1998 Vol. 22, No. 6
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A new fitting method together with the Monte Carlo simulation is developed to process the full pulse-height spectrum of a 137Cs source in PbWO4 crystals to get the precise light yield of the crystal in photoelectrons per MeV. This method is also useful for other kinds of crystal measurements.
In this paper, the source and time distribution of background in the single photon time measurement are studied. By using the method of coincident gate the random coincident background and the Cherenkov light produced on the window of the photocathode of photomultiplier are suppressed effectively.
The lattice U(1) and U(1) -Higgs models with Symanzik action are analytically studied at finite temperature using variational cumulant expansion (VCE). The Polyakov lines
We consider the contributions of new gauge bosons to Wtb cuopling in one generation technicolor (OGTC) model and topcolor assisted multiscale technicolor (TOPCMTC) model. We find that the exchange of diagonal extended technicolor (ETC) gauge boson has no contribution to Wtb coupling. Using the LEP value of Rb, we calculate the corrections to the CKM matrix element Vtb which arise from the sideways ETC gauge boson in OGTC model and the sideways ETC gauge bosons and colorn exchange in TOPCMTC model. We find that the δVtb is signficantly large for a certain set of the parameters of either OGTC model or TOPCMTC model which might be detected in the Fermilab Tevatron Run 3 experiments.
In Affine Toda field theory, links among three generating functions for integrals of motion derived from P. (Ⅰ) are studied, and some classically integrable boundary conditions are obtained. An infinite number of integrals of motion are calculated in ZMS model with quasi-periodic condition. We find the classically integrable boundary conditions and K± matrices of ZMS model with independent boundary conditions on each end. It is identified that an infinite number of integrals of motion does exist and one of them is the Hamiltonian, so this system is completely integrable.
Using the self-affine fractal of two-dimensional phase space and Monte Carlo simulation, the dependence of the factorial moments and the factorial correlations on the multiplicity relative strength of fluctuation are studied for non-fixing multiplicity. It is discovered that the factorial moments and the factorial correlations depend on the muldplicity relative strength of fluctuation nf, but the intermittency does not depend on nf When nf is smaller, these dependence are dispelled.
Using the wavelet transformation, the probability distribution for the multiplicity phase space which is obtained by simulation from random cascading α model is discussed. We find that using the wavelet transformation the probability moments and the correlation moments for the experimental data of the multiplicity phase space probability distribution canbe directly analysed. An actual calculation mathod is suggested.
A finite range Gaussian 2-body interaction is applied in stead of the zero range 2-body part of the Skyrme interaction in the isospin-dependent quantum molecular dynamics model to simulate the transverse momentum in the reaction of system 93Nb(E=400MeV/u, b=3fm)+93Nb. The results show that the finite range nuclear force enhances the transverse momentum of the reaction system and it can partly replace the momentum-dependent part of the nucleon-nucleon interaction.
Using the particle-rotor model, a theoretical study of the superdeformed triaxial bands in 163Lu,165Lu and 167Lu is carried out. An overall and good agreement between the calculated and observed transition energies, kinematic and dynamic moments of inertia and transition quadrupole moments is obtained.
Based on an improved constituent quark model description, the Q2-evolution of the spin-dependent structure functions for proton and neutron are calculated in the resonance region. Moreover,the total photoabsorption cross sections are also predicted. The results are in agreement wiht the recent E143 data.
The energy spectra of heavy quark bound states are analyzed using the error-function-type potential and the one-gluon-exchange Coulomb-type force. The Debye screening mass at finite temperature and density is studied in the thermofield dynamics approach. The critical temperature and cridcal energy density for J/ψ dissociation in hot and dense matter are obtained.
The characteristics of the electron beam current transport in the electron gun of the electrocurtain accelerator were studied and the origin of the influence on longitudinal uniformity of beam current was analysed. The deflection of the cathode is considered under the boundary condition of perfect constraint.Then a newly designed electron gun is introduced with longitudinal uniformity of current within±10%.
In this paper, a new method that can diagnose the cell frequencies in a cavity without a perturbing probe is presented. The cell frequencies and couplings between cells arc estimated in terms of the measured passband performance. This method will simplify the tuning processes and make the tuning of a sealed cavity possible, It has been well checked with some numerical examples.
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