title: Global analysis of helicity parton densities and their uncertainties.
abstract: We present a new analysis of the helicity parton distributions of the nucleon. The analysis takes into account the available data from inclusive and semi-inclusive polarized deep inelastic scattering, as well as from polarized proton-proton (p-p) scattering at RHIC. For the first time, all theoretical calculations are performed fully at next-to-leading order (NLO) of perturbative QCD, using a method that allows incorporation of the NLO corrections in a very fast and efficient way in the analysis. We find evidence for a rather small gluon polarization in the nucleon, over a limited region of momentum fraction, and for interesting flavor patterns in the polarized sea.
authors.affiliation: Departamento de Fisica, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1 (1428) Buenos Aires, Argentina.
authors.forename: Daniel
authors.initials: D
authors.lastname: de Florian
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Sassot
authors.forename: Marco
authors.initials: M
authors.lastname: Stratmann
authors.forename: Werner
authors.initials: W
authors.lastname: Vogelsang