1993 Vol. 17, No. 7
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The enriched neon was bombarded by 35.5MeV protons from linear accelerator at Institute of High Energy Physics.The spctra of beta delayed alpha decay of 20Na were obtained.A new peak at 0.78MeV was observed in the spectra.From the particle identification,particle spectra and the life time measurement it was believed that the peak at 0.78MeV was from low energy alpha decay channel first observed in the beta delayed alpha decay of 20Na.
The localization properties of multiwire chamber was studied experimentally in the Self-Quenching Streamer mode.The distribution of induced charge at neighboring wires and cathodes was measured in two chambers with different structure at different high voltages.Through the measurement of the ratio of induced charge on the two neighboring wires and the center of gravities of cathode induced charge,we gor the position accuracies σx≤350μm and σz≤250μm.
Based on the assumption that galactic cosmic ray(GCR) is produced by the diffusive shock wave acceleration of supernova explosion in the Galaxy,we simulate the propagation of GCR nuclei in the interstellar medium by using the Monte Carlo method.In our simulating calculation,we use the nuclear interaction cross sections and the probabilities of nuclear fragmentation measured in the accelerator experiments;we consider the ionization energy loss of GCR nuclei in the standard leaky box model and the effect of solar modulation on the GCR nuclei by using force-field approximation.Our calculating B/C,V/Fe and the spectra of O and Fe can be compared with experimental data.Finally,we discuss the effects of different compress ratios of shock wave on the calculation results.
This paper describes the design and initial operation of the Zhengzhou Air Shower Array.The array is composed of 8 scintillation counters and its detection area is about 30m×30m.An international standard CAMAC system is employed to control the experiment.The measurement of cosmic ray showers with size range from 4×104 to 8×106 is performed continuously and automatically.
In this paper the structure of the wide resonance θ(1720) produced in J/ψ hadronic decays is studied by using the generalized moment analysis.Since the production ratio of the f'2(1525) is very small in the process J/ψ→ωθ(1720) we may neglect the influence of the f'2(1525).Whereas the production ratio of the f'2(1525) is larger in the process J/ψ→φθ(1720),we must consider the coherence effects of the f'2(1525).From the studies of the two processes and the corresponding J/ψ radiative decay we are able to understand the structure of the wide resonance θ(1720) better.
In this paper,the general non-Abelian wormholes are obtained in 3D and 4D manifold by adding the contribution of a cosmological constant and a Kalb-Ramond field in baby universe's action.
A possible form of ρ0-ω mixing is proposed.The mixing coupling constant is determined by (ρ0,ω)→π+π－ decay rates.The (ρ0,ω) positron-electron pair decay rates are calculated and it is found that the mixing effect contributes 9.4% enhancement to ρ0→e+e－ and 2.6% raduction to ω→e+e－ decay processes.
The Vector-Boson distribution functions inside electron or quark are obtained in the case of polarization.The formula and the numerical results of the distributions for the application of unpolarized and polarized process are discussed.The distribution asymmetry and the luminosity factors are introduced.
We extend the self-dual field theory with a linear self-dual constraint to include an arbitrary potential of the Lagrange multiplier field.We show that this theory coincides with the Floreanini-Jackiw's formalism only for a quadratic potential,and the free scalar field theory for the potentials of the Lagrange multiplier to finite and positive power.
q-oscillator representations of the quantum superalgebra splq(2,1) are given in terms of one q-boson and one q-fermion or with two q-bosons and two q-fermions.
The superdeformed (SD) rotational bands in Hg and Pb are analyzed by means of the abc expression for fotational bands:E(I)=a[1+cL(I+1)][1+bI(I+1)－1],which was derived from the Bohr Hamiltonian.The agreement between calculated and observed transition energies is incredibly well.The deviation of the calculated E's from the observed results turns out to be │δ│≤0.5keV (except for a few cases,0.5keV│δ│≤0.75keV).Some transitions which have not been observed yet in these SD bands are also predicted,which may be useful for experimental investigation.
In the case of central collisions,the mechanism of fragmentation is studied within the framework of Boltzmann-Uehling-Uhlenbeck theory from 10MeV/u to 100MeV/u for 20Ne+20Ne collision system.The exciting energy and the problem about whether completed thermolization be attained have also been discussed.
In this paper,the confinement potential with colour screening effect as well as the mixing of configuration space,the basis functions with different size parameter b and the vector coupling component of confining potential have been considered to study the N、Δ spectra.The results show that these effects can improve theoretical calculations and give a more reasonable and better description for N、Δ systems.
Peripheral collisions for 20Ne+20Ne system at 25MeV/A were analysed in detail by QMD method.Its characteristics,as well as the coexistence and competition of deep inelastic collision and fragmentation were discussed.The sources of intermediate mass fragments were also explored.
The deep optical potential and the parity-dependent effect between heavy-ions have been discussed by analysing the resonant band of a quasi-molecular state for the 16O+20Ne system within the frameworks of the nuclear molecular theory and the extended optical model.The gross resonant structures appeared in the excitation functions and the backward-angle oscillatory structures observed in the angular distribution have been reproduced successfully.
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