Correlation effects in electron-ion collisions in a strong laser field

We examine elastic and inelastic scattering of electrons by ions in intense laser light. A method of numerical investigation of the scattering characteristics based on regularizing the Coulomb singularity is proposed. We show that over a broad range of parameter values the transport scattering cross section is weakly dependent on the intensity of the high-frequency field. We detect a significant modification of the dependence of the effective inelastic scattering cross section. We also show that the energy exchange with the field is determined by a fairly small group of electrons, called the representative electrons. Finally, we propose a qualitative model that explains our results by the fact that the leading contribution is provided by inelastic collisions of electrons with relatively small impact parameters traversing the region important for the interaction at large angles. Zh. éksp. Teor. Fiz. 115, 463–478 (February 1999)     

Semi-inclusive deep inelastic lepton scattering in a pion cloud model

In this note we explore the consequences of the pion cloud model for semi-inclusive deep inelastic lepton scattering. We argue that by scattering on a few-nucleon target, the detection of the recoiling target would provide a valuable test of the meson cloud model. We estimate the semi-inclusive cross section for deep inelastic lepton scattering on a³He target, as function of Bjorkenx and target recoil momentum.     

Inelastic shadowing effects in multiple scattering

The projectile-nucleon scattering amplitudes used as input into multiple scattering theories of projectile-nucleus scattering naturally include the effects of coupling to inelastic (i.e., production) channels. We employ a multichannel separable potential to describe the projectile-nucleon interaction and show that within the fixed nucleon framework we can obtain the nuclear elastic scattering amplitude. This includes terms outside the conventional formalisms, corresponding to intermediate propagation in the inelastic channels both above and below inelastic threshold. We refer to this as inelastic shadowing. In a two-channel approximation, we show that knowledge of the projectile-nucleon elastic scattering phase shifts plus specification of the inelastic threshold energy are sufficient to determine the off-shell coupled-channel transition matrix, implying that the nuclear amplitude can be calculated within this model without any detailed information about the inelastic channels. We study this solution quantitatively for some model problems and for pion scattering, with the general result that inelastic shadowing can be significant whenever the elementary interaction has important channel coupling. For pion scattering in the energy regime characterized by strongly absorptive resonances, we find, for example, that the effect of inelastic shadowing is much more important than that due to two-nucleon correlations.     

Combined nuclear-molecular resonance inelastic scattering of x rays

We report on theoretical and experimental studies of nuclear inelastic scattering in a molecular crystal, whose atoms experience both molecular and lattice vibrations. In this case scattering proceeds as combined nuclear-molecular resonance inelastic scattering. The lattice vibrations give rise to inelastic scattering around the molecular resonances with an energy dependence identical to that around the nuclear resonance. The incoherent nature of the scattering in the molecular resonances results in a proper balance of elastic and inelastic components, which has important implications for studies of heterogeneous systems.     

Simultaneous energy analysis in a large angular range: A novel neutron spectrometer,its resolution and applications

A new type of crystal spectrometer for elastic and inelastic neutron scattering has been set up by modifying an existing flat-cone diffractormeter at the BER II-reactor in Berlin (West). The main difference to conventional triple axis spectrometers is the analyser part. It consists of large crystal plates which reflect the neutrons out of the horizontal plane into a curved multicounter. This allows simultaneous measurements in a large and continuous range of scattering angles for a constant energy transfer. The resolution function has been calculated and compared with experimental results. There is the possibility to focus acoustical phonons. We present applications together with experimental results such as quasielastic diffuse scattering in orientationally disordered crystals and inelastic scattering due to acoustical phonons. In combination with the flat-cone technique all elastic and inelastic scattering events of a single crystal can be collected in a systematic and efficient way.in collaboration with the Hahn-Meitner Institut, Berlin (West)     

The need for a state dependent interaction in proton inelastic scattering from 24Mg

The calculated angular distributions for proton elastic and inelastic scattering can be greatly improved by using an imaginary potential which depends upon the nuclear state. We demonstrate that this is just the effect expected from the coupling of deuteron channels and the phenomenon therefore provides a signature for multistep processes which is not dependent on detailed calculations. The obvious application to the usual DWBA calculations of inelastic proton scattering is mentioned.     

QCD predictions for polarized deep inelastic scattering accompanied by a forward jet in the low x region of possible HERA measurements

We estimate the cross-section and asymmetry relevant for the production of forward jets in polarized deep inelastic scattering in the region of small values of x which can be probed at possible polarized HERA measurements. The kinematical cuts implemented in our analysis are the same as those which were used in the unpolarized deep inelastic scattering at HERA. The calculations are based on the double ln²(1/x) resummation which controls the polarized deep inelastic scattering for small values of the Bjorken parameter x. We show that this resummation substantially enhances the corresponding cross-section and asymmetry. The predicted value of the asymmetry is found to vary between −0.01 and −0.04 within the small x region which can possibly be probed at polarized HERA measurements.     

库仑程函近似下非弹性散射振幅角分布的广义函数分析

在库仑程函近似框架下,引进实参量(时间扫描参数)积分,将能壳上跃迁矩阵元分为靶的结构因子和弹的扭曲因子,导出了非分波扭曲因子的主项表达式和结构因子的解析表达式,利用广义函数方法分析了电子与类氢离子的非弹性散射角分布.     

Elastic and inelastic diffraction of Mössbauer γ-rays from KCN

Mössbauer γ-ray diffraction was used to discriminate between the elastic and inelastic scattering intensities from the (1 1 1) to (5 5 5) Bragg reflections of a single crystal of KCN. The energy resolution of our experiment was 28 neV. We observe pronounced inelastic peaks at each Bragg point, while the elastic scattering dies out rapidly due to a large Debye-Waller factor. Thus in case of (4 4 4) and (5 5 5) the inelastic scattering is larger in magnitude than the elastic one.     

Momentum-resolved charge excitations in a prototype one-dimensional mott insulator

We report momentum-resolved charge excitations in a one-dimensional (1D) Mott insulator studied using high resolution inelastic x-ray scattering over the entire Brillouin zone for the first time. Excitations at the insulating gap edge are found to be highly dispersive (momentum dependent) compared to excitations observed in two-dimensional Mott insulators. The observed dispersion in 1D cuprates ( SrCuO2 and Sr2CuO3) is consistent with charge excitations involving holons which is unique to spin-1/2 quantum chain systems. These results point to the potential utility of momentum-resolved inelastic x-ray scattering in providing valuable information about electronic structure of strongly correlated insulators.     

Interband transitions and electronic Raman continuum in systems with strong inelastic scattering: Applications to YBa2Cu3O7-δ

We consider a model for the electronic Raman continuum which takes into account strong inelastic scattering and interband transitions. Calculations are based on four-vertex Raman scattering diagrams (Kawabata formalism) within the RPA for Coulomb interaction and the ladder diagram Bethe-Salpeter equation for the vertex. We apply this method to an analysis of the nature of the electronic Raman continuum in the normal state of the high-T _c superconductor YBa₂Cu₃O₇. In numerical calculations we take into account all the self-energy effects and make simulations for vertex corrections assuming that inelastic scattering is due to electron-phonon interaction. Theab-plane polarized continuum contains a large contribution from interband processes and does not depend strongly on temperature and inelastic scattering strength. The in-plane anisotropy is determined by interband transitions rather than by anisotropy of the Fermi surface. The ZZ continuum contains only weak contribution from interband transitions. It can be crudely described within a single band model with inelastic scattering and is strongly dependent on the relaxation rates of inelastic scattering. The nature of the oxygen-deficiency dependence of the Raman spectra is also commented upon.     

Suppression of inelastic collisions between polar molecules with a repulsive shield

We propose and analyze a technique that allows one to suppress inelastic collisions and simultaneously enhance elastic interactions between cold polar molecules. The main idea is to cancel the leading dipole-dipole interaction with a suitable combination of static electric and microwave fields in such a way that the remaining van der Waals-type potential forms a three-dimensional repulsive shield. We analyze the elastic and inelastic scattering cross sections relevant for evaporative cooling of polar molecules and discuss the prospect for the creation of stable crystalline structures.     

Medium corrections in intermediate-energy nucleon-nucleus scattering

Medium corrections in elastic and inelastic nucleon-nucleus scattering are discussed in the framework of Watson's multiple scattering theory. We derive formulae for the effective interactions to be used in the calculation of elastic and inelastic scattering based on a consistent local-density approximation. We show the numerical results of analyses of the p + ¹⁶O reaction at E_p = 135 MeV.     

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 pN 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 p-neutron interaction.     

Color Conductivity at High Resolution: A New Phenomenon of Nuclear Physics

In this paper we discuss in detail the hyothesis that nuclei show extended quark and gluon modes when explored with a high resolution probe. We call this color conductivity at high resolution. We relate color conductivity to the behaviour of proton-proton total and elastic cross sections at high energies. For deep inelastic muon-nucleon scattering we discuss in detail the nuclear evolution equation following from color conductivity and introduced by us previously. The EMC Fe/d data are well described by our theory if due allowance is made for the quoted systematic error. We predict striking effects from color conductivity in the final state of deep inelastic lepton-nucleus scattering. The possibility of making fundamental tests of quantum chromodynamics in leptonnucleus scattering is emphasized. We connect the shadowing phenomenon to the volume and surface terms in the Bethe-Weizsäcker formula for the nuclear binding energy. Finally we point out that deep inelastic scattering on deformed nuclei may be crucial to distinguish between different theories of the EMC effect.     

Structure of 10C and 11C from elastic and inelastic scattering on a proton target

We measured elastic and inelastic scattering to the low-lying states of ¹⁰C and ¹¹C isotopes on a proton target with respective incident energies 45.3 and 40.6 A MeV. Data are analyzed with a microscopic complex potential. Elastic data are sensitive to the rms matter radius, which has been deduced for both isotopes. The moment of the neutron transition density was deduced for ¹⁰C from inelastic scattering.     

Coordinate space structure in the parton model

We study the relation between the parton model and light cone analyses for highly inelastic leptonic processes. Results are displayed which follow from scaling laws in general, independently of specific parton model predictions. We conclude that the assumptions of the light cone analysis of inelastic electron scattering are supported by the parton model. However, the parton model matrix element for massive muon pair production is not light-cone dominated, nor does it have the same light cone singularity as inelastic electron scattering.     

The analysis of elastic and inelastic scattering of alpha particles using a folding potential

The elastic and inelastic scattering of alpha particles from Cd and Te isotopes are analysed in terms of a single folding model in which the scattering potential is approximated by folding an effectiveα-nucleon interaction into the mass distribution of the target nuclei. Excellent fits are obtained to the elastic scattering data. However, to obtain equally good fits to inelastic scattering data arbitrary adjustments of the effective interaction are required.     

THE EMC EFFECT AND THE LIGHT-CONE QUANTUM FIELD THEORY

We indicate that final state interactions can be neglected if one calculate deep inelastic lepton nucleus scattering in the time-ordered perturbation theory in the infinite momentum frame,or its equivalent,the light-cone perturbation theory in an ordinary frame.We thus extend the light-cone quantum field theory to baryon-meson field to establish a relativistic composite model of nuclei,and then apply the impulse approximation to deep inelastic lepton nucleus scattering in this model.