Related papers: Polarized Lambda Production at HERA
Recent results from HERA are presented. The main reviewed subjects are polarized DIS cross sections, parton density determination, diffractive PDFs, multi-jet production and searches for physics beyond the Standard Model.
Recent measurements of inclusive and semi-inclusive deep inelastic scattering in electron-proton collisions at HERA are reviewed. These measurements are used to determine the parton distribution functions (PDFs) of the proton, a necessary…
Physics from the polarized electron or positron beam colliding with the unpolarized proton beam at HERA-II as well as from the unpolarized ep collisions at HERA-I is discussed. Results shown include (i) inclusive neutral and charged current…
Multiple polarization observables must be measured to access the amplitude structure of pseudoscalar meson photoproduction off the proton. The hyperon-producing reactions are especially attractive to study, since the weak decays allow…
Neutral-current (NC) and charged-current (CC) deep inelastic scattering (DIS) interactions have been studied in electron-proton and positron-proton collisions with longitudinally polarised lepton beams using the H1 and ZEUS detectors at…
Presented here is a calculation of inelastic $J/\psi$ production in polarized photon-hadron collisions under the framework of NRQCD factorization formalism. We consider the photoproduction of $\jpsi$ in the energy range relevant to HERA.…
We present a thorough phenomenological analysis of the experimental data from Belle Collaboration for the transverse $\Lambda$ and $\bar\Lambda$ polarisation, measured in $e^+e^-$ annihilation processes, for the case of inclusive (plus a…
By combining recent HERMES data on semi-inclusive DIS $\pi^\pm$-production with the singlet fragmentation function $D_\Sigma^{\pi^+}$, which is well determined from $e^+e^-$ data, we are able to extract, for the first time, the flavoured…
Processes of heavy quark photoproduction at HERA energies and beyond are investigated using the semihard ($k_{\bot}$ factorization) approach. Virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the…
The role of hadronization mechanism in polarization phenomena in semi inclusive deep inelastic scattering (SIDIS) and a purity method for extraction of polarized distribution functions are discussed. According to the Monte Carlo (MC) event…
Experiments at HERA looking for deep-inelastic electroproduction of neutrons in the proton fragmentation region are in progress. They are aimed to measure the pion structure function at small Bjorken $x$. The important condition for such a…
We study inclusive photoproduction of hadrons at HERA via both direct and resolved photons to next-to-leading order (NLO) in the QCD-improved parton model. We predict transverse-momentum ($\pt$) and rapidity ($\ylab$) distributions and…
The production rates of lepton-photon and dimuon pairs at the HERA collider and the HERMES experiment are evaluated in the leading order equivalent photon approximation. It is shown that the production rates are sufficient to facilitate the…
STAR collaboration at RHIC has recently measured the polarization of $\Lambda$ hyperons in non-central heavy ion collisions in the RHIC Beam Energy Scan (BES) program. The magnitude of the polarization was found to decrease from few…
We predict the polarization of Lambda and antiLambda hyperons in peripheral heavy ion collisions at ultrarelativistic energy, based on the assumption of local thermodynamical equilibrium at freeze-out. The polarization vector is…
This article describes different approaches to investigate the behavior of parton evolution in the proton by exploiting various aspects of the hadronic final state produced in Deep Inelastic Scattering Events at HERA.
A recent global QCD analysis of jet production and other polarized scattering data has found the presence of negative solutions for the gluon helicity distribution in the proton, $\Delta g$, along with the traditional $\Delta g > 0$…
The Common Muon Proton Apparatus for Structure and Spectroscopy (COMPASS) at CERN with its use of beams of naturally polarized muons scattered of a polarized deuteron target, provides an environment of hard scattering between quasi-real…
Two related issues are discussed, which might be easily explored by present and future COMPASS experiments. The first one deals with the new world of transversity, the fundamental polarized parton distribution so far totally unknown. The…
The physics programme for a possible fixed target polarized nucleon-nucleon collision experiment aiming at studying the nucleon spin structure at HERA is described. The experiment named HERA-N could be realized using an internal polarized…