Global analysis of helicity parton densities and their uncertainties.

DANIEL DE FLORIAN,; RODOLFO SASSOT; MARCO STRATMANN; WERNER VOGELSANG

PHYSICAL REVIEW LETTERS

The American Physical Society

Lugar: Ridge, New York, EEUU; Año: 2008 vol. 101 p. 2001 - 2004

0031-9007

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 pp 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 to incorporate 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.