1983 Vol. 7, No. 4
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The absolute vertical intensity and momentum spectrum of cosmic-ray muons at sea level of Beijing district has measured with a range spectrometer composed by a counter telescope system of four large area scintillation counters (two plastic and two liquid scintillators) and a pile of Pb absorber. In addition, a 70×50×30cm3 streamer chamber was used as a track detector for shower rejection. The integral spectrum of the momentum was measured from 0.2GeV/c to 1.3 GeV/c. The integral flux at 0.3 GeV/c is 9.2××10－3sr－1cm－2s－1. The ratio of shower rejection is about 30% obtained by scanning streamer tracks from 1.6×104 photographs.
A method to solving a few practical problems in analysing lifetime spectrum is searched through analysis of the lifetime specrtra of e+ annihilation in amorphous alloy samples and other ones. It includes the selection of the starting point of fitting data one by one above a certain time range on the right of the spectrum peak, the normolazation of the sum of relative intensities of the lifetime components by adjusting the zero time position, and finally testing the tail component to diminish the effect on analysis of the end position of the fitting data.
In this article, emission and absorption are considered to be of equally important constituents in the physics mechanism of the anomalous Cerenkov radiation. The possibility and the characteristic of such radiations caused by electron-beam passing through sodiun vapor are studied theoretically. The effects of the of the incident beam energy, the sodium vapor pressure, the medium thickness passed through by the emitting photons and other factors on the radiant flow-intensity, the angular distribution and the red-shift of the spectrum are calculated.
Using the relation of time of four outputs in the scintillation hodoscope (50cm×50cm×0.5cm), the position of incident particles is determined.
The time resolution σt=140—360 ps(correspondingly the position resolution σL=2—5 cm) has been obtained.
Based on the Curtright-Zachos's formulation of O(N) Super-chiral model we derive a set of infinitely conserved currents via Noether analysis by introducing an extended local transformation. We show that there appears Kac-Moody-type algebraic structure for the variation 2-dimensional spinor ψ in the theory.
The proton and meson are regarded as bound state which are composed of quarks. The pionic two-body decay amplitude of the proton in the SU(5) grand unification gauge theory is computed by using field theory method. This amplitude is contained an overlap integral of the space wave functions between the proton and pion, with the naive quark-parton idea, to the lowest approximation, this overlap integral is ∫d4u1ψπ*(0, u1)ψP(u1, 0, 0). By using the wavefunction of ground state for the relativistic harmonicoscillator potential, we have computed the partial decay rate of the process p→π0e+. The result is (2.1×1029 years) and (4.4×1031 years) for mx=1014GeV and mx=1014GeV, respectively.
Utilizing the Clebsch-Gordan coefficients of the permutation groups, the SU(mn)SU(m)×SU(n) single-particle coefficients of fractional parentage for up to five particles are calculated and tabulated for arbitrary m and n.
In this paper, we study the N-N and N-Δ spin orbit forces in the quark model. The results are: (1) the N-N spin orbit force is attractive for the triplet odd state, this feature is qualitatively agreement with the phenomenological potential which is determined by the N-N scattering data. (2) the direct term of the Δ-N spin orbit force is attractive mainly and the exchange term of that is attractive for the case of ST=12 and 21, repulsive for the case of ST=11 and 22. All of these results will be helpful to understand the property of the N-Δ spin-orbit force.
The theoricians1) have found that the virtual excitation of GR plays an important role in 87Sr(n, n')87mSr inelastic scattering, the target with a hole in a neutron close shell, even when the incident neutron energy is around 3 MeV. The cross section of 87Sr(n, n')87mSr (9+/2 1－/2) is calculated, for compound nucleus' with H-F formula, for GR'S with phenomenological as well as microscopical method, but there are no experimental data could compare with them directly yet.
We measure the total inelastic cross section with activation method for En<2 MeV, which lead to those levels that decay through the first exdited state (1/2－), i.e. the metastable state with a half live of 2.83 hours. Together with the data given by J. K. Temperley et al 5), we present the total eycitation curve.
The quasi-Δ33 doorway state model, previously developed to describe pion-nucleus scattering , is applied to the study of coherent π0 photoproduction on nuclei. The unifying feature of this approach for pion elastic scattering and photoproduction are briefly discussed. We compare our sesults with W. Weise's isobar-hole model calculations and plane wave impulse approximation calculations. The results are presented for 16O(γ, π0)16O and 12C(γ, π0)12C, and compared to the available experimental data. It has a large suppression for the cross section compared with the impule approximation prediction.
In this paper a set of energy-independent local Woods-Saxon potential parameters for 40Ca are adjusted to perform the single-particle shell model calculations. By use of these parameters the single-particle energies are calculated. The results are compared with the experimental data. It is shown that the agreements between them are not only in order but also in position of levels which are very close except the theoretical values for 1s state of neutrons 1s and 1p states of protons are evidently lower than the experimental ones. In addition, the charge density and the root mean square radius of charge distribution are also calculated. They are in very good agreement with experimental values obtained from the elastic electron scattering and the muonic X-ray data. On the basis of the previous studies the nucleon densities. kinetic energy densities and spin densities of 40Ca are calculated. Their shape and values are presented in this paper.
The exact amplitudes of the Glauber theory for the nucleus-nucleus scattering are compared with the amplitudes of the rigid projectile approximation in some simple cases. The calculated results show that the rigid projectile approximation is in general a good approximation of the Glauber theory.
The methods and results of papers (Ⅰ) and (Ⅱ) are applied to the interacting boson model (IBM) of nuclei. With the use of the SU6U5O5O3 representation the matrix elements of the phenomenological IBM Hamiltonian are expressed in terms of some "elementary matrix elements" of d-dosons. In accordance with the existing physical bases for d-boson systems and taking the SU2×SU2 representation as an intermediate representation, two types of formulas are constructed for the elementary matrix elements.
The working mechanism of the large area position sensitive ionization chamber for heavy ion nuclear reaction research is briefly described. The main part that is introduced is the experimental setup, electronics and data acquisition of the chamber which are used on 1.5 meter heavy ion cyclotron of Institute of Modern Physics, The experimental results of the chamber property measurement are also described for the 69.5MeV 12C and 93.5MeV 14N beams.
The problem of overcompleteness in the generator coordinate method is generally studied. It is shown that the effective operator (ON－1) as a whole excludes the coupliing between the physical and unphysical states and the problem of overcompleteness is resolved in this sense. This conclusion is illustrated with an example of boson representations of the SU(6) group.
A helix resonator providing a net voltage gain of more than 400kV at power levels of 19kW is lescribed. Some characteristics of the resonator at high power levels, such as static frequency shift and dynamic instability are studied experimentally. This helix resonator will be used as a booster for a 400kV Cockcroft-Walton generator.
Using the wave function of the independent α particle model & the eikonal distorted impulse approximation the quasi-elastic knockout reaction 12C(p, p α) 8Be at incident energy 100MeV is calculated. The theoretical results are in good agreement with the experimental data. It shows once more that the indepentent α particle model is reliable.
We propose some alterations for the 'tHooft's conditions and find a set of integer solution of index if the hypercolor gauge group is SU(3)×SU(3).
In this paper, Pauli-blocking effect in the optical potential derived from multiple scattering theory is discussed.
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