Tan Zhen-Qiang

Spin effects and N̄N annihilation effects in elastic antiproton-nucleus scattering

The differential cross section, the polarisation and the spin-rotation parameter in elastic scattering of 180 MeV antiprotons by 12C and 16O are calculated by means of Glaubers multiple scattering theory and Pauli-correlated wavefunction. The effects of N(mean)N annihilation are studied by using a phenomenological N(mean)N annihilation potential within this framework. The results indicate that spin effects are negligible at small angles but that at large angles spin effects improve the elastic angular distribution, and that the N(mean)N annihilation part of the amplitudes contributes significantly to the observables.

NN annihilation effect in elastic\(\bar p\)-nucleus scattering

SummaryThe effect ofNN annihilation on antiproton-nucleus scattering has been studied by use of phenomenologicalNN annihilation potential. The results indicate that at small angle the effect makes no difference but for large angles it plays an important role in solving the discrepancies between theory and existing data available.RiassuntoSi è studiato l’effetto dell’annichilazione diNN sullo scattering tra antiprotone-nucleo con l’uso del potenziale di annichilazione diNN fenomenologica. I risultati indicano che ad un angolo ridotto l’effetto non fa alcuna differenza, ma per angoli ampi gioca un ruolo importante nel risolvere le discrepanze tra la teoria e i dati disponibili esistenti.РезюмеИспользуя феноменологический потенциалNN аннигиляции, исследуется влияниеNN аннигиляции на рассеяния антипротонов на ядрах. Полученный результат показывает, что при малых углах эффект пренебрежимо мал, а при больших углах играет важную роль в обьяснении расхождений между теорией и имеющимися экспериментальными данными.

An integral formula for calculating the Glauber multiple scattering amplitude of composite particles

An integral formula is derived for calculating the complete expansion of the Glauber amplitude for multiple scattering when the density function is of the form, rho (r)= Sigma c>or=0(A2cr2c)exp(- alpha 2r2).

Wormhole in the Einstein theory

SummaryIn this paper, we discuss the wormhole model with the axion charge in the Einstein theory with the cosmological constant, and deduce the corresponding wormhole equation. By solving this equation, we give a wormhole which connects the corresponding points in two Euclidean-de Sitter space-times.

Wormholes and the Fermi field

Abstract In this paper, we discuss the wormhole model with the coupled Fermi field, deduce the corresponding equations and give an analytical solution of them.

Proton-oxygen elastic scattering and spin effects at Tp=200 MeV in the four α-particle model

By using a phenomenological amplitude fitted with p-4He elastic scattering data, p-16O elastic scattering is studied via a theoretically deduced optical potential based on the alpha -particle model for 16O. The differential cross sections, polarisations and spin-rotation parameters are calculated at Tp=200 MeV. The results are compared with the experimental data and satisfactory agreement is obtained.

J/ψ and φ Electro-production in Pomeron Exchange Model

Based on Pomeron exchange model, J/ψ and φ production in electro-proton interaction are investigated with both linear and non-linear Pomeron trajectory. The experimental differential cross sections measured as a function of the kinematic variable Q2,W and t are reproduced successfully in the model. Our conclusions are that the Pomeron exchange model is a successful description of J/ψ and φ electro-productions on the proton, and that the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory.

Antiproton-Nucleus Interaction and Coulomb Effect at High Energies

The Coulomb effect in high energy antiproton-nucleus elastic and inelastic scattering from 12C and 16O is studied in the framework of Glauber multiple scattering theory for five kinetic energies ranged from 0.23 to 1.83 GeV. A microscopic shell-model nuclear wave functions, Woods–Saxon single-particle wave functions, and experimental N amplitudes are used in the calculations. The results show that the Coulomb effect is of paramount importance for filling up the dips of differential cross sections. We claim that the present result for inelastic scattering of antiproton-12C is sufficiently reliable to be a guide for measurements in the very near future. We also believe that antiproton nucleus elastic and inelastic scattering may produce new information on both the nuclear structure and the antinucleon-nucleon interaction, in particular the -neutron interaction.

Vector Meson electro-production in Pomeron exchange model

Based on Pomeron exchange model, elastic production of vector meson in electro-proton interaction is investigated with both linear and non-linear Pomeron trajectory. A numerical calculation for J/psi production is performed. The effect of the energy scale so and photon virtuality Q(2) on differential cross section are also predicted. A good agreement with experimental data is obtained. Our conclusions are that the Pomeron exchange model is a successful description of J/psi electro-production, the dependence of the differential cross sections on Q2 is negligible, the linear trajectory is a good approximation to non-linearity of the Pomeron trajectory, and the value of the energy scale parameter so is dependent on the momentum transfer, namely its effect is moderate at low momentum transfer but it causes no difference at high momentum transfer vertical bar t vertical bar >= 1.25 GeV2.

Antiproton-carbon inelastic scattering and\(\overline N N\) annihilation effectsannihilation effects

SummaryThe differential cross-sections of inelastic scattering for antiprotons by12C at incident momentumPlab=600 MeV/c are calculated on the basis of Glaubers multiple scattering theory and the distorted wave impulse approximation and by use of the transition densities obtained from fitting to the electron scattering data and the elementary two-body amplitudes.