbed dose equivalent of both the neutrons and γ-rays in the Linac hall are measured. The average quality factor of the mixed-radiation field is given too. The results and uncertainty of the measurements are analyzed and disscussed.
For the nuclear deformation of λ=2,4,6…, the most important symmetries are axial symmetry and R(π) invariance , but probably there is R(π/2) invariance in some nuclei. In this paper the possible occurrence of this new symmetry is analysed in general. In particular, the condition for the existence of the R(π/2) invariance, wave function of nucleus with R(π/2) invariance and signature-dependent terms in the matrix elements of an operator F are discussed in detail.
These provide an analysis of the experimental data, for example the alternating behavior of level energies and B(E/2) for Kπ=0+ and Kπ=0－ bands.
The modification of the radial shape of the real part of the microscopic optical potential by the imaginary part of the off-shell single-particle potential from secondorder diagram contributions is discussed by using the Skyrme interaction SKa, and by means of the dispersion relation and local density approximation. As an example, the modified values for 40Ca at E—EF≤50MeV are calculated. The calculated results lead to slightly deeper real part of the optical potential. The modification is larger near the neuclear surface at lower energies, and is larger in the nuclear center region at higher energies.
The phase transition from the super fluid to normal state with the increase of the seniority number in the two-level pairing force model is studied with a boson-fermion composite representation. Criteria for identifying the phase transition with observable phase characteristics are discussed.
Eighteen muon shower events of large zenith angles from Mt. Ganbala emulsion chambers were selected and analysed. The intensity and the integral energy spectrum of muon showers at energies higher than 3TeV are given.
We discuss the symmetry of a dyons system, and show that the Hamiltonian of dyons HD=1/2M π2－α/r+μ2/2Mr2 has SO(4)symmetry.
The Triangle latticequenched Eguchi-Kawai model is studied by using the Monte Carlo technique. The results indicate that in the three-dimensional case the behavior in the weak coupling region could be improved and closes to the results of the standard model.
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