相关论文: Note on spin carried by quarks
New experimental results on the spin dependent structure functions g_1 and g_2 which are determined from deep-inelastic scattering experiments at CERN, SLAC and DESY are reported. These results are used to evaluate the Bjorken sum rule and…
We present a discourse on the stages of discovery that have led to a deeper understanding of the role played by strange quarks in the structure of the nucleon.
The alternative to the standard formulation of the quark-parton model is proposed. Our relativistically covariant approach is based on the solution of the master equations relating the structure and distribution functions, which…
Particle production in deep inelastic scattering on nuclei is reduced due to absorption of the produced particles in the nucleus. The photon ejects a quark from a bound nucleon which propagates through the nucleus forming a prehadron before…
This talk explores our lack of knowledge of the strange quark contribution to the nucleon spin, $\Delta s$. Data on $\Delta s$ from inclusive and semi-inclusive polarized deep-inelastic scattering will be reviewed, followed by a discussion…
Extraction of electrons from a semiconductor to a ferromagnet as well as the case of injection in the reverse direction may be formulated as a scattering theory. However, the presence of bound states at the interface arising out of doping…
Restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group are considered in detail. We argue that the present theory of deep inelastic…
We present a systematic QCD analysis of the strange--charm and bottom--top contributions to transverse and longitudinal structure functions in charged--current deep inelastic scattering. Various ${\cal O}(\alpha_s^1)$ schemes are studied…
Deep inelastic structure functions for the nucleon are obtained in a constituent quark model on the light cone. Parton model formulas are derived. The negative slope of $F_{2}^{n}/F_{2}^{p} requires attraction between scalar quark pairs.…
The quark helicity measured in polarized deep inelastic scattering is different from the quark spin in the rest frame of the nucleon. We point out that the quark spin distributions $\Delta q_{RF}(x)$ are connected with the quark helicity…
We investigate the sea quark polarization in the nucleon by means of a combined next to leading order analysis to the recently enlarged set of inclusive and semi-inclusive polarized deep inelastic scattering data. Using the Lagrange…
Data from H1 and ZEUS on the structure and the quark and gluon densities of the proton are discussed. A brief excursion is made into the field of inclusive diffraction by deep inelastic scattering. The comparison of e- p and e+ p scattering…
The main focus of these lectures is on those aspects of deep inelastic scattering that can be derived directly from QCD using quantum field theory, without recourse to phenomenological models. The emphasis is on spin dependent scattering,…
Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized nucleon targets have been under intense experimental investigation over the past few years. They provide new insights into QCD and the nucleon…
We survey contemporary studies of hadrons and strongly interacting quarks using QCD's Dyson-Schwinger equations, addressing: aspects of confinement and dynamical chiral symmetry breaking; the hadron spectrum; hadron elastic and transition…
Considerable progress has been made in our knowledge of the spin distribution within the proton. The recently measured limits on polarized gluons in the proton suggest polarized gluons contribute very modestly to the proton spin. We will…
The spin effects at high energies and momenta transferred $|t|>1 GeV^2$ are analysed for quark-photon scattering. The energy independence of the ratio of spin-flip and spin-non-flip amplitudes in the same $\alpha_s$ order of QCD is…
We have used recent polarized deep-inelastic scattering data from CERN and SLAC to extract information about nucleon spin structure. We find that the SMC proton data, the E142 neutron data and the deuteron data from SMC and E143 give…
The measurements of the hadronic final state in deep inelastic scattering at HERA are reviewed and discussed in the context of QCD. Covered are the general event properties in terms of energy flows, charged particle production, and charm…
The question how the spin of the nucleon is distributed among its quark and gluon constituents is still a subject of intense investigations. Lattice QCD has progressed to provide information about spin fractions and orbital angular momentum…