Current Status of Polarized PDFs and Open Issues

RODOLFO SASSOT; MARCO STRATMANN

Seattle

Workshop; Gluons and the Quark Sea at High Energies: Distributions, Polarization, Tomography; 2010

University of Washington

Helicity parton densities, commonly known as polarized PDFs (pPDFs), tell us precisely how the quark and the gluon helicities contribute to that of a nucleon in a helicity eigenstate. These distributions have been on a very close focus from both the theoretical and the experimental sides ever since the completely unexpected finding that little of the proton helicity come from that of the quarks, more than twenty years ago