Related papers: Up and Down Quark Contributions to Spin Content of…
In these proceedings we discuss recent progress in nucleon structure using lattice QCD simulations at or near the physical value of the pion mass. Main focus will be given in observables such as the nucleon axial charge and the first…
The strange quark helicity distribution Delta s(x)is derived at LO from the semi-inclusive and inclusive spin asymmetries measured by the COMPASS experiment at CERN. The significance of the results is found to depend critically on the ratio…
A next-to-leading order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton nucleon scattering is presented within the framework of the radiative parton model. A consistent NLO formulation of the…
The quark-parton model calculation including the effects of intrinsic transverse momentum and of all six twist-two distribution functions of quarks in polarized nucleons is performed. It is demonstrated that new twist-two quark distribution…
The representation of quark distribution and fragmentation functions in terms of non-local operators is combined with a simple spectator model. This allows us to estimate these functions for the nucleon and the pion ensuring correct…
To extract information about the polarized gluon distribution, $\dg$, in the nucleons, we propose Lambda_c^+ productions in polarized pp scattering, p + \vec{p} \to \vec{Lambda_c^+} + X, which will be observed at RHIC experiment starting…
We make a systematic study of the isospin symmetry of fragmentation functions by taking decay contributions into account. We assume the isospin symmetry in strong interactions and show that in the unpolarized case the isospin symmetry is…
We present a fit to spin asymmetries which gives polarized quark distributions. These functions are closely related to the ones given by the newest Martin, Roberts and Stirling fit for unpolarized structure functions. The integrals of…
It is shown that the longitudinal double spin asymmetry $A_{ll}$ in polarized diffractive $Q \bar Q$ production depends strongly on the spin structure of the quark-pomeron vertex. Relevant experiments will be possible at HERA with a…
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…
We propose new method which allows determination of the strange-sea quark spin distribution in the nucleon through measurement of various inclusive and semi-inclusive polarized deep inelastic electron- or muon-proton reactions. It is shown,…
I introduce a gauge invariant decomposition of the nucleon spin into quark helicity, quark orbital, and gluon contributions. The total quark (and hence the quark orbital) contribution is shown to be measurable through virtual Compton…
The difference between the $\Lambda$ and $\bar \Lambda$ longitudinal spin transfers in the semi-inclusive deep inelastic scattering process is intensively studied. The study is performed in the current fragmentation region, by considering…
A previous approach with Fermi-Dirac distributions for fermion partons is here improved to comply with the expected low $x$ behaviour of structure functions. We are so able to get a fair description of the unpolarized and polarized…
I review recent theoretical results on polarized deep inelastic lepton nucleon scattering. Some specific issues, like $Q^2$ evolution of structure functions, the small $x$ behaviour, and the determination of polarized parton densities, are…
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…
Inclusive and semi-inclusive deep inelastic leptoproduction offers possibilities to study details of the quark and gluon structure of the hadrons involved. In many of these experiments polarization is an essential ingredient. We also…
Spin-dependent quark densities, matrix elements of specific density operators in proton states of definite spin-polarization, indicate that the nucleon may harbor an infinite variety of non-spherical shapes. We show that these matrix…
We investigate the production of spin-3/2 hadrons in semi-inclusive deep inelastic lepton-nucleon scatterings. The complete differential cross section is derived through the kinematic analysis and expressed in terms of 288 structure…
A QCD analysis of the world data on inclusive polarized deep inelastic scattering of leptons on nucleons is presented in leading and next-to-leading order. New parameterizations are derived for the quark and gluon distributions and the…