Vol. 26, No. 1 (1977)
1977-01-05
CONTENT
1977, 26 (1): 1-8.
doi: 10.7498/aps.26.1
Abstract +
A unified mechanism is proposed to explain the radiative decays and G-parity-conserving decays of the J particle into ordinary particles: According to this mechanism the J particle first decays into the intermediate state φn = αφ1+ βφ8, and then φn decays into ordinary particles. The following results are obtained:1. The predictions are in best agreement Math the experiment if φn≈ω, with the exception that the predicted ratio Γ(J →ω→ ηγ)/Γ(J →ω→πγ) is too small. 2. In order to fit both radiative decays and decays into two hadrons, the form factors for these two types of processes must differ by a factor 103. Using the straton model a method for calculating these form factors is given which explains the above difference quite well.3. Another possible mechanism of radiative decays of the J particle is also discussed, and some difficulties are pointed out.
1977, 26 (1): 9-15.
doi: 10.7498/aps.26.9
Abstract +
The 2γ width of X(2.8) which is observed as a decay product of J (3.095) can be determined from high energy Coulumb photoproduction of this particle on nu-cleons and nucleus. The pertinent Feynman diagrams are discussed, the related coupling constants are analized and estimated, and the differential photo-production crossections from 0-3° of 50 and 100 GeV γ on proton (and also 100 GeV γ on the nucleus of lead) are calculated. The results show that if the decay width is not much less than 1 keV, then it can be determined accurately by this Coulumb photo-production measurement.
1977, 26 (1): 16-21.
doi: 10.7498/aps.26.16
Abstract +
A procedure is proposed for the experimental determination of the spin-parity of the new particle X(3410). It consists of choosing the events representing the radiative decay ψ→X(3410) +γ from the ψ-production experiment at s1/2 = 6.84 GeV, and measuring the angular distribution of the y photon produced in the process, and also the energy distribution of two pseudo-scalar mesons from the subsequent decay of X. The result of calculation shows that the spin-parity of X(3410) can be determined with certainty and good sensitivity.
1977, 26 (1): 22-33.
doi: 10.7498/aps.26.22
Abstract +
The principles and experimental results of a frequency spectrum analyzer for all types of single transient processes are described in this paper. By the suitable combination of existing laboratory instruments and a few special circuits which are described here, the analyzer may be assembled fairly quickly. By using time expansion (or compression) techniques, the frequency spectrum of interest may be trans-fered to any frequency band. The single transient is reproduced as a repetitive waveform by means of a photoformer. In this way it is possible to use an ordinary low frequency spectrum analyzer to measure the frequency spectrum of single transient processes of any type or duration. Experimental results prove that the above method is applicable. For the principal compositions of the spectrum, measurements may attain an accuracy of 2-3%. The accuracy for minor compositions of the spectrum is somewhat less.
1977, 26 (1): 34-53.
doi: 10.7498/aps.26.34
Abstract +
A combined magnetic round lens and deflection system with a superimposed field has been studied, and the power series expressions for the magnetic field is given. The electron trajectories are described in vector-form, and the Gaussian optical properties of the combined system discussed. By means of Fermat's principle general aberration formulae for the combined system have been derived. Equations for calculating the third-order aberration are given in compact matrix-form, hence they are suitable for numerical computation. This paper attempts to give a general theory of the combined system to provide guidance for designers of cathode ray tubes and electron optical instruments.
1977, 26 (1): 54-63.
doi: 10.7498/aps.26.54
Abstract +
The coherent structures of two phonons have been proposed as the sub-structure α+ of four-particle clusters for the light nuclei. In the same way the sub-structure β+ of four-hole clusters can also be given. Based on this the sub-structures between particle clusters and hole clusters in 16O and 18O have been chosen as examples for our investigation. It is found that there is a very strong repulsive force between them. Therefore the loose structure between particle cluster and hole cluster is of the lowest energy state. In this way, the deformations of these states have been explained from the microscopic structures. Moreover, these strucrures can coherently strengthen the E2 transition. Further in order to study the particle correlation in the medium nuclei, the L-S coupling coherent structure is extended to the pseudo L-S coupling coherent structure and the expressions are given in the j-j coupling representation. Some preliminary analyses are made for the nuclei around 56Ni by using these structures.
