1988 Vol. 12, No. 6
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A method is described for measuring the beta spectrum from tritium decay in order to determine the electron-antineutrino rest mass.This method includes an electrostatic spherical grid retarding spectrometer with a post focusing system.The resultant energy resolution will be better than 5eV and a maximum luminosity of 0.26cm2 is expected.
In this paper a vertical beam position monitor with split ionization chamber for synchrotron radiation is described.It can be used to detect vertical beam position and relative total intensity at the same time without obstructing the beam.The conventional X-ray experimental results show that its principle is reliable,its strueture is simple and its performance is stable.
Using an Approximate energy conservation method,a Monte-Carlo generator which produces exclusive processes of Chou-Yang geometrical model is constructed.Various comparisons with experimental data have been done conveniently with the help of this generator,the results lead to positive support of the model.In principle the method used is applicable to any other model with given inclusive momenteum distributions.
Vacuum solutions of Dirac's equations in a R-W nuiverse.The exact solution n=n/a for m=0 and the solution n=m+n/a for m≠0 are shown to be generalized results of the an earlier work.These solutions can be interpreted as conformal vacuum or adiabatic vacuum.
We discuss in detail the combination rule of quarks controled by the nearest correlation in rapidity.The average yields of mesons,baryons and the multiplicity distribution produced by stochastic accumulation of N pairs of quarks have been given.Using the relationship between the average yields of quarks-pair and energy,which is in fact universal,we calculate the observed yields of meson,baryon and the multiplicity distribution in e+e－ annihilation.The comparisons among our prediction,the experiment data and the negative binormial distribution are given.
The behavior of the π-meson distribution amplitude is discussed through a phenomenological analysis of some exclusive processes in QCD sum rule.Fπ(Q2) and Br(χ→2π) are calculated by using a trial distribution amplitude.The result of Fπ(Q2) is compatible with experimental data,Br(χ→2π) is of the same order as experimental data.
In this paper we introduce the annihilation terms decribing transitions qiqi→qjqj and qiqi→(gg) and consider the SU(3) breaking effect for these terms.We discuss the mixing mechanism of η,η′and ι and obtain the quark and gluon content of η,η′and ι.At the sametime we introduce EPCAC (Extended Partially Conserved Axial-vector Current) hypothesis and examine η,η′and ι decays in two photons.We calculate yet the ratio R1=Γ(J/ψ→γη′)/Γ(J/ψ→γη) and R2=Γ(J/ψ→γη′)/Γ(J/ψ→γι) and point out the experimental restriction for the pure glueball mass.
Heavy mesons are studied with the Relativistic two body equation.Mass spectrum and the leptonic decay widths of heavy mesons are calculated for potentials of power and logarithmic type.
This paper discussed the conformal transformation between the Witten's string field interacting picture and other pictures.Two kinds of different interacting pictures and explicit forms of their vertex operators are given.One of them can not relate to witten's picture in conformal transformation but another can.
Owing to the change of the path-integral measure for fermion fields under chiral transformation,an additional term (we called it the chiral anomalous term) is added to the action of generating functional of the pure gauge fields theories on coset space of Abelian chiral group.The path-integral quantization of this theory is realized and the invariance of the generating functional under B.R.S. transformation is restored with the aid of the chiral anomalous term.By using the functional derivative technique,the Ward identities are also deduced,which are quite consistent with the classical CVC and PCAC equations.
We consider the transformation properties of the system with non-invariance action integral under the infinite continuous group which yields the generalized Noether's identities,from which we can deduce the strong and weak conservation laws of this system and in connection with the conserved PBRS charge of the massive Yang-Mills field are given which deffers from the conserved BRS charge.The Dirac's constraint of the variance system are discussed.
We show that two models in explaining the EMC effect give different results and predictions,though both of them are using certain ways to take into account the binding effect.The first can explain the bulk of the EMC effect only,whereas the second can explain,besides the bulk of the EMC effect,the detailed features of the SLAC data and the discrepancies between the EMC data and the SLAC data.The two models also give dfferent predictions of the ratio RA=σL/σT in deep inelastic lepton nucleus scattering.It seems that the available data favour the second model.
Some probiems relating to the beam dynamics computation of the transverse motion for the 35MeV Beijing Proton Linac are discussed.The computation results are used in the beam test of the linac and whereby the suitability and relibility of the computation are proved.These computations are useful in guiding the beam test of the linac.
The real relativistic microscopic optical potentials for 16O and 40Ca have been calculated self-consistently in the framework of the Walecka model and the non-linear σ model.To compare with nonrelativistic optical potentials,the Schrodinger equivalent potentials are obtained.The differential cross sections and polarizations for the nucleon-nucleus elastic scatterings also have been calculated.It is found that the optical potentials obtained in the framework of the non-linear σ model are better than that in the Walecka model.
The seniority v-structure and the K-structure of the CSM wave function for odd particlenumber system are analysed.For not too high ω (hω≤0.5MeV) configurations with v=1,3,5 are dominant for the low-lying bands,while those with v≥7 are negligibly small.Also the K-structure of the low-lying bands become very complicated.Calculation shows that the blocking effect is very important for the low-lying bands in low-ω region.
The characteristics of nuclear reactions with giant resonances as door-way states is discussed.The Feshbach-Kerman-Koonin theory is modified properly and used to derive the cross section formula of multi-step compound nuclear reactions with resonances as door-way states.In parameterization,the extended exciton model is obtained.As examples,the photo-nuclear reactions is described in such an extended exciton model.
A microscopic calculation of 15O-15N,17F-17O Coulomb displacement energies is performed from the Paris potential and electric magnetic interactions using Green's function method.The contribution of charge-symmetry-breaking property of the G matrix is relatively important.It is about twice as large as that of the usual phenomenal charge-symmetry-breaking potential in the nuclear forces.
The excitation function for α transfer reaction 28Si(16O,
The experimental data of the capture and complete fusion cross section for 35Cl,40,43Ca+238U system are fitted by using the Extrapush Model.In consideration of the competition between the fission and neutron evaporation,the excitation functions of the capture cross section,complete fusion cross section and neutron evaporation cross section have been calculated for Ar+233,235,238U system.
The variances of the mass distribution,also neutron-protion correlation function for the collision systems of single closed shell nuclei 144m+144m and no closed shell nuclei 154Sm+154Sm have been calculated by use of the master equation coupling with dissipative dynamics equation under including shell corrections.All of values are systematical difference between two collision systems.There is a nice agreement between experimental values and calculating results.It is shown that the shell effects are important for the variances of mass disstribution and charge distribution for low bobardment energies.
A mean-field theory is used to study the chiral phase transition at finite temperature.The critical temperature and the phase diagram are obtained.
The field theory limit of superstring theories in ten dimensions suggests a compactification on the Calabi-Yau manifolds.The authors present a cosmological inflation solution of this scenario to which a matter term is added.
Through a covariant regularization of the chiral fermion current,we derive the covariant fermion current divergence anomaly as well as the covariant Gauss law commutator anomaly of the chiral gauge theory in the canonichl formalism.
We propose a model for the calculation of the inclusive eta production reaction induced by pion.The comparison between our theory and the experiments shows that the η particle emission in π-A collisions is a process of surface production.
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