  We present a first global determination of spin-dependent parton distribution
functions (PDFs) and their uncertainties using the NNPDF methodology:
NNPDFpol1.1. Longitudinally polarized deep-inelastic scattering data, already
used for the previous NNPDFpol1.0 PDF set, are supplemented with the most
recent polarized hadron collider data for inclusive jet and $W$ boson
production from the STAR and PHENIX experiments at RHIC, and with open-charm
production data from the COMPASS experiment, thereby allowing for a separate
determination of the polarized quark and anti-quark PDFs, and an improved
determination of the medium- and large-$x$ polarized gluon PDF. We study the
phenomenological implications of the NNPDFpol1.1 set, and we provide
predictions for the longitudinal double-spin asymmetry for semi-inclusive pion
production at RHIC.
