Related papers: Spinning protons and gluons in the $\eta'$
We compute the full x - dependence of the proton and neutron spin structure functions in the MIT bag model, including the effect of gluon exchange and the meson cloud. Impressive agreement is found for x larger than 0.1, where polarised…
The investigation of a proposed glueball filter in proton-proton collisions led us to show that its action is in fact easily understood in terms of kinematics. While the procedure proposed stays of interest in reducing background when…
We argue that a large fraction of the proton spin comes from a contribution due to a nonperturbative intrinsic charm component of the proton. An account of this contribution removes an apparent contradiction between the data and exact…
We show how deeply virtual pseudoscalar meson production experiments single out the contribution of the four chiral odd quark-proton GPDs which are related to the so far elusive transversity distribution function, $h_1$. Furthermore, in the…
The status of lattice calculations of the quark spin, the quark orbital angular momentum, the glue angular momentum and glue spin in the nucleon is summarized. The quark spin calculation is recently carried out from the anomalous Ward…
The part of the proton spin $\Sigma$ carried by $u, d, s$ quarks is calculated in the framework of the QCD sum rules in the external fields. The operators up to dimension 9 are accounted. An important contribution comes from the operator of…
We present results of investigations aiming to determine the hadronic interaction of eta and eta-prime mesons with nucleons. Inferences are based on comparisons of both the differential cross sections and the close-to-threshold excitation…
Recently it was suggested that inside the hadrons there are additional partons - tensorgluons - which carry the same charges as the gluons, but have larger spin. The nonzero density of tensorgluons can be created inside a nucleon by…
The high density parton effects are strongly dependent of the spatial gluon distribution within the proton, with radius $R$, which cannot be derived from perturbative QCD. In this paper we assume that the unitarity corrections are present…
We discuss the spin structure of the proton in a light-cone treatment of the chiral quark model. Based on the fact that the quark helicity ($\Delta q$) measured in polarized deep inelastic scattering experiments is actually the quark spin…
We perform the first Lattice calculation about the charmed hadron spin decomposition using overlap fermions on a 2+1 flavor RBC/UKQCD domain-wall gauge configurations at 0.083 fm with 300 MeV pion mass. It is found that the contributions of…
Light-front quantized quark and gluon states (partons) play a dominant role in high energy scattering processes. Initial state hadrons are mixed ensembles of partons, while produced pure partonic states appear as mixed ensembles of hadrons.…
We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in…
We revisit the scale evolution of the quark and gluon spin contributions to the proton spin, $\frac{1}{2}\Delta \Sigma$ and $\Delta G$, using the three-loop results for the spin-dependent evolution kernels available in the literature. We…
Measurements involving the gluon spin density, Delta G=G++ - G+-, can play an important role in the quantitative understanding of proton structure. To demonstrate this, we show that the shape of the gluon asymmetry, A(x,t)=Delta…
We construct a three flavor chiral Lagrangian of pseudoscalars and vectors with special emphasis on the symmetry breaking terms. Comparing tree level two and three point functions with experiment allows us to first, fix the parameters of…
We study the covariant version of the quark-parton model, in which the general rules of the angular momentum composition are accurately taken into account. We demonstrate how these rules affect the relativistic interplay between the quark…
Quarks and gluon, as quantum particles, are subjects to various effects that go beyond the naive parton picture and are not captured by ordinary parton densities. In this work, we investigate the twist-three parton distribution functions,…
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.…
We have utilized the concept of valon model to calculate the spin structure functions of proton, neutron and deuteron. The valon structure itself is universal and arises from the perturbative dressing of the valence quark in QCD. Our…