1986 Vol. 10, No. 6

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Review
AN ANALYSIS OF PRIMARY COSMIC RAY COMPOSITION AT ENERGIES AROUND 1014eV USING SINGLE-SHOWER EVENTS OBSERVED BY MOUNTAIN EMULSION CHAMBER
HE Yu-Dong, ZHOU Wen-De, HE Ren-Dao, MU Jun, DING Lin-Kai, ZHU Qing-Qi, JING Cai-Liu, JING Gui-Ru
1986, 10(6): 641-646.
Abstract:
The characteristics of electromagnetic and hadronic components in high energy cosmic rays at mountain altitude are studied by analysing single-shower events observed by mountain emulsion chamber. The chemical composition of primary cosmic rays in the energy region around 1014eV is studied by using Monte-Carlo simulation. The simulated power indices of energy spectra and attenuation lengths in air in agreement with the experimental data. The analysis of their vertical intensities indicates that the chemical composition of primary cosmic rays at energies around 1014eV is not contradicted to the simple extrapolation from lower energies and the abundance of protons can not be less than 30% and that of the nuclei with A≥2 not larger than 70%.
THE FORMATION CROSS SECTION FOR () ATOM IN RADIATIVE CAPTURE PROCESS
SONG Xiao-Tong, CHEN Zheng
1986, 10(6): 647-655.
Abstract:
Under the ladder approximation, the B-S equation for () atom is derived and the approximate solutions for l=0 are obtained. By using these solutions, the formation cross sections for the () atom in the radiative capture process are calculated.
GREEN FUNCTION FOR RELATIVISTIC SCHRÖDINGER EQUATION
WEI Hua, RUAN Tu-Nan
1986, 10(6): 656-665.
Abstract:
Using Schrödinger wave function in quantum field theory, the time-dependent Green function and its spectral representation for 2-fermion system are derived, and the Schrödinger equation as well as the normalization condition of his wave function are deduced. The normalization condition shows that this wave function in just the probability amplitude when energy-dependence of potential can be neglected. The Green functions for some other equal-time equations are evaluated, however, the normalization of these equations remains to be solved and the potential is non-Hermitian.
ADLER-BELL-JACKIW ANOMALY IN LATTICE GAUGE THEORY
CHEN Hao, GUO Shuo-Hong
1986, 10(6): 666-676.
Abstract:
The axial anomaly in lattice gauge theory with Wilson fermion is discussed. Under weak coupling approximation, we calculate the anomaly term systematically by path integral method. The result agrees with that obtained in continuum theory.
THE EFFECTIVE INTERMEDIATE RANGE INTERACTION IN BARYON SPECTROSCOPY AND ITS EFFECT ON N-N INTERATION
HU Bing-Quan, HE Qi-Zhi, ZHANG Zhao-Xi, AN Ying
1986, 10(6): 677-683.
Abstract:
In this paper, we introduce the phenomenological quark-quark intermediate range potential to fit the non-strange baryonic syectrum with N≤2 on the basis of the model of one-gluon exchange with a confining potential. It is shown that the calculated position of the resonanses below 2GeV can be in good agreement with experiments by taking an appropriate quark-quark intermediate range potential. The N-N interaction is also investigated with this new phenomenological potential.
WHY CP VIOLATION IS VERY SMALL IN THE STANDARD MODEL OF ELECTROWEAK THEORY
WU Dan-Di
1986, 10(6): 684-689.
Abstract:
By using the nontrivial rephasing invariants Δia of the KM matrix, all the factors which suppress CP violation effects in the standard model with three generations are discussed. They are: Im Δia/γ (KM), the uneveness in magnitudes of two quantities whose weak phases are going to be compared, the effects of strong phases, etc. The arguments are supported by examples.
PION INELASTIC SCATTERING ON 12C AT 800MeV/c
CHEN Ke-Zhong
1986, 10(6): 690-696.
Abstract:
In the framework of Glauber theory the recent pion inelastic scattering data on 12C at 800MeV/c are analysed by using the transition density method. The degree of agreement between the theoretical results with different parameters and the experimental data are discussed. The Coulom effect for pion-12C inelastic scattering is also considered.
RESEARCH ON THE TRANSVERSE STABILITY OF THE CENTRAL BEAM IN A WAKE FIELD ACCELERATOR
WANG Shu-Hong
1986, 10(6): 697-703.
Abstract:
The principle of the wake field accelerator is summarily described. Special emphasis is put on the transverse stability of the central beam. A limitation of the central beam by using solenoid is presented. The efficiency to stabilize the central beam by means of a "Continious" and optimized focusing system is researched.
MEASUREMENT OF THE COMPLETE FUSION EXCITATION FUNCTION FOR 12C+28Si REACTION
ZHENG Ji-Wen, LIANG Guo-Zhao, LIU Hong-Tao, BAI Xing-Ping, MA Jun, YAN Jian-Gang
1986, 10(6): 704-710.
Abstract:
The excitation function for 12C+28Si complete fusion reaction was measured in incident energy 43—70.5MeV with a ΔE-E counter telescope. The experimental complete fusion excitation function shows some gross oscillation structures. The mean behaviour of the experimental data fits the potential model and the statistical Yrast line model well.
A CONSTRUCTIVE INTERFERENCE EFFECT IN THE CHANNEL RADIATIVE CAPTURE PROCESS
HUO Yu-Kun, LIU Jian-Feng
1986, 10(6): 711-714.
Abstract:
The radiative capture cross section at thermal neutron energy in 40Ca, 410mb, is much higher than that expected by the statistical theory as well as by the direct capture theory. This study shows that this is a result of the constructive interference between potential capture and valence capture. By using the Becchettic-Greenless optical model potential[7] and in-cluding the interference effect, the thermal neutron induced radiative capture cross section and scattering cross section in 40Ca were calculated and compared with measured data.
THE QUADRUPOLE OPERATOR IN s-d-g MODEL AND THE SPECTRUM OF DEFORMED NUCLEI
WU Hua-Chuan
1986, 10(6): 715-719.
Abstract:
In this paper, the spectrum variation of the deformed even-even nuclei which deviate from the SU(3) limit of the U(15) model is discussed. It is shown that the probability of the g-boson is crucial for some features of the spectrum structure.
SHORT-RANGE REPULSION AND PARAMETERS OF NN INTERACTION
WU Guang-Han
1986, 10(6): 720-729.
Abstract:
After evaluating NN scattering phase-shifts of (s,t)=(0,1),(1,0),l=0.2 with two sets of parameters, the contributions of specific terms of qq interaction or specific exchange mechanisms to the short-range NN interaction are analyzed.
SPATIAL DISTRIBUTION OF MAGNETIC FIELD EXPRESSED BY THE FIELD ON MERIDIANAL PLANE
LI Zeng-Hai, MAO Nai-Feng, LIU Lan-Fen, SUN Qin-Ren
1986, 10(6): 730-737.
Abstract:
A general expansion in Taylor series of space magnetic field (median plane symetry or nonsymetry) expressed in terms of the field in the φ=φ0 meridian plane, which may be expressed analytically or by field values at discrete nodes, is derived in cylindrical coordinate system.
THE VALIDITY OF M-3Y FORCE EQUIVALENT G-MATRIX ELEMENTS FOR CALCULATIONS OF THE NUCLEAR STRUCTURE IN f-p SHELL
WANG Zi-Xing, SONG Hong-Qiu, CAI Yan-Huang, HUANG Wei-Zhi
1986, 10(6): 738-743.
Abstract:
By using the matrix elements of M-3Y force as the equivalent G-matrix elements, the spectra of 42Ca and 42Sc are calculated in the framework of the Folded Diagram Method. The results show that such equivalent matrix elements are suitable for microscopic calculations of the nuclear structure in f-p shell.
SINGLE-PARTICLE AND SINGLE-HOLE SPECTRA IN 40Ca
JING Xiao-Gong, LI Cheng-Zu, YANG Shan-De, WU Shi-Shu
1986, 10(6): 744-751.
Abstract:
The single-particle (sp) and single-hole spectra in 40Ca are calculated with the Paris potential by two methods: (1) the eigenvalue equation derived from the sp Green function and (2) the sp potential uαβ=Mαββ) defined in terms of the mass operator Mαβ(ω). The energy dependence of G-matrix is taken into account rigorously. Our results agree with the experimental values fairly well. It is found that the Paris potential yields a somewhat better result than the RSC potential.
ESTIMATION OF ENERGY LOSS dE/dX AT MAIN DRIFT CHAMBEROF BEIJING SPECTROMETER
MAO Hui-Shun
1986, 10(6): 752-756.
Abstract:
For the main drift chamber of Beijing Spectrometer, the most probable energy loss and particle identification capability for π, k, p, e are evaluated by using phenomenological approach. A simulation calculation with Landau distribution is also made.
THE STOCHASTIC DECAY OF FIRE BALLS AND THE HYPOTHESIS OF LIMITING FRAGMENTATION
WU Yuan-Fang, LIU Lian-Shou
1986, 10(6): 757-760.
Abstract:
The "scaling in fragmentation region" given by UA5 Collaboration in pp Collider (SPS) experiments is investigated. It is pointed out that these phenomena support the limiting fragmentation hypothesis. The calculated results by using the stochastically decaying fire ball model fit the experimental data remarkably.