1994 Vol. 18, No. S4
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A parton model based on perturbative QCD is developed for the description of ultrahigh energy interaction between cosmic ray and air nuclei. A LLA QCD calculation of jet production cross section in proton-proton scattering and a hadronization scheme based on independent fragmentation model are presented. A number of parameters in the hadronization scheme are selected such that the basic features of hadronic production in e+e- collision covering C.M. energy region from 14 GeV to 91 GeV can be reproduced. A Monte Carlo generator is constructed to reproduce the basic characteristics of proton-antiproton scattering at the C.M. energy from 80 GeV to 1800 GeV and extended to ultrahigh energy region up to 22 TeV.
Adopting a nuclear collision geometry and a two-component model of hadron-hadron interaction, a Monte Carlo generator on p-N and p-A interactions has been established. Using this generator, the inelasticity distribution, average inelasticity of p-A interaction and their dependence on the mass of target have been studied.
A new rotational band was identified in the reaction of 28Si+92Mo by means of in-beam 7-ray methods. By carefully analyzing the band intensity and structure properties, the band is considered likely as the h11/2 proton band of 117Cs.
The Poisson-Lie structure of non-linear σ-model is given in 0(n)/0(n-1) symmetric space,and the covariant relation between moving frame and fixed frame is discussed by making use of the method of covariant decomposition. It is clear that the field-dependence of the r and s matrices results from the connection of Sn-1 manifold.
We propose a new quantization scheme with which and by the equation of motion the quantization problem of both independent and dependent interacting fields in QED can be solved simultaneously. When the external gauge field Aμex)≠0 (i.e., the Fermion field ψ/(x) and the electromagnetic field Aμ(x) are independent of each other) our scheme gives the same result as the usual quantization approach. When the external gauge field is absent the usual quantization conditions fail since it is not compatible with equation of motion, meanwhile our scheme is still valid. These results are demonstrated with solvable QED in 1+1 dimension.
The effective potential of the standard model with neutral current is calculated consistently to (λ3/2, g3, g'3) order at high temperature by the resummation of the hard thermal loops in the tadpole diagrams. The difficulties in the naive calculation are overcome. It is proved that the electroweak transition is of the first order and the critical temperature is obtained.
A method of solving the transport equations for quark-gluon plasma beyond the Abelian dominance approximation is given. The transport coefficients of colored quark-antiquark plasma are calculated using this method. The effects of non-Abelian color field on them are discussed.
Based on the two geometrical pictures, namely the independent N-N collision and participant-picture, the new data of transverse energy distributions in high energy p-A collisions recently published by HELIOS are analyzed. The influence of the choices of various model parameters is discussed, and the results are compared to those in A-A collisions.
A new relativistic method for calculation of particle-hole and Delta-hole excitations of the pion in nuclear matter is proposed. The difference between the usual method and ours is pointed out. The dispersion relation of the pion meson including virtual particle-hole excitations is analyzed. The results are compared numerically with that for the non-relativistic counterpart. The formulas of relativistic Delta-hole excitation induced by pion in nuclear matter are also discussed.
Starting from shell model configuration and effective nucleon-nucleon interaction, we propose a microscopic approach to study the properties of high-spin states of even-even nuclei in terms of the generalized boson expansion theory.
With the effective interactions consisting of a pairing force, a quadrupole pairing force and a quadrupole-quadrupole force among yalence nucleons, the microscopic approach based on the generalized Dyson expansion theory is applied in studying both the low-lying and high spin states for the isotones 154Dy, 156Er and 158Yb. In the truncated state space, the configurations (sd)N and (sd)N-1 + neutron-pair are assumed, respectively, for the low-lying and high spin states, although the same values of strength parameters are taken in the numerical calculations in the two subspaces. The calculated results are in a good agreement with experiment. In particular, the data of first backbendings are reproduced satisfactorily.
The position of saddle point and potential energy surface near the saddle point are studied for a given fissioning system. Multidimensional inertia and viscosity tensors are calculated with both irrotational flow and Werner-Wheeler approximation, and the fission rate is calculated with multidimensional Kxamers formula. It is found that the fission rate increases reasonably with the number of dimensions considered and changes only slightly with the assumptions used in kinetic energy calculations. The results of calculations indicate that a suitable three-dimensional calculation will be sufficient to yield accurate fission rates.
The data of a-particle-induced reactions on 10,11B at 31.2 MeV have been analyzed by using the program MARS-SATURN EFR-DWBA. The results show that direct stripping reactions are the main reaction mechanism in 10,11B(α, x)*C. However, there are direct stripping plus heavy particle stripping in the reactions 11B(α, d0)13C and 11B(α, p0)14C. In addition, the mechanism of compound nucleus seem to be taken into account for the peak of intermediate angular region in the reaction 11B(α, p0)14C. Finally, the agreement between theoretical calculation and experimental data is more satisfactory in those reactions:10B(α, p0)13C,10B(α, d1)12C* and 11B(α, d0)13C.
The low-lying states and electromagnetic transitions of 208Tl are calculated within the framework of a shell model. The theoretical results are in good agreement with the experimental data. It shows that MSDI may be used to accurately describe the properties of 208Tl. The logft1/2 values of 208Hg are estimated.
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