1994 Vol. 18, No. 3
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The low spin level structure of 187Au has been studied. by isotopically separated method. The reaction was 177HF(19F,9n)187T1 with beam energy 175MeV. The level scheme of 187Au was expanded and enhanced through analyzing γ-γ and γ-e coincidence data. The collective band structures and the coupling single proton with different even-eved cores were discussed.
The velocities and allgles of fission partners emitted from reactions in 12C+159Tb/197Au/209Bi systems with bombarding energy of E/A=46.7MeV are measured. The linear momentum transfer from projectile to target. mass and out-of-reaction plane angle distributions of fission fragments are studied, and the temperatures of the target residues are extracted. These results have been explained by statistical binary decay model. It seems that the compound-like system with high temperature about 4-5MeV has been formed through incomplete fusion with incident energy up to 50MeV/A and it decays by fission and light particle emission.
Based on the picture of two－source emission, the multiplicity and pseudorapidity distribution of shower particles are described in high energy lepton－nucleus collisions. The calculated results are in agreement with the experimental data of neutrinoemulsion collisions in the energy range from 3 up to 210 GeV.
By using super-Poincare tensor calculus, we construct an N = 1 supergravity theory in 3-dimensions, and the most general Lagrangian is obtained. The mechanism of spontaneous supersymmetry breaking and super Higgs effect are studied in detail.
Using the variational method, we calculate the vector meson mass Mv in the Lattice Schwinger model with massive Wilson fermions, and then calculate the rate of change of the vector meson mass M. with the fermion mass m(at m=0). Our results are consistent with the exact value in the continuum.
In the framework of thermal field dynamics, the reaction process in QGP is investigated. It is found that the statistical effect of the internal lines cannot be neglected. The contribution of thermal vacuum polarization to the dilepton production rate is also calculated.
The relation between the second order factorial moment and the number of participant nucleons in high energy induced nuclear reactions is deduced by taking account of the nuclear collision geometry. It is shown that in projectile fragmentation region of the high energy collisions the intermittent property of the final-state particles in hadron-nucleus reactions is dependent on the intermittent character of the sub-process of hadron-hadron collisions, but in target fragmentation region it mainly depends on the fluctuation of the number of participant nucleons. For nucleus-nucleus reactions (B << A), its intermittent strength is lower than that of hadron-nucleus reactions.
Using the particle-number conserving(PNC) method for treating the cranked shell model, the bandhead moments of inertia of the superdeformed(SD) bands 192Hg and 194Hg(1,2,3) were calculated. The configuration structures of the SD bands near the bandheads and the mechanism for the variation of bandhead moments of inertia with the pairing interaction strength G were investigated. The analyses show: (1) The difference in the bandhead moments of inertia, δJ0, is sensitive to the pairing interaction strength, but insensitive to the Nilsson parameters K,μ and the deformation. (2)In A～190 region the pairing interaction still plays an important role and the δJ0 is mainly attributed to the blocking effect. (3) The pairing interaction strength in SD nuclei seems much weaker than in normally deformed nuclei.
The exact treatment for the cranked single-j shell model Hamiltonian using the particle-number conserving method and the systematic analysis for the .pair transfer matrix element in rotating nuclei have been done. In contrast to the previous conclusion drawn from the usual Hatree-Fock-Bogoliubov(HFB) method or the number projected HFB treatment, for the pair transfer matrix element from the yrast band to yrast band, a smooth and slow variation with co is observed and no oscillation behavior occurs. But diabolic pair transfer is expected to occur in some higher excited bands.
The deexcitation spins of the superdeformed bands in the mass～150 region are determined by using multiple V-shaped plot. The agreement between the calculated and observed transition energies, the kinematic and dynamic moments of inertia is quite well when a correct spin assignment is made.
The covariant form of the Langevin equation and the Fokker-Planck equation describing the nuclear fission process is studied. The transformations of dynamical parameters are given.
The branching rules for group chain U(N)SP(N)O(3) of the irreducible representations [2a1b] of U(N) are discussed in some detail. Simple analytical recurrent formulae of these branching rules for above group chain are obtained. They are very efficient to simplify the calculations of Fractional Parentage Coefficients. This method can be used to find the branching rules for the group cLam U(N)O(N)O(3) too.
We propose a new baryon wave function which is constructed from the three quark configuration with SU(6) symmetry together with the configuration of the accompanying excitation of sea quark and valence quark. Using this wave function, the calculated results of GA/GV, μp/μn. and the contribution of quark spin to the proton spin are in fair agreement with the experimental data.
In this paper using constituent-quark model of nucleon we have calculated nucleon structure functions of Oxygen nucleus and Uranium nucleus, and with which we have analysed O+U→μμ+X Drell-Yan processes. The evaluated cross sections are in good agreement with recent data of the NA38 Group. We have shown the total influence of all nuclear effects acting on these cross sections could change its magnitude even about 15%, thus the nuclear effects should not be neglected when discussing problems such as searching quark gluon plasma in the suppression phenomenon of J/ψ yields. Further more, phenomenological analysis shows that the K factor which characterizes contribution of perturbative QCD in this process decreases slowly as the lepton pair mass m increases, which is consistent with asymptotic freedom of QCD and agrees with previous results on this problem.
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