相关论文: Target independence of the `proton spin' effect

An approach to deep inelastic scattering is described in which the matrix elements arising from the operator product expansion are factorised into composite operator propagators and proper vertex functions. In the case of polarised $\m p$…

The target-independent suppression mechanism proposed as an explanation of the EMC-SMC `proton spin' effect is reviewed and compared to current experimental data. According to this proposal, the anomalous suppression observed in the first…

A natural consequence of the composite operator propagator-vertex description of deep inelastic scattering developed by the authors is that the anomalous suppression observed in the flavour singlet contribution to the first moment of the…

We have measured the spin-dependent structure function $g_1^p$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003 < x < 0.7$ and $1 GeV^2 < Q^2 < 60 GeV^2$. A next-to-leading order…

We have measured the spin-dependent structure function $g_1^p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}^2<Q^2<60\,\mbox{GeV}^2$. Its first…

The theory of the `proton spin' effect proposed in our earlier papers is extended to include the chiral SU(3) symmetry breaking and flavour mixing induced by non-vanishing quark masses in QCD. The theoretical basis is the derivation of…

We revisit the effects of QCD instantons in semi-inclusive deep inelastic scattering (SIDIS). We show that large single spin asymmetry (SSA) effects can be induced in longitudinally and transversely polarized proton targets. The results are…

The inclusive double-spin asymmetry, A_1^p, has been measured at COMPASS in deepinelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q2 > 1 (GeV/c)^2, 0.004 < x < 0.7…

Topological charge screening has been proposed as the mechanism responsible for the anomalous suppression in the first moment of the polarized proton structure function -- the `proton spin' effect. An immediate consequence is that this…

In the one-photon exchange approximation we discuss questions related to the interpretation of unexpected results of the JLab polarization experiments to measure the Sachs form factors ratio $G_E/G_M$ in the region $1. 0 \leq Q^2 \leq 8.5$…

We discuss semi-inclusive Deep Inelastic Scattering (DIS) in the z -> 1 limit, in particular the relationship between fracture functions, generalised cut vertices and Green functions of the composite operators arising in the OPE. The…

The theoretical status of the `proton spin' effect is reviewed. The conventional QCD parton model analysis of polarised DIS is compared with a complementary approach, the composite operator propagator-vertex (CPV) method, each of which…

We present a Next-to-Leading order perturbative QCD analysis of world data on the spin dependent structure functions $g_1^p, g_1^n$, and $g_1^d$, including the new experimental information on the $Q^2$ dependence of $g_1^n$. Careful…

We review the theory and phenomenology of deep inelastic polarized lepton-nucleon scattering in the light of recent data with a deuteron target from the SMC at CERN and a Helium 3 target from the E142 experiment at SLAC. After including…

The proton spin puzzle inspired by the EMC experiment and its present status are closely examined. Recent experimental progress is reviewed. Various factorization schemes due to the ambiguity arising from the axial anomaly are discussed.…

The forward Compton scattering off the proton is determined by substituting the empirical total photoabsorption cross sections into dispersive sum rules. In addition to the spin-independent amplitude evaluated previously [Phys. Rev. D 92,…

The neutron longitudinal and transverse asymmetries $A^n_1$ and $A^n_2$ have been extracted from deep inelastic scattering of polarized electrons by a polarized $^3$He target at incident energies of 19.42, 22.66 and 25.51 GeV. The…

In the past year, polarized deep inelastic scattering experiments at CERN and SLAC have obtained structure function measurements off proton, neutron and deuteron targets at a level of precision never before achieved. The measurements can be…

We present the results of our final analysis of the full data set of g_1^p(Q^2), the spin structure function of the proton, collected using CLAS at Jefferson Lab in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2 and 5.7 GeV…

We discuss questions related to the interpretation of unexpected results of measurements of the proton form factors ratio G_E/G_M in the polarization experiments done in JLab in the region of 0.5 < Q^2 < 8.5 GeV^2. For this purpose, in the…