Polarised quark distributions are extracted from semi-inclusive deep inelastic scattering data, which include the additional detection of a leading hadron to providestatisticaìàvour-tagging'. Results are combined from both proton and`neutron' targets to isolate the contributions to the nucleon spin of the individual quark avours, including the sea quarks. Spin asymmetries in the semi-inclusive ...

The helicity dependent parton distributions describe the number density of partons with given longitudinal momentum x and given polarization in a hadron polarized longitudinally with respect to its motion. After the discovery , more than 70 years ago , that the proton is not elementary , the observation of Bjorken scaling in the late 1960s lead to the idea of hadrons containing almost pointlike...

We propose to use transverse momentum p T distribution of J / ψ production at the future Electron Ion Collider (EIC) explore mechanism heavy quarkonia in high energy collisions. apply QCD and QED collinear factorization a c ¯ </m...

We study the analytic structure of light-front wave functions (LFWFs) and its consequences for hadron form factors using an explicitly Lorentz-invariant formulation of the front form. The normal to the light front is specified by a general null vector ω. The LFWFs with definite total angular momentum are eigenstates of a kinematic angular momentum operator and satisfy all Lorentz symmetries. Th...

COMPASS is a high-energy physics experiment operating at the SPS at CERN. Wide physics program of the experiment comprises study of hadron structure and spectroscopy with high energy muon and hadrons beams. As for the muon-program, one of the important objectives of the COMPASS experiment is the exploration of the transverse spin structure of the nucleon via spin (in)dependent azimuthal asymmet...

We discuss 1 a possible explanation of the 25 year old mystery of the large transverse spin asymmetries found in many semi-inclusive hadron-hadron reactions. We obtain the first reliable information about the transverse polarized quark densities ∆T q(x) and we find surprising implications for the usual, longitudinal, polarized DIS. The plan of the presentation is as follows: 1) A brief reminder...

The equivalence is found between high–energy QCD in the generalized leading logarithmic approximation and the one-dimensional Heisenberg magnet. According to Regge theory, the high energy asymptotics of hadronic scattering amplitudes are related to singularities of partial waves in the complex angular momentum plane. In QCD, the partial waves are determined by nontrivial two-dimensional dynamic...

HADRON '97 covered a wide spectrum of particle physics, from high-Q 2 events in e +-proton collisions at DESY to the recent discovery of 1 ?+ exotic mesons. This paper reviews progress reported at the conference, in particular the status of glueballs and hybrids. Personal views and interpretations are oofered, sometimes at variance with accepted views. The role of gluons in hadron spectroscopy ...

Using the AdS/CFT correspondence, we calculate the polarized structure functions in strongly coupled N = 4 supersymmetric Yang–Mills theory deformed in the infrared. We find that the flavor singlet contribution to the g1 structure function is vanishingly small, while the flavor non–singlet contribution shows the Regge behavior at small–x with an intercept slightly less than 1. We explicitly che...