1993 Vol. 17, No. 7

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A New Decay Channel Discovered in β-Delayed α Decay of 20Na
XU Xiao-Ji, GUO Jun-Sheng, HU Zhi-Qiang, ZHOU Xiao-Hong, MA Rui-Chang, LIU Hong-Ye, LI Gui-Sheng, DU Yi-Fei
1993, 17(7): 577-581.
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.
Study on the Localization Properties in Self-Quenching Streamer Multiwire Chamber
CHEN Hong-Fang, XU Zi-Zong, HONG Bao-Sen, GUO Guang-Hui, ZENG Hui
1993, 17(7): 582-588.
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.
Monte Carlo Simulation for the Propagation of Galactic Cosmic Ray Nuclei
ZHANG Li, ZHANG Ming, MU Jun, YU Chuan-Zan
1993, 17(7): 589-594.
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.
Design and Initial Performance of Zhengzhou EAS Array
SUN Luo-Rui, GUO Zheng-Yuan, ZHAO Shu-Jun, YUE Xue-Dong
1993, 17(7): 595-600.
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.
Studies of the Wide Resonance θ(1720) in J/ψ Hadronic Decays
YU Hong, SHEN Qi-Xing, ZHU Yu-Can, ZHENG Zhi-Peng, CHENG Zheng-Dong
1993, 17(7): 601-604.
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.
The Non-Abelian Wormholes Solutions in Baby Universe Model
YAN Jun, TAO Bi-You, HU Shi-Ke
1993, 17(7): 605-613.
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.
ρ0-ω Mixing Effect in the (ρ0,ω)→e+e Pair Decay
LIU Liang-Gang
1993, 17(7): 614-618.
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.
Distribution Functions of Vector Boson
XU Zai-Xin
1993, 17(7): 619-625.
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.
Extension of the Linear Self-Dual Constraint Theory and Its Quantization
MIAO Yan-Gang
1993, 17(7): 626-630.
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)
CHEN Yong-Qing
1993, 17(7): 631-635.
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.
Accurate Calculation of Superdeformed Bands in Hg and Pb
LEI Yi-An, ZENG Jin-Yan
1993, 17(7): 636-643.
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.
Heavy Ion Collision Dynamics in Fermi Domain (Ⅲ) Multifragmentation and Limiting Exciting Energy
ZUO Wei, GE Ling-Xiao, ZHANG Feng-Shou
1993, 17(7): 644-650.
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.
The Effects of Different Kinds of Confinements and Configuration Space on N、Δ Spectra
DONG Yu-Bing, YU You-Wen
1993, 17(7): 651-657.
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 of 20Ne+20Ne at 25MeV/A
ZHU Quan-Ling, GE Ling-Xiao
1993, 17(7): 658-664.
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.
On the Deep Optical Potential and the Parity-Dependent Effect between Heavy-Ions
GAO Cheng-Qun, YANG Bao-Sheng, ZHOU Quan-Hua
1993, 17(7): 665-672.
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.