1992 Vol. 16, No. 2
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Best fitting the pseudorapidity distribution data from ISR and SppS in inelastic process,assuming that the multiplicity distribution of secondary particles approximately follows the KNO scaling and transverse momentum approximately follows f(pt)∝pt·e-apt (where a is a constant),we contructed a hadron-hadron nuclear interaction parametrization model which is suitable to analyses of emulsion chamber experiment.
This paper describes the radiation source and its characteristics of the Synchrotron Radiation Experimental Hall of BEPC,the radiation measuring method and measured results.It has been found that the radiation dose level of the Synchrotron Radiation Experimental Halls is closely correlative with the relative location of the Experimental Halls to the injection points of the electron and positron beams,the thicknesses of the shielding walls,the times and efficiencies of the beam injections.
We calculate the W-boson electric dipole moment in the Weinberg-Higgs model in which the Cp violation is mediated by charged Higgs boson exchange and compare our results with other works.
A new formula for the hyperfine mass splitting of mesons is established by using energy-dependent spin-spin potential between quark and antiquark.Data analysis indicates that this formula is capable of describing hyperfine mass splitting of mesons in ground-state or excited-state with isospin zero or nonzero.
Relativistic microscopic optical potential of nucleon-nucleus is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation.The complex effective mass of a nucleon is determined by a fit to 200MeV p-40Ca scattering data.The relativistic microscopic optical potentials with this effective mass are obtained from RBBG for p-16O,40Ca,90Zr and 208Pb scattering in energy range from 160 to 180MeV.The microscopic optical potential is used to study the proton-40Ca scattering problem at 200MeV.The results,such as defferential cross section,analyzing power and spin rotation function are compared with those calculated from phenomenological relativistic optical potential.
By means of the imaginary-time Green's function method,the temperature dependences of the η-meson and nucleon interaction coupling constant and one one η-meson exchange potential are discussed.We find that when temperature increases to 215MeV,the coupling constant approaches to zero and the one η-meson exchange potential of nucleon-nucleon disappears.
If the antiproton optical potential is inclusive of the spin orbit interaction term,the A(p,p)A* inelastic scattering not only can excited the normal parity states,but also can excited the abnormal parity states.There are also induced the polarization Pf(θ) at the inelastic scattering.In the framework of DWIA,we derived the inelastic scattering cross section (dσ/dΩ)f,i,and polarization Pf(θ),and calculated the (dσ/dΩ)f,i, and Pf(θ) for 12C(p,p)12C* with 2+,3－ and 1+ states at antiproton energies of 46.8 and 179.7MeV.They fited experiment data quite well.Due to the abnormal partity states in the inelastic process have been measured,the spin orbit term can not be neglect.
Contribution from the breakup-fusion mechanism to continuum spectra of nuclear reaction is introduced.In this mechanism a two-step process is considered in which the projectile breaks up to two pieces in the field of target,and fusion of one piece with the target is followed.A method of finite range calculation is presented.The comparison of theoretical calculation with experimental data is shown for reactions on light and heavy targets bombarded by α-projectile.The results show that the breakup-fusion mechanism mainly contributes to continuum spectra.
Activation techniques have been used to measure the cross-section for 58Ni(n,p),60Ni(n,p) and 62Ni(n,α) reactions in the neutron energy range 13.6—17.8MeV.The uncertainty of measured data has been aculated from 3%—7%.The covariance matrixes for measurement error are calculated.Evaluations for 58Ni(n,p),60Ni(n,p),62Ni(n,α) and 54Fe(n,p) crpss-section are made.
The differntial elastic scattering cross sections of Zr for 14.2MeV neutrons are measured by the associated particle time-flight method at angles from 10° to 140°.The corrections for neutron flux attenuation,multiple scattering and finite geometry are performed by using Monte-Carlo method.The experimental results are compared with the available lata from other work and the theoretical calculation.
By employing the 1/N expansion technique,the analytical expressions of the reduced E4 matrix elements are derived for deformed nuclei.The results of the strengths of E4 transitions show that the inclusion of the rotational effects in E4 transition improves greatly the agreement between the theory and the experimental data.
A mass formula with deformation and shell corrections for a few free parameters was described.By means of the formula the calculations of 1440 nuclear masses and 1250 two neutron separation energies s2n in the region of 28≤Z≤81 were performed.The root-mean-square deviations are respectively 1.01MeV for nuclear masses and 0.57MeV for s2n.The results of the theory could also reproduce the characters of the closure shell,the subshell and the deformation of the nuclei.
Some properties about the effective boson charges are discussed in term of the neutron-proton interacting boson model.The effective boson charges of some U(5)-like and O(6)-like nuclei are extracted from the experimental data of electromagnetic transition probabilies.With the calculated effective boson charges the electromagnetic transition probabilities of the mixed states in the nuclei are calculated,too.It shows that the effective boson charges both of neutron and proton have something of screening effect.
Degeneracy of parity even and odd electron solutions of the free Dirac equation may cause uncertainties in first order calculation of the perturbatiove energy.Choosing the even parity solution to start perturbation is though direct,not theoretically well supported.The arbitrariness in choosing lowest order electron wave functions causes nucertainties in the Foldy-Wouthuysen transformations and reduction of the Pauli equation from the Dirac equation.
In order to convenience for the data analysis of BES some new relations which can be used to search for the 1－+ exotic state in J/ψ→ωX,X→KKπ have been obtained.How to search for the 1－+ exotic state in the three-step two-body hadronic decay process J/ψ→ωX,X→KK*,K*→Kπ is also discussed.
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