1985 Vol. 9, No. 4
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A study of the anisotropy of primary cosmic raya is presented. The expression of the anisotropy is derived in a model of statistical discrete sources in an infinite galaxy. Using these derived formulas, the amplitudes of the first harmonic anisotropies caused by eleven supernovea nearby the Earth are estimated individually and the trend of the resultant anisotropy is investigated. It is found that the expected results can account for the power law of E0.5 of the anisotropy above the energy 5×1015eV. The Compton-Getting effect can cause an additional anisotropy which is independent of energy and added to the resultant anisotropy of these discrete sources. It is apparent that the anisotropies available in the low energy range 1011—1014eV are caused by the Compton-Getting effect. Taking the differential spectrum index γ=2.67 mersured in the same energy bound we get the streaming velocity of 35km/s with respect to the cosmic ray background.
We have observed the arrival times of EAS initiated by cosmic rays of E>1014eV using the EAS array in Beijing. The distribution of arrival time intervals of EAS With E>2.6×1014eV is considerably higher than the exponential distribution in the region of time interval t<21 second. It is suggested that a time correlation component is probably present in the EAS events.
The testing results on a SQS gas sampling shower counter with cosmic rays are reported. The measurement shows that this detector can clearly reconstruct the tracks of cosmic ray charged particles. The position resolution is better than 0.6% (450cm fullscale), and it may be further improved to reach 0.3%. Based on the investigations of minimum ionizing particle charge spectrum we may expect that the energy resolution of this type of shower counter could be 15%/√E.
In this paper we discuss the U(5) limit of U(6/20) supersymmetry in nuclei. First we discuss the reduction of the relevant group chain. Then we discuss the dynamical symmetry in the case of M=1. Finally we make comparison between the theoretical calculation and experimental measurement in the case of nucleus 10344Ru59.
In this paper the SLAC bag model is discussed by using the method of fermion coherent state. The results agree with the SLAC bounded state solution, so that quark confinement can be illustrated. In addition, a non-quark bag solution and a non-bounded state solution, which are absent in SLAC theory, are found.
An SO(10)×SO(8) model of grand unified theory is proposed. It can accommodate the color singlet particles with fractional charges (for example: e/2 or e/3), and the model satisfies the Dirac quantization rule with magnetic charge 1/2e. This theory predicts four generations of ordinary fermions and four generations of peculiar fermions. In particular, there exist peculiar photons which are different from ordinary photons. These could be tested in future experiments at high energy.
Using dimensional regularization, we show by explicitly calculation to the one-loop level that the validity of the axial vector Ward identities in SU(2)L×U(1)Y model which contains heavy leptons and is free from Adler-Bell-Jackiw(ABJ) anomalies is independent of two definitions of γ5 in n dimensions. A natural corollary is that the method of the dimensional regularization is suitable to the model in which there exist axial vector coupling fermions. When AVV triangles are embeded into the vertices of axial vector fermions, we find that in physical limit n→4 they do not induce any new finite anomalies. We therefore show that to at least two-loop the conjecture originally raised by Frampton that there exist new mass-dependent anomalies is also incorrect in the non-Abelian case.
The contributions from the valence quark state and the higher Fock states of hadronic wavefunctions in the process π0→γγ are analyzed in this paper. An important result, the contribution to the amplitude of the process π0→γγ from the valence Fock state is one half of the total amplitude, is proved by using a gauge invariant identity of the divergence of the axial vector current. From this inference we obtain a constraint on the valence Fock state wavefunction, which is very useful for useful for phenomenological analysis in exclusive processes.
In this paper, we derive the Λ-N S wave separation potential from the scattering lengths and effective ranges obtained from the Λ-N single K, η, ω and 2π, πρ meson exchange potential. Based on calculating the S wave phase shift of Λ-p elastic scattering and the Λ well depth in nuclear matter, the features of the Λ-N S wave separation potential are discussed.
The α-particles induced by 6.8MeV/A—5.1MeV/A 14N on 59Co and 51V targets were measured using ΔE-E semiconductor telescope. The energy spectra, the angular distributions and the contour plots of d2σ/dΩdE in the E-θ plane were obtained. The direct α-particles and the compound evaporation α-particles were seperated. The possible mechanism of the direct α-particle emission is discussed.
The experimental results of sequential fission are presented for collision of 238U (5.4MeV/u) on 48Ca,45S and 238U(6.0MeV/u) on 16O,48Ca,45Sc,48Ti,58Fe,64Ni and 89Y targets. The measurements of ternary events in exit channel have been performed by triple coincidence among 4 PPAC with area of 20 cm×30 cm. The reconstrction of ternary events are performed by direct kinematics and the fission partner among three fragments is identified by relative velocities between them. The detection geomentry efficiency is determind by a Monte-Carlo simulation.
Before the sequential fission, U-like fragments are scattered near grazing angle. The most probable value of TKEL in the scattering process associated with S.F.changes from 25 MeV to 55 MeV for different reaction systems. The angular distributions of debris of S.F. in second C.M. are isotropic.
In conclusion, because of lower fission threshold at Uranium region, the sequential fission mainly follows quasielastic scattering, in S.F. cross-section σS.F there is strong shell effect. A simple relationship between σS.F over σR, the total reaction cross-section and Sommerfeld parameters S for nuclei with magic number are obtained.
In this note the relation between IBM-Ⅰ and IBM-Ⅱ is briefly discussed from the F-spin symmetry. In order to discuss the symmetry breaking quantitatively, the Hamiltonian is divided into two parts: one is F-spin symmetric and the other breaks the F-spin symmetry. Finally the methods for calculating the relevant matrix elements are provided. This work essentially is another scheme for IBM-Ⅱ.
The color-analog Van der Waals force between two hadrons is studied by use of the coupling channel resonating group method in the framework of the Gaussian-type quark confinement potential. The problem of the boundary values for the two channel coupling differential equations is changed to the problem of the initial values. The equations are solved numerically by use of the Gear method. The calculated results show that there is no color Van der Waals force between hadrons in the confinement potential model. This indicates that the confinement potential model not only can describe the internal structure of hadrons but also can be used to calculate the hadron-hadron interactions if the quark confinement potential is chosen properly.
A mapping between the SU6 subspace of the S-D boson states in the interacting boson model (IBM) of nuclei and the SU6 subspace of the b-boson states as proposed by D.Janssen et al. is established. It is shown that under the mapping the SU6 infinitesimal operators and the Hamiltonian of the IBM are transformed into the corresponding operators as proposed by D.Janssen et al. Furthermore wave functions of the b-boson states corresponding to the three dynamical symmetries in the IBM are constructed.
Possible filling up of 27 dimensional representation of SU(3) by pp,pn,Λp,Σ－p,ΛΛ and Ξ－p dibaryon resonant states is proposed. The theoretical results agree with the experimental ones very well. Possible existence of other dibaryon resonant states as well as their characteristics are disussed.
Using the VMI model for the calculations of alignment angular momenta of nuclei 156Er and 162Er, it isn't difficult to discover that there are different shape transitions for nuclei 156Er and 162Er when a pair of nucleons are dispaired and aligned.
In this paper, a new technology about self-quenching streamer counter-induced readout with resistive eathode, some characteristics and preliminary results are introduced. We have investigated the influence of wire diameter, dead time on plateau curves, using different gas mixture filled in the tube (Ar/C4H10, Ar/CH4 and Ar/CO2) as basic working gas. The relations between content of various quenchers (H2C(OCH3)2, C2H5OH, C6H6 and C7H12), plateau curves and the efficiency and dead time of the tube were measured.
A large area plastic scintillation counter(100×20×1cm3) for TOF measurement has been made and the performance of this counter has been measured. A self researched new type Mean-Timer was used to much better eliminate the time difference of the fluo-rescence light transmission in the scintillator generated by the different location of the injecting particles, obtained time resolution of scintillation counter is about 347 ps.
For SU(3) lattice gauge theory two alternative actions proposed by us are studied by means of Monte Carlo method, their internal energy per plaquette and specific heat are calculated. The curves of their internal energy approach to the same weak-coupling approximation when is large, there are peaks on their specific heat curves. The deviation of the peaks of the specific heat owing to the difference of higher order terms of lattice spacing a is observed.
In the framework of the SU(2)×U(1) gauge theory, we assume that there are two left-handed doublets, and tow neutral singlets of leptons After the spontaneous symmetry breaking, we have electron and its neutrino, a new charged heavy lepton and its neutrino, two neutral heavy leptons. We assume that the mass of the charged heavy lepton is between that of Z0 and W, and at least one of the neutral heavy leptons has a larger mass, then the radiative decay of Z0 can be understood.
Recently, a kind of proton synchrotron with high repetition rate is developed and comes into wide use. But this leads to more severe requirements on the ferrites which are used in the RF system in accelerators. One of them is the time response. In this paper, the characteristic of time response and the measurement method are presented.
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