Showing papers on "Deep inelastic scattering published in 1987"
TL;DR: A set of parameters has been derived for a global optical potential from elastic-nucleus scattering with energies higher than 80 MeV from the geometry and energy dependence derived by Put and Paans.
Abstract: A set of parameters has been derived for a global optical potential from elastic \ensuremath{\alpha}-nucleus scattering with energies higher than 80 MeV. The geometry and energy dependence derived by Put and Paans was adopted. The optical model predictions were tested with data from elastic as well as from inelastic scattering.
127 citations
TL;DR: In this article, the authors compare the differential cross sections of high-mass muon pair production on deuterium and tungsten by incident negative pions of 140 and 286 GeV.
114 citations
TL;DR: Inelastic scattering of 13.8 keV X-rays with very high energy resolution of ΔE=55 meV was used to measure the phonon dispersion curves for theLA andLO modes in the [00ξ] direction in Be. The results agree with inelastic neutron scattering data known from the literature as mentioned in this paper.
Abstract: Inelastic scattering of 13.8 keV X-rays with very high energy resolution of ΔE=55 meV was used to measure the phonon dispersion curves for theLA andLO modes in the [00ξ] direction in Be. The results agree with inelastic neutron scattering data known from the literature. The X-ray scattering intensities of the phonon excitations for different momentum transfers are in very good agreement with the prediction from the scattering law.
57 citations
TL;DR: Deep-inelastic scattering and fission yields have been measured for 58Ni+124Sn at laboratory energies between 230 and 290 MeV in this article, where the authors showed that even at energies below the Coulomb barrier, DLS contributes significantly to the total reaction cross section and has a strength similar to that of fusion.
43 citations
TL;DR: In this paper, a study of deep inelastic 280 GeV muon-nucleon interactions on the transverse momenta and jet properties of the final state hadrons is presented, in a way which attempts to separate the contributions of hard and soft QCD effects from those that arise from the fragmentation process.
Abstract: Results are presented from a study of deep inelastic 280 GeV muon-nucleon interactions on the transverse momenta and jet properties of the final state hadrons. The results are analysed in a way which attempts to separate the contributions of hard and soft QCD effects from those that arise from the fragmentation process. The fragmentation models with which the data are compared are the Lund string model, the independent jet model, the QCD parton shower model including soft gluon interference effects, and the firestring model. The discrimination between these models is discussed. Various methods of analysis of the data in terms of hard QCD processes are presented. From a study of the properties of the jet profiles a value of αs, to leading order, is determined using the Lund string model, namely αs=0.29±0.01 (stat.) ±0.02 (syst.), forQ2∼20 GeV2.
27 citations
TL;DR: In this article, the results of recent experiments on both liquid 3He and 4He are discussed and compared with the results on liquid 4He and 3He, respectively, using deep inelastic neutron scattering for studying the microscopic dynamics of these systems.
Abstract: Liquid helium has been studied for many years because of its unusual properties. The large quantum zero-point motion and the quantum statistics of the particles have a strong effect on the behavior of the liquid. Deep inelastic neutron scattering provides a unique tool for studying the microscopic dynamics of these systems. The results of recent experiments on both liquid 3He and 4He are discussed.
24 citations
14 citations
TL;DR: In this article, the authors reexamine deep inelastic scattering from nuclei under assumptions commonly employed in the literature: that quarks remain confined in hadronic constituents of nuclei, that the nuclear cross section is the average of the free-space cross section of hadron i weighted by the probability of finding i in the nucleus, and that there are no final state interactions between the debris of Hadron i and the rest of the nucleus.
14 citations
TL;DR: In this article, measurements of differential elastic and inelastic cross sections for neutron scattering from 16O at incident energies 18 to 26 MeV are presented in terms of phenomenological optical model potentials.
14 citations
TL;DR: It is shown that the effects of antisymmetrization between the quarks in different nucleons in the nucleus can be very strong and leads to a violation of three commonly used prescriptions: factorization of the nucleon form factor, scaling in quasielastic electron scattering, and separation of nuclear and nucleon effects in Fermi smearing in deep-inelastic electron scatter.
Abstract: It is shown that the effects of antisymmetrization between the quarks in different nucleons in the nucleus can be very strong. Using a schematic model in which a nucleus consists of two identical nucleons with two quarks each, the effects of antisymmetry on the charge form factor, quasielastic response function, Coulomb sum rule, and quark momentum distributions in nuclei are studied. In particular, it is found that the antisymmetrization leads to a violation of three commonly used prescriptions: factorization of the nucleon form factor, scaling in quasielastic electron scattering, and separation of nuclear and nucleon effects in Fermi smearing in deep-inelastic electron scattering.
14 citations
TL;DR: In this article, the Dirac formalism for the elastic scattering of nucleons has been extended to a coupled channel formalism taking into account collective excited states, where the imaginary scalar potential and the imaginary vector potential can be varied widely without giving so large effects on elastic scattering.
TL;DR: With light-front dynamics, the European Muon Collaboration effect is shown to be consistent with this model, with an internal six-quark structure region of average probability of about 20% in medium-mass nuclei, as found in exclusive electron scattering on light nuclei.
Abstract: Deep inelastic structure functions are derived in the hybrid quark-hadron model with three methods for including binding. With light-front dynamics, the European Muon Collaboration effect is shown to be consistent with this model, with an internal six-quark structure region of average probability of about 20% in medium-mass nuclei, as found in exclusive electron scattering on light nuclei; while instant-form dynamics is not consistent with the model.
TL;DR: In this paper, it was shown that the double-folding model description of the experimental data is as good as any description with deformed Woods-Saxon potentials for inelastic scattering of heavy ions from deformed nuclei.
Abstract: The descriptions of heavy-ion inelastic scattering given by the folding model and phenomenological potentials require different degrees of deformation of the optical potential. This is because the rule of equal normalised multipole moments of the optical potential and the nucleon density distribution, imposed by the folding model, conflicts with the rule of equal deformation lengths borne out by analyses with Woods-Saxon potentials. It is shown, in an example of inelastic scattering of heavy ions from deformed nuclei in the region of strong Coulomb-nuclear interference, that the double-folding model description of the experimental data is as good as any description with deformed Woods-Saxon potentials. Thus neither of the two different rules for deforming the optical potential is a universal prescription since they only apply to specific classes of potentials.
TL;DR: The influence of the conventional nuclear structure on the European Muon Collaboration effect is critically reviewed and the ratio of deep inelastic lepton nucleon to lepton nucleus cross sections is shown to be sensitively dependent on the proper kinematics of the Fermi motion and the careful treatment of the binding effect of nucleons in nuclei.
Abstract: The influence of the conventional nuclear structure on the European Muon Collaboration effect is critically reviewed. The ratio of deep inelastic lepton nucleon to lepton nucleus cross sections is shown to be sensitively dependent on the proper kinematics of the Fermi motion and the careful treatment of the binding effect of nucleons in nuclei. We systematically consider the example /sup 40/Ca at -Q/sup 2/ = 20 (GeV/c)/sup 2/.
University of Turin1, Uppsala University2, University of Warsaw3, CERN4, Lancaster University5, RWTH Aachen University6, University of Paris7, University of Kiel8, University of Liverpool9, University of Sheffield10, Max Planck Society11, University of Freiburg12, University of Hamburg13, University of Oxford14
TL;DR: In this article, the authors present results on proton and antiproton production in the target and current fragmentation regions of high energy muon-nucleon scattering in terms of Feynmanx and rapidity.
Abstract: New results on proton and antiproton production in the target and current fragmentation regions of high energy muon-nucleon scattering are presented. Proton and antiproton production is investigated as a function of Feynmanx and rapidity. No significant difference is observed between production on hydrogen and deuterium targets. Correlations betweenpp,\(p\bar p\) and\(\bar p\bar p\) pairs are analysed and the results are compared with the predictions of the Lund fragmentation model.
CERN1
TL;DR: In this article, the similirity and difference of particle production in deep inelastic scattering and e + e − annihilation are discussed, and the predictions for higher energies are made.
TL;DR: In this paper, the authors investigated possible experimental signatures for the existence of both phases of the secondary hadronic phase of the jet evolution and discussed the possibility of a dual correspondence between hadronic and partonic states.
Abstract: Models for hadron production in hard collisions differ widely in the energy scale characteristic of the transition from the primary partonic to the secondary hadronic phase of jet evolution. We investigate possible experimental signatures for the existence of both phases. In particular, we consider multiplicity and energy moments, long range charge correlations and angular correlations as a function of total energy or near the exclusive two body limit ine
+
e
− annihilation and deep inelastic scattering processes. The possibility of a dual correspondence between hadronic and partonic states is discussed.
TL;DR: In this paper, the inelastic scattering of antiprotons (plab=600 MeV/c) by 12C leading to the excitation of the three lowest normal parity T = 0 levels is studied in the framework of the Glauber model and the distorted wave impulse approximation.
Abstract: The inelastic scattering of antiprotons (plab=600 MeV/c) by 12C leading to the excitation of the three lowest normal parity T=0 levels is studied in the framework of the Glauber model and the distorted wave impulse approximation. The transition densities obtained from fitting the electron scattering data and the elementary two-body amplitudes derived from analysis of pp scattering data are used in the calculation. Distortion effects are taken into account by the elastic p-nucleus scattering amplitudes. The results are seen to be in fairly good agreement with the available experimental data.
TL;DR: It is shown that the production ratio for oppositely charged hadrons h/sup +//h/sup -/ for the same nucleus is quite insensitive to nuclear effects, and the ratio of cross sections for production of the same-sign hadron from different nuclei is a quantity for which sizable nuclear effects are predicted.
Abstract: We evaluate the possibility of observing nuclear effects in electroproduction of hadrons (h) from nuclei. Explicit calculations in the quark-cluster model show that the production ratio for oppositely charged hadrons h/sup +//h/sup -/ for the same nucleus is quite insensitive to nuclear effects. On the other hand, the ratio of cross sections for production of the same-sign hadron from different nuclei is a quantity for which sizable nuclear effects are predicted.
TL;DR: A quantum mechanical interpretation of the density matrix of the time-dependent Hartree-Fock theory for heavy ion scattering is suggested, which provides, in principle, a theoretical method of obtaining exclusive amplitudes.
Abstract: We suggest a quantum mechanical interpretation of the density matrix of the time-dependent Hartree-Fock theory for heavy ion scattering. We show how with this interpretation the time-dependent Hartree-Fock equations can be derived provided we admit (i) a generalized factorization of a suitably defined average of two-body density matrix elements in terms of a sum of products of the corresponding one-particle elements and (ii) additional semiclassical approximations which convert a sum of products into an antisymmetric product of sums. These ideas, previously recognized within the framework of soliton models, are extended here to include inelastic processes with the excitation of collective modes as the mechanism for producing deep inelastic scattering. An essential feature of the approach is that it provides, in principle, a theoretical method of obtaining exclusive amplitudes. We describe how these might be calculated.
1 Dec 1987
TL;DR: In this article, the authors used scheme-invariant perturbation theory to determine the value of R = sigma/sub L/ sigma /sub T/ by means of scheme invariance.
Abstract: The ..cap alpha../sub s/ correction to the longitudinal structure function for deep inelastic scattering is calculated. The result is used to determine the value of R = sigma/sub L// sigma/sub T/ by means of scheme-invariant perturbation theory. It is shown that inclusion of the nonleading contribution improves the agreement with experiment.
TL;DR: A review of data and theoretical interpretations of the nuclear dependence of quark and antiquark distributions as observed in the deep inelastic scattering of neutrinos and charged leptons from nuclei is presented in this article.
Abstract: A review is presented of data and theoretical interpretations of the nuclear dependence of quark and antiquark distributions as observed in the deep inelastic scattering of neutrinos and charged leptons from nuclei. After a summary of the experimental situation and a survey of proposed explanations, I concentrate on interpretations in terms of conventional nuclear physics and on the Q2-rescaling approach. The review concludes with a list of desirable future experiments.
TL;DR: Measurements of asymmetries arising in deep-inelastic scattering of longitudinally polarized electrons and positrons from polarized nucleons will test models for spin structure of the nucleon and the standard model.
Abstract: Asymmetries arising in deep-inelastic scattering of longitudinally polarized electrons and positrons from polarized nucleons are considered. The behavior of these asymmetries arising from electroweak effects is estimated for collider energies. Such measurements will test models for spin structure of the nucleon and the standard model.
TL;DR: In this paper, the mass splitting of scalar quarks of the same flavour leads to parity violation in deep inelastic scattering, even at one photon exchange level, and the effect modifies the asymmetries measured in the polarized lepton-proton scattering.
Abstract: The mass splitting of scalar quarks of the same flavour leads to parity violation in deep inelastic scattering, even at one photon exchange level. This effect modifies the asymmetries measured in the polarized lepton-proton scattering. We calculate them in leading order and give numerical estimates of their shapes.
TL;DR: In this article, the role of weak neutral currents in the quark-parton model with regard to hadronic radiation and leptonic was investigated, and various P-odd effects were investigated to distinguish the weak current contribution.
Abstract: We consider the role of weak neutral currents in the processesl± + N→l± + γ + X. In the quark-parton model, with regard to hadronic radiation as well as leptonic, we obtain the differential cross-section of the processes, and investigate various P-odd effects that allow us to distinguish the weak current contribution.
TL;DR: In this paper, a high statistics study of the nucleon structure function F 2 ( x, Q 2 ) measured in deep inelastic scattering of muons on carbon in the kinematic range 0.25⩽ x ⩽0.80 and Q 2 ⩾25 GeV 2.