1985 Vol. 9, No. 1
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The measurements of the electron drift velocity as a function of the electric field have been made in a small drift chamber with uniform electric field for Ar/CH4, Ar/i-C4H10, Ar/CO2 and SQS gas mixtures. The values of the electric field range from obout 0.3 to 2.5kV/cm. The results of the measurements are discussed.
The function, the structure and the cosmic ray test of the outer drift chamber for PEP-4 Experiment at SLAC are described.
A cheap real-time picture memory used for matching TV camera and TV monitor is described. The structure is very simple. It is able to do real-time accessing of video pictures and 256×256 picture elements with 4 bits of gray levels are used. The width of picture element is within 180ns.
In this paper both the normal product form and the coherent state form of the Wigner operator are derived. Furthermore, the applications of the new forms of the Wigner operator are also presented, which are involved in deriving some new quantum operator formulas, in the coherent state generalization of the Moyal theorem, and in evaluating some quantum operators which corresponds to the given classical functions in the Weyl manner and vice versa.
The feature of Manton's lattice action in the SU(5) four-dimensional lattice gauge theory is investigated by means of Monte Carlo simulation. A rather smooth curve of the internal energy is obtained, no discontinuity in the average action perplaquette is found in opposition to the resultes of usually adopted Wilson's action. An evidence of a higher order phase transition with Manton's action is also found.
The triangle lattice Eguchi-Kawai model is studied by using the Monte Carlo technique. The results indicate that in the two-dimensional case U(1) symmetry is not broken but in the three-dimensional case a clear evidence of spontaneous breaking of the U(1) symmetry is observed in the weak coupling region.
The differential cross sections of the elastic scattering of K±on 40—48Ca are calculated in the framework of eikonal approximation. The theoretical values obtained by using different parameters are compared. Through adjusting the parameters of the neutron distribution, the improvement of the coincidence between the theoretical values and the experimental data is arrived. The result shows that the r.m.s radius of the neutron distribution of 40Ca is smaller than that of the proton. (about 0.15fm smaller) and the surface thickness of the neutron distribution of 40Ca is thinner than that of proton. This is consistent with the results of computation made by H.F. method and agrees with the analysis of elastic scaatering of protons in the mediate energy on 40Ca by other authors.
An energy-independent nucleon-nucleon potential from meson exchanges is derived and the tensor force in this potential is investigated.
In the frame of the first order approach of KMT multiple scattering theory, using the eikonal distored wave impulse approximation, together with the empirical transition densities, the inelastic scattering of the pion mesons on 40Ca is investigated, and the inelastic scattering of the kaon mesons on 40Ca is also predicted.
The energy spectra and angular distributions of the emitted α particles in the reactions of the 69.5MeV 12C bombarding 12C,27Al and natCa have been measured and analysed using the fast particle exciton model. The contribution from the equilibrium and preequilibrium α-emissions is calculated to be 89%, 81% and 83% of the total α yields for the three reactions respectively, where the preequilibrium α emissions are 11%, 14% and 16% respectively. A small contribution comes from the other reaction mechanism.
The expansions of the excitation energy of the ground band in even-even deformed nucleus are discussed in the framework of our expression deduced in the previous papers. The conventional I(I+1)-expansion which is applicable to the region of low angular momenta is obtained and its radius of convergence is estimated. It can be proved that the ω1-expansion is always convergent and hence the empirical fact that the ωI-expansion converges better than the I(I+1)-expansion is explained satisfactorily.
The summed energy spectra and the angular correlation for two alpha particles from the 12C(α, 2α) 8Be reaction were measured.
The data show that the quasi-free scattering of incident alpha particle from the alpha cluster in 12C is probably the main mechanism of the reaction on 12C. The data are analyzed by means of PWIA. The probability of forming cluster is 0.07 which is close to the result obtained by James at high incident energy.
Starting from the state density formula which accounts for proton-neutron distinguish ability, a modification for complexparticle emission probability in the preequilibrium exciton model is given, which modified the complex-particle emission probability Wαβ and the pure combination probability Rαβ given by C.K.Cline and I.Ribansky et al. The calculated results by using modification formula are in better agreement with the experimental data compared to that of Cline and Ribansky.
The mechanism of transfering a cluster of nucleons between two colliding nuclei is considered to explain the backward angle oscillatory rise in the differential cross section of the elastic scattering between certain nuclei, such as 16O+24Mg or 20Ne+24Mg. The nuclear molecular orbit approximation theory is applied. For one-step transfer, if the parameter involved is assumed to be adjustable, the numerical calculations can be made to fit the experimental results naturally.
A convenient method is introduced to calculate the rate of escape of Brownian particle over potential barriers by exact solution of Smoluchowskian equation. This method is applied to calculate the nuclear fission probabilities. The results for four different cases are compared with the results of other theories.
The general equation of transverse motion is discussed and its solution is presented. It indicates that in the currently used equation of motion the focusing effect of the magnetic field is overestimated when the initial moment is not zero.
The variational analysis of the phase structure of the SU(3) lattice gauge theory with a mixed fundamental-adjoint action is presented. All transitions are found to be the first order. The shape of the first order transition line is roughly consistent with the one given by Monte Carlo method.
The scattering amplitude of geometrical model is extented into a complex form. It is used to calculate the pp elastic scattering for √s=540GeV. It can fit the shape of the differential cross section and the dip position.
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