1984 Vol. 8, No. 4
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Using a very light silica aerogel sample as the o-Ps source to reduce the scattered γ rays and a high purity Ge (HPGe) γ energy spectrometer with a precise timing channel for event selection, the continuous γ ray energy spectrum from o-Ps 3γ decay has been measured in the whole spectrum range. The result is in a good agreement with the result of Ore-Powell theoretical calculation.
Both fast and slow components from a BaF2 scintillator made in Artifitial Crystal Institute of China have been observed. The properties such as light yield, time resolution, energy resolution, energy linearity, technical attenuation length etc have been measured. The time resolution (σ) equal to 59ps for γ-rays from 60Co source; The energy resolution equal to 12.1% for γ-rays from 137Cs source. These paremeters approach advanced level. The properties of BaF2 crystal show a bright future in the application of BaF2 to nuclear physics, nuclear medicine and particle physics.
The unfolding and folding methods are generally used in the radiative corrections to the electron inelastic scatterings. In this paper, the R-function method is introduced which can be used to transfer the radiated cross section σrad to the non-radiated cross section σnon or vice versa. In addition, in the polarized experiments R-function method can be used to transfer the radiated asymmetry Arad to the non-radiated asymmetry Anon or vice versa.
In this paper we point out that the Ernst equation can be reduced to the principal chiral model. We discuss the relations for axially symmetric SDYM and Ernst equation as well as principal chiral model. The correspondens in the Ernst equation presented in SDYM is also discussed.
In this paper the coherent state which possesses a definite Abelian charge is extended to the case of possessing a definite non-Abelian charge. The SU(3) charged, hypercharged coherent states for both boson and fermion cases are constructed. In this way, the fractionally charged, hypercharged quark states can be obtained naturally. Moreover, this formulation also shows that in order to obtain integrally charged, hyper-charged hadron coherent states, one must introduce color quantum number and proceed the discussion of the SU(6)×SUc(3) case.
The correlated nuclear model can describe high energy hadron-nucleus scattering at large angles very well. But in many papers, the inelastic effects which may be as important as correlations are neglected. In this paper, we include double inelastic processes in hadron-nucleus elastic scattering and obtaln a simple formulae for this scattering. We also calculate 1GeV proton-C12 elastic scattering differential cross sections. The results show that the inelastic effects are not important quantitatively for small angles.
In this paper, the equivalent interactions as one meson exchange between two quarks, three quarks and four quarks are derived from the one gluon exchange transition potential Vq→qqq by using the closere approximation. One can expect that this approach will be quite useful to add the sea-quark in studying the N-N interactions based on the quark potential model.
In the framework of two nucleon absorption, we analyse the nucleon spectra sollowing pion absorption by 4He for stopped pion and pions in flight at Tπ=60, 100 and 220 MeV. Two nucleon absorption mechanism agrees quantitatively with the data. Four nucleon phase space calculation does not fit the measurements.
The vibrational-rotational band structure of the collective excitation spectrum in even-even deformed nucleus was established in previous paper. In this formulation the expression of the ground band spectrum can be written approximately in a closed form of two parameters. Using this new expression the ground bands of several typical even-even deformed nuclei are analyzed systematically. The calculation is in a agreement with the experiment. The variation of the nuclear deformation with the angular momentum is discussed in some detail.
Based on an analysis of Kramers' stationary solution, by means of the analytical solution of the Fokker-Planck equation in a harmonical potential, we propose a simple model for the calculation of the fission rates. As an example we compute the time evolution of the fission widths of Pu240 for various finite friction values and compoared our results with the corresponding ones based on Kramers' formula for a large and small frictions and the transition state method.
Using the GCM method and taking the coupling between collective octupolevibration and noncollective particle-hole configurations into account, the quadrupole moment Q(3－), the reduced octupole transition probability B(E3) and the variation of the transition density ρtr3 with respect to the radial distance are calculated. We found that Q(3－)－0.098eb and B(E3) =38 w.u.. It is shown that the desired results can be obtained by taking the core-excitation into account microscopically in the GCM framework without introducing the usual effective charge of nucleons.
The wave equations for the channelling relativistic electron and positron are solved by W.K.B. method. Taking Moli´ere potential, the planar channelling radiation spectra of electrons are calculated. The calculations agree well with the experimental results. A multiplicity of the radiation spectrum for the relativistic positron is predicted and an explanation is given for the single peak observation. More accurate wave functions for the channelling particles have been derived by perturbation theory. Channelling radiation selection rules are obtained and the relative intensities of electron radiations from different energy level transitions are evaluated. The quantum effects of radiation spectrum shift for ultrarelativistic channelling positron and electron are also discussed.
We summarize the use, circulation, construction, measurement, control and safety precuusion of the liquid hydrogen target. The volume of the liquid hydrogen target is 0.3 1. As soon as it is started it can be running without being taken care of. It can be used in any laboratory which needs it.
In heavy ion reactions, the intermediate structure phenomena show the properties of the rotation-vibration spectra of molecules. In this paper, these rotation-vibration spectra are classified by the irreducible representation of group U(5). The calculated result show that the symmetry of rotation-vibration spectra for nuclear molecule are described by the algebra of U(5) quite well.
The exponential model of the nuclear moment of inertia proposed by P.C. Sood and A.K. Jain is improved, and a new expression for the rotational bands of an even-even nucleus is proposed. The backbending and the downbending behaviours in J vs ω2 plot can be reproduced by the calculations based on this new formula.
The Monte-Carlo simulation of production and transmission of photons in the prototype of end cap time of flight (scintillation) counter is described. The simulation results agree with the experimental data.
Using the harmonic oscillator wave function with D-wave component to describe the niternal wave function of deuteron, a analytic solution in closed form the p-D high energy elastic scattering amplitude is derived. The calculated differential cross section can fit experimental data if include the D-wave of deuteron.
Energy spectrum of cosmic rays ranging from 6×1014 to 5×1016eV is studied. The work is done automatically by employing a computer as well as fast and efficient electronics. The results of the experiment show that: The integral spectrum of the primary cosmic rays can be represented as I=K.(E/E0)－γ The value of γ is changed from 1.15±0.04 to 1.19±0.08 at energy around 3×1015eV.
Both the symmetrical anomaly and the unsymmetrical anomaly are derived from an effective Lagrangian recently constructed on the basis of Chern-Simons topological invariants.
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