Related papers: Spin structure function of the virtual photon
The photo-production of nucleon resonances is calculated based on a chiral constituent quark model including both relativistic corrections H{rel} and two-body exchange currents, and it is shown that these effects play an important role. We…
The studies of influence of spin on a photon's motion in a Schwartzschild spacetime is continued. In the previous paper [13] the first order correction to the geodesic motion is found for the first half of the photon world line. The system…
This is the first of two papers in which we study real and virtual photon-proton scattering in a nonperturbative framework. We classify different contributions to this process and identify the leading contributions at high energies. We then…
The LEP experiments are making real progress in understanding the structure of the photon, though the results do not yet give such clear demonstrations of QCD in action as the proton structure has done. Other new results are reported,…
We propose an optical counterpart of the quantum spin Hall (QSH) effect in a two-dimensional photonic crystal composed of a gyrotropic medium exhibiting both gyroelectric and gyromagnetic properties simultaneously. Such QSH effect shows…
We review the present understanding of the spin structure of protons and neutrons, the fundamental building blocks of nuclei collectively known as nucleons. The field of nucleon spin provides a critical window for testing Quantum…
The structure of the electromagnetic vertex of spin-1 particles are studied in a general way, for the diagonal as well as the off-diagonal couplings. In each case, we consider in detail the consequences of gauge invariance and the…
We point out that in processes involving the parton content of the photon the usual effective photon approximation should be modified. The reason is that the parton content of virtual photons is logarithmically suppressed compared to real…
The present knowledge of the structure of the photon is presented based on results obtained by measurements of photon structure functions at e+e- collider. Results are presented both for the QED structure of the photon as well as for the…
We present a measurement of the deuteron spin-dependent structure function g1d based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for Gamma_1^d, the first moment…
Theoretical description of the spin dependent structure function g_1(x,Q^2) in the region of low values of x and Q^2 is presented. It contains the Vector Meson Dominance contribution and the QCD improved parton model suitably extended to…
Band topology and related spin (or pseudo-spin) physics of photons provide us with a new dimension for manipulating light, which is potentially useful for information communication and data storage. Especially, the quantum spin Hall effect…
The present status of the nucleon's spin structure is reviewed with emphasis on new experimental results.
We emphasise the relation between the spin structure of the proton and the axial U(1) problem. New experiments motivated by the proton spin problem which could shed light on the nature of U(1) symmetry breaking in QCD are discussed.
The photon is a very interesting object for QCD studies since it has both a pointlike coupling to quarks, which yields a perturbative part of photon's wave function, and a non-perturbative coupling related to the magnetic susceptibility of…
The pion structure function is investigated in a simple model, where the pion and its constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi -> gamma* pi scattering…
Twist-2 components of the real and virtual photon distribution amplitudes are evaluated in several chiral quark models. The results, obtained at the quark model scale, are then evolved to higher scales, probed in experiments or in lattice…
We generalize the sum rules for the nucleon electric plus magnetic polarizability $\Sigma=\alpha+\beta$ and for the nucleon spin-polarizability $\gamma$, to virtual photons with $Q^2>0$. The dominant low energy cross sections are…
The possibility to constrain the meson distribution amplitude from the transitions of virtual photons to pseudoscalar mesons is investigated. It is shown that for a large range in the two photon virtualities the transition form factors are…
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…