Related papers: Polarized Parton Densities and Processes
High-energy spin-polarized electron, positron, and $\gamma$-photon beams have many significant applications in the study of material properties, nuclear structure, particle physics, and high-energy astrophysics. Thus,efficient production of…
Recent measurements of QCD interactions involving large momentum transfers are reviewed. The status of measurements of the strong coupling constant is summarised. Recent developments in the measurement and interpretation of deep inelastic…
The main focus of the physics program at PHENIX and STAR that makes use of RHIC's polarized proton beams is to figure out how and if at all the gluons inside protons are polarized, or to put it another way, do the spin 1 gluons prefer to…
The study of two spin asymmetries in hadron-hadron collisions probes the details of fundamental particle interactions in ways infeasible to machines with unpolarized collisions. Within reach is how the proton spin is distributed among its…
The results on polarized parton densities (PDFs) obtained using different methods of QCD analysis of the present polarized DIS data are discussed. Their dependence on the method used in the analysis, accounting or not for the kinematic and…
We discuss the production of hadrons in polarized lepton nucleon interactions and in the current jet fragmentation region; using the QCD hard scattering formalism we compute the helicity density matrix of the hadron and show how its…
A selection of theoretical and experimental results are presented in the broader context of understanding QCD and its relation to photon physics. A phenomenological analysis of HERA data to constrain the gluon content of the proton and…
Deep inelastic electron proton scattering at HERA II will allow precise studies of QCD and stringent tests of physics beyond the standard model. We discuss these two aspects of DIS with emphasis on the regime of high gluon densities at…
Results of our next-to-leading order analytic calculation for longitudinally polarized photoproduction of heavy quarks are presented. Certain differential cross sections and the corresponding asymmetries are computed for energy ranges…
Single spin asymmetries in polarized proton(antiproton) + proton -> pion + X have been measured to be large. They can be understood within perturbative QCD by introducing new k_perp and spin dependences in fragmentation and/or distribution…
We give an overview of the current status of investigations of the polarization of gluons in the nucleon. We describe some of the physics of the spin-dependent gluon parton distribution and its phenomenology in high-energy polarized…
Several topics from the wide field of QCD studies in Deep-inelastic $ep$ Scattering at HERA are addressed. They include QCD analyses of the inclusive cross section with the determination of $\alpha_s$ and the proton gluon density from the…
We briefly discuss the status of double parton scattering (DPS) on both theoretical and experimental sides and summarize the state of the naive DPS model, where the scatterers are taken completely independent. We then elaborate on some of…
I briefly review: (a) some recent developments in the theory of hard scattering in QCD with polarized beams, and (b) coherent hard diffraction (that is, hard scattering in diffractive events, with the Pomeron behaving in an apparently…
Compton scattering results are used to probe proton structure via measurement of higher order polarizabilities. Values for $\alpha_{E2}^p,\beta_{E2}^p,\alpha_{E\nu}^p,$ $\beta_{E\nu}^p$ determined via dispersion relations are compared to…
High energy scattering processes of charged particles are accompanied by radiation of hard photons. Emission collinear to the incident particles, which leads to a reduction of the effective beam energy, and the possibility to directly…
We review how RHIC is expected to deepen our understanding of the spin structure of longitudinally polarized nucleons. After briefly outlining the current status of spin-dependent parton densities and pointing out open questions, we focus…
We investigate the possibility to measure the spin content carried by the different quark flavors in a nucleon by means of polarized deep inelastic scattering with $W^\pm$ exchange at HERA. Such measurements require a polarized proton beam.…
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…
As a guideline for future experiments to extract the four (leading) spin polarizabilities of the nucleon, we have constructed the forward amplitude for polarized Compton scattering by dispersion integrals. These integrals have been…