Microscopic analysis of antiproton-nucleus elastic scattering

Elastic antiproton-nucleus scattering is analysed with a microscopic optical model potential obtained by convoluting an effective interaction with target densities. Local, energy- and density-dependent complex effective interactions are constructed from reaction matrices generated with the Dover-Richard and Paris potentials. Effects of nuclear medium correction on the final results are examined. Comparison is made between the calculated results and the experimental data from LEAR which include the first polarization data as well as differential cross sections.     

Microscopic calculation of the repulsive core in the elastic nucleon-nucleon scattering

The resonating group method is used to study the effective potential between two nucleons, due to the confining potential between quarks taken together with the Pauli principle for quarks. The potential used has harmonic form, unitary spin factor λ(1)·λ(2), and both ordinary and spin-spin components. Its parameters are determined by appeal to experimental data, and phase shifts are calculated for the¹ S ₀ and³ S ₁ states of the nuncleon-nucleon (NN) system. The results indicate that the repulsive core in theNN potential may arise from quark antisymmetrization required if nucleons are composed of quarks.     

The antiproton-nucleus elastic scattering and the alpha-cluster model with dispersion

The elastic scattering differential cross sections of intermediate energy antiprotons on¹²C and¹⁶O nuclei and the elastic scattering polarization observables of antiprotons on these nuclei have been calculated on the basis of theα-cluster model with dispersion and multiple diffraction theory. The results of these calculations are compared with the experimental data.     

An exploratory study of antiproton-nucleus scattering

An exploratory study of¯p-nucleus scattering at low and medium energies (<200 MeV) is presented using optical potentials which are representative of those either derived from¯p-atomic data or calculated theoretically. The elastic differential cross sections are sensitive to the potential characteristics. Some indicative cases of inelastic scattering were also examined. Reaction cross sections are discussed and compared to recent measurements.     

Semi-classical approach to antiproton-nucleus scattering

The similarities and differences between antiproton-nucleus scattering and heavyion-nucleus scattering are examined. It is found that the one-turning point approach viz Wentzel, Kramers and Brillouin (WKB) approximation can be applied to the analysis of antiproton-nucleus scattering. Using this approximation, a closed form expression for the nuclear phase shift is deduced from the corresponding expression for the heavy-ion scattering phase shift derived by Shastry and the method is illustrated by carrying out the cross-section calculation of atE _lab = 46·8 MeV.     

Microscopic potentials for polarized triton elastic scattering

The double folding model is used to calculate real central and spin-orbit potentials for triton elastic scattering. These potentials are used to fit cross sections and analysing powers at 17 MeV for targets ranging from ²⁶Mg to ²⁰⁸Pb. For most targets the data are described as well as with phenomenological potentials. The real central potential can be used without any substantial renormalisation, but the spin-orbit potential needs to be increased in strength by a factor between 2 and 6. Comparisons are made with phenomenological studies of triton and ³He elastic scattering and with similar microscopic studies of ³He scattering.     

Variational calculation of elastic nucleon-deuteron scattering

A previously developed variational principle for three-body scattering is applied to elastic nucleon-deuteron scattering. Separable S-wave potentials are used for both the singlet and triplet channels. The scattering amplitudes obtained agree with previous calculations and are accurate to four places. The three-body wave functions, which are needed for perturbation calculations, are also well converged.     

Intermediate annihilation states in antiproton-nucleus scattering

We study the annihilations on nuclei paying special attention to the role of unitarity in these processes. Analysing the intermediate states, it is shown that the annihilation cross section is much larger than the difference $\text{p}\text{?}\text{A ?}\text{p}\text{A}$ and for heavy nuclei is even larger than the non-annihilation cross section. The singular way in which unitarity works in annihilations can be used to test several models of particle-nucleus interactions.     

Microscopic approach to the antiproton-nucleus optical potential

By using the self-energy of an antiproton evaluated in nuclear matter, the antiproton effective interaction with a bound nucleon is derived and is found to have a drastic density dependence. The p?-nucleus optical potential constructed by folding the effective interaction well reproduces experimental data on the p?-nucleus absorption cross section as well as on the complex level shift of p?-atoms. In addition, it is pointed out that the strong spin-orbit interaction spreads each doublet and considerably affects the lower complex level shift.     

Microscopic spin-orbit potentials for polarized 3He elastic scattering

The M3Y double folding model is used to calculate real central and spin-orbit potentials for ³He elastic scattering. These potentials are used to fit cross sections and analysing powers at 33 MeV for targets ranging from ¹⁶O to ⁵⁸Ni. The real central potential needs a normalization factor of about 0.85, but no change in the strength of the spin-orbit potential is necessary. Comparison is made with phenomenological and other microscopic studies of ³He elastic scattering.     

Absorption and refraction phenomena in proton- and antiproton-nucleus scattering

The experimental data on the 180 MeV proton and 50, 180 MeV antiproton scattering by the nuclei¹²C,⁴⁰Ca and²⁰⁸Pb have been analysed on the basis of the phenomenological diffraction theory. The optical properties of the nuclei with regards to the incident protons and antiprotons are investigated. Various limiting cases of the proton- and antiproton-nucleus scattering are considered. The contribution of the Coulomb and the spin-orbit interactions to the differential cross sections of these processes has been also analysed.The authors are indebted to D.M. Skrypnik for assistance in preparing the English version of this paper.     

An analytic distorted wave approximation for antiproton-nucleus scattering

The differential elastic scattering cross-sections of intermediate energy antiprotons from Carbon and Aluminum have been analysed to determine parameter values of analytic representations of the optical model, distorted waves; such representations being convenient for use in analyses of non elastic reaction data.     

超冷钠原子弹性散射特性的精确计算

基于精确的原子之间相互作用势,系统研究了钠原子在超冷温度下的弹性散射特性,精确计算了钠原子间碰撞时的s波散射长度、有效力程、p波散射长度以及束缚态数目等散射参数.超冷温度下单重态和三重态原子间的弹性散射截面主要为s波贡献,随着碰撞能量的增加散射截面有丰富的形状共振出现,计算发现单重态和三重态散射截面分别存在显著的f波和i波形状共振.应用简并内态近似方法获得了超精细态相互作用时的s波散射长度,所得结果与精确值比较符合.     

A two channel calculation for elastic α-α scattering

Starting with a realistic nucleon-nucleon soft core potential the α-α phase shifts were calculated in the refined cluster model framework. It is shown that the inclusion of inelastic α^*-α channels yields considerable improvement in the results. Below inelastic thresholds, calculated and experimental values are in quantitative agreement.     

Microscopic calculation of the inclusive electron scattering structure function in 16O

We calculate the charge form factor and the longitudinal structure function for 16O and compare with the available experimental data, up to a momentum transfer of 4 fm(-1). The ground-state correlations are generated using the coupled-cluster [ exp(S)] method, together with the realistic v18 NN interaction and the Urbana IX three-nucleon interaction. Center-of-mass corrections are dealt with by adding a center-of-mass Hamiltonian to the usual internal Hamiltonian, and by means of a many-body expansion for the computation of the observables measured in the center-of-mass system.