1986 Vol. 10, No. 5
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Abstract:
The method for the accurate determination of the small variation of positron lifetime spectrum parameters is described by the example of determining the positron lifetime variations by means of annealing in amorphous material. The comparison between the differential distributions by simulation calculation and by experimental measurement comfirms that the mean positron lifetimes in metallic glass Fe67Co18Si1B14 after annealing at 200℃,300℃ and 375℃ are 0ps, 4.0ps and 4.3ps, respectivly, shorter than that in the nontreated reference sample.
The method for the accurate determination of the small variation of positron lifetime spectrum parameters is described by the example of determining the positron lifetime variations by means of annealing in amorphous material. The comparison between the differential distributions by simulation calculation and by experimental measurement comfirms that the mean positron lifetimes in metallic glass Fe67Co18Si1B14 after annealing at 200℃,300℃ and 375℃ are 0ps, 4.0ps and 4.3ps, respectivly, shorter than that in the nontreated reference sample.
Abstract:
Plastic scintillators with many advantages are widely used in particle physics. Researches on plastic scintillator response at both high energy and high electric charge are significant to the experiments in high energy physics and cosmic ray physics. In addition to many important astrophysical results, the high energy cosmic rays experiments at the University of Chicago accumulate data for plastic scintillator response to relativistic particles of high electric charges. This paper introduces the cosmic ray experiments mentioned above, presents data analysis results and the discusses the nonlinear response of plastic scintillators.
Plastic scintillators with many advantages are widely used in particle physics. Researches on plastic scintillator response at both high energy and high electric charge are significant to the experiments in high energy physics and cosmic ray physics. In addition to many important astrophysical results, the high energy cosmic rays experiments at the University of Chicago accumulate data for plastic scintillator response to relativistic particles of high electric charges. This paper introduces the cosmic ray experiments mentioned above, presents data analysis results and the discusses the nonlinear response of plastic scintillators.
Abstract:
In this paper. the Bethe-Salpeter equation for spin (0—3/2) electromagnetic bound system is derived. Under the ladder approximation the approximate B-S wave function with accuracy up to order 0(α) for this system is obtained. Utilizing this wave function, we estimated the cross section for producing (π+Ω－) in Ω－-p collision process.
In this paper. the Bethe-Salpeter equation for spin (0—3/2) electromagnetic bound system is derived. Under the ladder approximation the approximate B-S wave function with accuracy up to order 0(α) for this system is obtained. Utilizing this wave function, we estimated the cross section for producing (π+Ω－) in Ω－-p collision process.
Abstract:
The nucleonic states are represented by different configuration components in Fock space and the transverse momentum of partons is introduced as a degree of freedom into the structure function. In this way We calculated the contribution of the components of the valent quarks and the non-valent quarks of the charm state to the ratio of the longitudinal and the transverse cross sections of the virtual photons. A better agreement with the experimental data is obtained. The causes of deviation of the Callan-Gross relation from the experimental data is pointed out.
The nucleonic states are represented by different configuration components in Fock space and the transverse momentum of partons is introduced as a degree of freedom into the structure function. In this way We calculated the contribution of the components of the valent quarks and the non-valent quarks of the charm state to the ratio of the longitudinal and the transverse cross sections of the virtual photons. A better agreement with the experimental data is obtained. The causes of deviation of the Callan-Gross relation from the experimental data is pointed out.
Abstract:
It is found that the zero-energy bound state of the superheavy fermion and SO(10) Monopole is possible. As a result we conclude that the Rubakov effect may exist in the presence of superheavy fermions.
It is found that the zero-energy bound state of the superheavy fermion and SO(10) Monopole is possible. As a result we conclude that the Rubakov effect may exist in the presence of superheavy fermions.
Abstract:
We applied the FF model of the quark-jet to the proton-proton soft collision and suggested a scheme for the diquark fragmentation. In this way we improved the two-chain model. The improved model not only can give the mean yields of various particles (such as meson, baryon, photon, quark-pairs, etc.) but also can calculated the single particle distributions and the correlations. The results are in agreement with experiments.
We applied the FF model of the quark-jet to the proton-proton soft collision and suggested a scheme for the diquark fragmentation. In this way we improved the two-chain model. The improved model not only can give the mean yields of various particles (such as meson, baryon, photon, quark-pairs, etc.) but also can calculated the single particle distributions and the correlations. The results are in agreement with experiments.
Abstract:
The pion's structure function behaviour is discussed by using the Fock state expansion of the hadronic wavefunction in QCD in this paper. As an example, we employ a model wavefunction of the Fock state in the light-cone and assume a Regge behaviour of a weight function for higher Fock states, and we get a possible form of the pion's structure function. This form is consistent with experimental data of the pion's structure function.
The pion's structure function behaviour is discussed by using the Fock state expansion of the hadronic wavefunction in QCD in this paper. As an example, we employ a model wavefunction of the Fock state in the light-cone and assume a Regge behaviour of a weight function for higher Fock states, and we get a possible form of the pion's structure function. This form is consistent with experimental data of the pion's structure function.
Abstract:
We calculate the angular distributions of elastic and inelastic scatterings from vibrational nuclei by using optical potential. The neutron and proton transition densities can be studied by comparing the π+ and π－ scattering on the nucleus. The importance of the virtual excitation of vibrational levels in calculating the differential cross section is discussed.
We calculate the angular distributions of elastic and inelastic scatterings from vibrational nuclei by using optical potential. The neutron and proton transition densities can be studied by comparing the π+ and π－ scattering on the nucleus. The importance of the virtual excitation of vibrational levels in calculating the differential cross section is discussed.
Abstract:
The magnetic field distribution of a C—type solid yoke bending magnet—a model magnet used on the Hefei synchrotron is measured and the eddy-current effects of a bending magnet on an electron storage ring during slow acceleration are investigated by two coil induction approach. When slow acceleration exists, possibility of applying a solid yoke bending magnet is verified.
The magnetic field distribution of a C—type solid yoke bending magnet—a model magnet used on the Hefei synchrotron is measured and the eddy-current effects of a bending magnet on an electron storage ring during slow acceleration are investigated by two coil induction approach. When slow acceleration exists, possibility of applying a solid yoke bending magnet is verified.
Abstract:
Some experimental results measured for light emission particles with Z≤2 from 12C+64Ni reaction at E(12C)=69, 56MeV are reported. A comparison between moving source model calculation and proton's spectra have been performed. Extracted parameters of the source with faster velocity are agreement with the systematic values found before. The composite particle energy spectra of α, 3He and D were analyzed by coalescence model.
Some experimental results measured for light emission particles with Z≤2 from 12C+64Ni reaction at E(12C)=69, 56MeV are reported. A comparison between moving source model calculation and proton's spectra have been performed. Extracted parameters of the source with faster velocity are agreement with the systematic values found before. The composite particle energy spectra of α, 3He and D were analyzed by coalescence model.
Abstract:
At C.M. angles 90°and 64°two-dimensional spectra of protons emitted from singlet deuterons were measured under such geometry where the kinematic ambiguty was small. From the data it is obtained that the breakup energy EB of the singlet deuteron state is (52+21)keV.
At C.M. angles 90°and 64°two-dimensional spectra of protons emitted from singlet deuterons were measured under such geometry where the kinematic ambiguty was small. From the data it is obtained that the breakup energy EB of the singlet deuteron state is (52+21)keV.
Abstract:
Angular distributions of fission fragment and fission excitations was measured for a series of reactions 12C+169Tm, 175Lu, 181Ta, W, Re, Pt, 197Au, Pb and 209Bi in the 57.0—73.0MeV energy region with mica detectors and gold surface barrier silicon detectors. The experimental values <Γf/Γn> we are abtained from fission excitation functions and compared to theoretical ones. The variation of the experimental values for the fission barrier height with the mass number A of the compound nuclei was studied and compared to the theoretical predictions by the liquid drop medel.
Angular distributions of fission fragment and fission excitations was measured for a series of reactions 12C+169Tm, 175Lu, 181Ta, W, Re, Pt, 197Au, Pb and 209Bi in the 57.0—73.0MeV energy region with mica detectors and gold surface barrier silicon detectors. The experimental values <Γf/Γn> we are abtained from fission excitation functions and compared to theoretical ones. The variation of the experimental values for the fission barrier height with the mass number A of the compound nuclei was studied and compared to the theoretical predictions by the liquid drop medel.
Abstract:
In this paper, an algebraic model, U(6)×U(11), is proposed for an unified description of the quadrupole-collective motion, the α-clustering and the octupole vibration. The model's three dynamical symmetries: SU(5), SU(3) and SO(6) are given. The spe ctrum of the SU(5) limit is calculated and compared with the experimental data of the nucleus 218Ra.
In this paper, an algebraic model, U(6)×U(11), is proposed for an unified description of the quadrupole-collective motion, the α-clustering and the octupole vibration. The model's three dynamical symmetries: SU(5), SU(3) and SO(6) are given. The spe ctrum of the SU(5) limit is calculated and compared with the experimental data of the nucleus 218Ra.
Abstract:
The general one body E2 operator is used to derive the analytic expressions of B(E2) from the first β and γ bands to the ground band under the SU(3) basis.
The general one body E2 operator is used to derive the analytic expressions of B(E2) from the first β and γ bands to the ground band under the SU(3) basis.
Abstract:
Magnetic field distribution, expressed in terms of coil parameters (geometric and current), of various kind of ironfree current wire elements is derived. A method for shaping and adjusting fringing field profile by the use of separated current wires which have different coil parameters is suggested, and the optimization of coil parameters is realized by the use of the method of least square. As an example, magnetic field profile of an iron-free magnetic β-ray spectrometer is shaped and adjusted to illustrate the use of this method.
Magnetic field distribution, expressed in terms of coil parameters (geometric and current), of various kind of ironfree current wire elements is derived. A method for shaping and adjusting fringing field profile by the use of separated current wires which have different coil parameters is suggested, and the optimization of coil parameters is realized by the use of the method of least square. As an example, magnetic field profile of an iron-free magnetic β-ray spectrometer is shaped and adjusted to illustrate the use of this method.
Abstract:
The matrix cap acity method used for the calculation of the electric field and the choice of the optimum voltages of the wires of the drift chamber used on the Beijing spectro-meter (BES) is described.
Abstract:
The structure function for nucleon is discussed by using the method given in a previous paper. The formula are compared with the experimental data from low Q2 to high Q2. The results show that the way that the structure function for nucleon can be obtained from the hadronic wavefunction is a possible approach of investigating structure functions for hadron.
The structure function for nucleon is discussed by using the method given in a previous paper. The formula are compared with the experimental data from low Q2 to high Q2. The results show that the way that the structure function for nucleon can be obtained from the hadronic wavefunction is a possible approach of investigating structure functions for hadron.
Abstract:
The spectra of primary cosmic ray nuclei are fitted from experimental data under 1014eV and extrapolated to their bending energies. The primary cosmic ray composition above 1014eV is deduced according to the rigidity cut off model by selecting an appropriate bending energy for proton so that the sum of various nucleus components is consistent with the experimental total particle spectrum. The method used is independent on the behaviour of hadronic interaction.
The spectra of primary cosmic ray nuclei are fitted from experimental data under 1014eV and extrapolated to their bending energies. The primary cosmic ray composition above 1014eV is deduced according to the rigidity cut off model by selecting an appropriate bending energy for proton so that the sum of various nucleus components is consistent with the experimental total particle spectrum. The method used is independent on the behaviour of hadronic interaction.
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