Spin effects in elastic antiproton nucleus scattering

Elastic scattering of 180 MeV antiprotons by several closed-shell nuclei are analyzed using Glauber's multiple scattering theory. Spin observables in elastic scattering are obtained within this framework. The sensitivity of the polarizations to the spin-flip amplitudes are discussed in terms of the¯NN potential models used for the calculations. Spineffects in angular distribution are found to be small.     

水下弹性圆柱的共振散射

当声波频率与水下弹性圆柱的某一模式的共振频率相符时,圆柱受声波激励产生的共振振动向周围介质辐射的声波最强。国内、外研究表明,对一般的金属圆柱而言(其弹性纵波与切变波速度大于水中声速),在与入射波方向相反的方向上,由于这种辐射声波与圆柱表面的几何反射波位相相反,因此两者干涉的结果形成了在共振频率上出现反向散射声振辐的极小值。本文揭示了一种新的情况,即对于弹性切变波波速小于水中声速的一种材料做成的圆柱体,无论是理论计算和实验测量,均表明在共振频率上出现反向散射振幅的极大值。     

Proton-proton elastic scattering via the Trojan horse method

We address a successful indirect technique, the Trojan horse method, which allows one to measure the bare nucleus cross section for rearrangement reactions down to astrophysical energies. In particular, we consider here the application of the method to the p-p elastic scattering. This represents an important test of the main feature of the method, namely the suppression of Coulomb effects in the entrance channel due to off-energy-shell effects. In contrast to the on-energy-shell case, the extracted p-p cross section does not exhibit the Coulomb-nuclear interference minimum, as predicted by the half-off-energy shell calculations. This hypothesis is strengthened by the agreement between the Trojan horse p-p data and the calculated on-energy-shell n-n, n-p and nuclear p-p cross sections.     

Backward elastic pd scattering in the resonance energy region

The cross section for backward elastic pd scattering in the proton kinetic energy interval from 0.4 to 1.0 GeV is calculated from a double-triangle diagram with intermediate Δ(1232) excitation. Different approximations for the loop integrals are discussed. The predicted cross sections reproduce quite well the enhancement observed in the experimental data at about 600 MeV.     

可分离变量的水下弹性体的纯弹性共振散射

理论上,共振散射谱的提取通过纯弹性散射函数来实现,它定义为总的散射函数和合适的背景项之差。本文导出具有可分离变量的水下弹性体的纯弹性散射函数的简单而明显的表示式。它取决于模态的机械阻抗和声阻抗,除了一个只依赖于形状的相位因子外。用新公式分析分波共振谱发现两类不同特性的共振：弹性波共振和流体波共振。前者主要取决于物体的弹性,流体负荷的作用是第二位的。后者紧密联系于流体负荷,当流体负荷消失时它也消失。这就允许我们对单个共振正确地分类。最后,计及流体波共振极点,应用奇异点展开法对传统的共振散射公式进行了修正。     

Pure elastic resonance scattering for submerged elastic objects with separable geometries

I.IntroductionTheResonanceScatteringTheory(RST)wasdevelopedasabasicmethodtoanalyzesoundscatteringfromelasticobjectsimmersedinwater.Itwasusedtocylindricalandspher-icalgeometries,includingsolidandshellobjects.TheRSTinvestigatesmainlytheresonancespectrumofscatteredwavefromanelasticobjectexcitedbytheincidentwave.Theresonallcespectrum,namedthe'AcousticSpectroscoPy',reflectsmaterialcharactersoftheobjectsandcanbeusedtoidentifythetarget.Theresonallcespectraareisolatedbysubtractingfromthescattere…     

Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of 150 - 170^° at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years.     

Probing proton halo of the exotic nucleus28S by elastic electron scattering

Science China Physics, Mechanics & Astronomy - Elastic electron scattering on the exotic light nucleus28S is investigated in the plane wave Born approximation. The variation of the squared form...     

Probing proton halo of the exotic nucleus ~(28)S by elastic electron scattering

~~Probing proton halo of the exotic nucleus ~(28)S by elastic electron scattering~~     

Identification of cavity fillers in elastic solids using the resonance scattering theory

Elastic waves incident on and scattered by fluid-filled (spherical) cavities in solids are usually described by summed scattering amplitudes. These summed amplitudes, when analysed one partial wave at a time, are seen to consist of two interfering contributions. One is a smooth background corresponding to scattering from an empty cavity, and the other is a superimposed set of resonance ‘spikes’ (lines with narrow width) of the filler fluid. We show in this paper how these modal resonances and their widths can be used to identify the material composition of the filler fluid in a way that resembles the spectroscopic methods used to identify chemical elements by means of their optical spectra.     

Proton-proton elastic scattering and nucleon resonance production at high energies

Angular distributions of proton-proton elastic scattering have been measured for incident beam momenta of 10.0, 12.0, 14.2 and 24.0 GeV/c over a range of lab scattering angles from 12 to 152 mrad. This is equivalent to a range of four-momentum transfer squared from about 0.1 to 6.7 GeV² at the highest momentum. Nucleon resonance production in the two-body reaction p + p → p + X has been studied at 24.0 GeV/c incident momentum from 13.5 to 112 mrad by measuring the proton momentum spectra from the elastic peak down to a momentum corresponding to a missing mass of about 2.6 GeV. The new data are compared with previous results and theoretical models.     

Simulation and analysis of 13N+p elastic resonance scattering

The ^13 N＋p elastic resonance scattering has been studied at the secondary radioactive beam facility of CIAE in inverse kinematics via a thick-target method. The excitation function for the ^13N（p,p） scattering was obtained in the energy interval of Ecru ≈0.5-3.2 MeV with a ^13 N secondary beam of （47.8±1.5） MeV. Careful analysis of the secondary beam components and extensive Monte-Carlo simulations enable the resolution of the experimental proton spectra. The resonance parameters for five low-lying levels in ^14 O were deduced by Rmatrix fitting calculations with MULTI7 and SAMMY-M6-BETA. The present results show general agreement with those from a recent similar work, and thus confirm the observation of a new 0^- level at 5.7 MeV in 140 with an improved width of 400（45） keV.     

Simulation and analysis of 13N+p elastic resonance scattering

The 13N+p elastic resonance scattering has been studied at the secondary radioactive beam facility of CIAE in inverse kinematics via a thick-target method. The excitation function for the 13N(p,p) scattering was obtained in the energy interval of Ecm ≈0.5--3.2 MeV with a 13N secondary beam of (47.8±1.5) MeV. Carefulanalysis of the secondary beam components and extensive Monte-Carlo simulations enable the resolution of the experimental proton spectra. The resonance parameters for five low-lying levels in 140 were deduced by R- matrix fitting calculations with MULTI7 and SAMMY-M6-BETA. The present results show general agreement with those from a recent similar work, and thus confirm the observation of a new 0- level at 5.7 MeV in 14O with an improved width of 400(45) keV.     

Investigation of condensed matter by means of elastic thermal-neutron scattering

The application of elastic thermal-neutron scattering in investigations of condensed matter that were performed at the Institute for Theoretical and Experimental Physics is described. An account of diffraction studies with weakly absorbing crystals, including studies of the anomalous-absorption effect and coherent effects in diffuse scattering, is given. Particular attention is given to exposing the method of multiple small-angle neutron scattering (MSANS). It is shown how information about matter inhomogeneities can be obtained by this method on the basis of Molière’s theory. Prospects of the development of this method are outlined, and MSANS theory is formulated for a high concentration of matter inhomogeneities.     

Evidence for resonance and absorption effects in positron-atom differential elastic scattering

This review focuses on recent positron-atom elastic differential cross section (DCS) measurements which reveal evidence that interference effects may be occurring between the elastic and inelastic scattering channels. These effects appear as (1) absorption effects which are observable in relative elastic DCSs by the washing out of structure in the DCS versus angle as the positron energy is increased above the positronium formation threshold, and (2) a new type of resonance-like structures at intermediate energies (well above the normal inelastic thresholds) that have been observed in absolute elastic DCS measurements when plotted at a fixed scattering angle versus energy. A discussion is provided of possibly relevant information on positron-atom scattering that also indicates that coupling is occurring between various scattering channels.     

Sensitivity of cross sections for elastic nucleus-nucleus scattering to halo nucleus density distributions

In order to clear up the sensitivity of the nucleus-nucleus scattering to the nuclear matter distributions in exotic halo nuclei, we have calculated differential cross sections for elastic scattering of the ⁶He and ¹¹Li nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon with different assumed nuclear density distributions in ⁶He and ¹¹Li.     

Double folding model analysis of elastic scattering of halo nucleus 11Be from 64Zn

Calculations of elastic scattering cross-sections for ^9,10,11Be + ⁶⁴Zn at near-Coulomb barrier energy have been performed using a potential obtained from the double folding model and are compared with the experiment. In the framework of the double folding model, the nuclear matter densities of ^9,10,11Be projectiles and a ⁶⁴Zn target are folded with the complex energy-dependent effective M3Y interaction. The angular distributions of the differential cross-section for ^9,10Be scattering from ⁶⁴Zn at E _c.m≈ 24.5 MeV agree remarkably well with the data, while in case of ¹¹Be, calculations show a Coulomb–nuclear interference peak which is not observed in the data.     

Mechanism of elastic and inelastic proton scattering on a 15C nucleus in diffraction theory

The amplitudes for elastic and inelastic proton scattering on the neutron-rich nucleus ¹⁵C (to its J ^?? = 5/2⁺ level in the latter case) in inverse kinematics were calculated within Glauber diffraction theory. First- and second-order terms were taken into account in the multiple-scattering operator. The ¹⁵C wave function in the multiparticle shell model was used. This made it possible to calculate not only respective differential cross sections but also the contribution of proton scattering on nucleons occurring in different shells. The differential cross sections for elastic and inelastic scattering were calculated at the energies of 0.2, 0.6, and 1 GeV per nucleon.