1988 Vol. 12, No. 5
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Results are presented on the properties of Chinese zinc tungstate crystal for detection of photons,which include absorption and emission spectram,relative light yield to NaI (Tl),energy dependence of the energy resolution,linearity of energy response and temperature dependence of the light yield.
The preliminary data of the interaction free path distribution and the multiplicity distribution of projectile α-fragments in Kr-emulsion collisions at 1.4A GeV are presented.
In this paper a method of detecting the pionic nuclear radio-activity discussed by Ion et al.is proposed using in clusive high energy gamma ray measurement.Taking the maximum pion energy given by Ion et al,the energy ranges of the gamma rays from the emitted π0 mesons are calculated.
This paper reports the study and production and the performance of 60 PWC's which were the first module of L3 hadron calorimeter.125 Volts plateau and 3.4%/100V plateau slope were obtained with the gas mixture of Ar:CO2=80:20.We also checked the dark current of some chambers and found that the dark current could be reduced by "cooking".The chambers worked well when they were assembled in a calorimeter module and tested by the beam of SPS at CERN.
The effective Lagrangian of chiral QCD2 in 1+1 dimensional curved spacetime is derived by using pathintegral approach.It is shown that vector bosons may have a mass generation and interaction of gravity with gauge field may exist.Besides,the effective Lagrangian contains a term corresponding to the analog of the gauged Wess-Zumino-Witten term in 2-dimensional flat space-time.
In this paper,we have calculated the SU(2) lattice gauge by the Monte Carlo method.For the finite temperature problem 83×4 lattice is used and for the zero temperature problem 84 lattice.From the calculations of the energy density,heat capacity and entropy density,the results indicate that there is a deconfinement phase transition when T/ΛL=40—50.
By using the cumulant expansion variational method,we study the SU(2) lattice action including six-link loops which satify the request of Symanzik.The average values of the plaquette and six-link loop up to second order approximation are calculated.Our results are consistant with Monte Carlo data.
In this paper we study a modified skyrme model with mπ≠0 and compute the static properties of nucleons in this model.The results show that most of theoretical values have been improved,especially
We calculate the short range part of π+-π－,K+-K－,K+-π－ and K－-π+ potentials by using both the conventional quark-antiquark annihilation mechanism and the hybrid medium state model.The result of the scattering length for π+-π－ channel favors the hybrid medium state model.
In the framework of fixed-scatterer field theory,we construct the second order iso-elastic microscopic pion-nucleus optical potential by including two nucleon correlation.The double charge exchange reactions to the double isobaric analog state are calculated by using our theoretical optical potential.For the incident pion energies ranging between 0 and 300MeV,the s and p wave components are included in the πN amplitude.
Relativistic microscopic optical potential of a nucleon above the fermi sea based on Walecka's model is used to systematically analyze the proton elastic scattering from nuclei at energies below 300MeV.It is shown that the experimental data of differential cross sections,analyzing powers and spin rotation functions are reproduced satisfactorily except for large angles.This simple model might be used in the nuclear transport theory and heavy ion collision to take account of both nuclear medium and relativistic effects.
For a system described by the interacting boson-fermion model (IBFM),we construct the intrinsic states and study the moment of inertia of deformed odd-A nuclei in terms of the selfconsistent cranking calculation.An approximate analytic method for the energy spectrum is presented in the general cases where the IBFM Hamiltonian does not have dynamical symmetry.The rationality of this method is also discussed by taking 153,155,157Eu isotopes as examples.
The betatron tune spread caused by magnetic field errors in accelerators is a very important parameter.In this paper a expression of middle plane asymmetrical magnetic field errors is obtained on the Maxwell equations,and a general formula formula of tune spread is derived starting from the transverse equations o motion.
The fission cross sections and the evaporation residue cross sections for 12C+209Bi and 14N+Pb reactions were measured with the gold surface barrier silicon detectors and the mica nuclear track detectors.The critical angular momentum ler was deduced from the measured evaporation residue cross section σer on the basis of the sharp-off model.The fission barrier with the particular angular momentum i derived from the condition Γf/Γn=1 at l=le The angular momentum effect of the fission barrier was studied experimentally.
Based on the approximate consideration suggested by Bohr and Mottelson,in which the moment of inertia is effected by paring correlation and depended on the deformation,the values of the nuclear deformation were extracted from the experimental effective moment of inertia,and it has been compared systematically with theoretical results and the values extracted from electronic quadrupole moment.It is shown that Bohr and Mottelson's consideration is reasonable.
In the paper,large deformation of symmetry fission has been described by a biquadratic surface revolution instead of several quadratic equations.Based on the standard liquid drop model,variation calculation of deformation energy have been performed,a better shape with a gruop of coefficient (bi) than Cassinian ovaloid obtained.The shape with (bi) has lower deformation energy than that of ovaloid,at same separation distances between C.M. of half bodies.The so-called shape optimum Ⅱ with (bi) can generally be used in mass range 200—300. The fission barrier for opt.Ⅱ is lower and thiner than that of the ovaloid,because after the saddle point the potential descends more quickly.The saddle point is a little bit pressed for the shape opt.Ⅱ.There are significant differences of deformation energy between the shape opt.Ⅱ and ovaloid,when neck in middle appears.The neck cross-section of the opt.Ⅱ is larger than that of ovaloid before the scission point be reached,and equal or thiner near the point.
The possibility that the tribaryons including 3He and 3H belong to an SU(3) 35 dimensional irreducible representation is suggested.We calculate the wave functions and the branching ration of the 35-plet of the tribaryons.The mass relations of the tribaryons in multiplet are obtained.The possible tribaryon states are predicted.
The (n,2n) and (n,3n) reaction processes have been studied by mechanism analysis of the neutron-induced nuclear reactions,formulae for evaluating the reduced cross section have been given.The cross sections of 14.5MeV (n,2n),(n,3n) reactions have been calculated according to the systematic method for Z=58—83 about 53 nuclei.A good agreement between the results of the systematic calculations and the experimental data has been reached.
With increasing the rotational frequency ω,the seniority V-structure and the K-structure of the CSM wave function become very complicated.For not too high ω(hω≤0.5MeV) configurations with V=0,2,4 are dominant for the low-lying bands,while those with V≥6 are negligibly small.Configurations with various K-values (│K│≤10) are comparable and the nucleus deviates from axial-symmetry significanly.The variation of the gap parameter with ω are analysed also.
According to microscopic consideration,the coefficents in SU(3) limit of IBM are dependent on the d boson number nd.It is supposed that the coefficient of L L term is the linear function of nd and this problem is solved by perturbation method.The degeneracies of the β and γ bands are solved and the centrifugal effect can be demonstrated.
The variances and mean values of the charge distributions in the dissipative heavy-ion collisions of mass asymmetry system have been calculated by use of the dissipative dynamics equation coupling with the master equation.There is a nice agreement between experimental values and calculated results.
The recent experimental data from TASSO and HRS collaborations for multiparticle production in high e+e－ annihilation is analysed in a cylindrical bag model.It is shown that the observed approximate KNO scaling can be explained in terms of bag parameter B,which determines the hadronization probability densities proportional to the square of the materialization energy.
Sources of 235Th were prepared by 14MeV neutron irradiation of Uranium and radiochemical separation.The β-spectra and γ-spectra were measured.The endpoint energy for 235Th β-decay was obtained to be 1.44±0.04MeV.Thus QB of 235Th was determined to be 1.47±0.07MeV.
An improved approach for regularizing ill-defined sum is presented,and the conformal anomaly in strings is discussed.
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