Determination of polarized parton distribution functions with recent data on polarization asymmetries

Global analysis has been performed within the next-to-leading order in quantum chromodynamics (QCD) to determine polarized parton distributions with new experimental data in spin asymmetries. The new data set includes J-Lab, HERMES, and COMPASS measurements on spin asymmetry A(1) for the neutron and deuteron in lepton scattering. Our new analysis also utilizes the double-spin asymmetry for pi(0) production in polarized pp collisions, A(LL)(pi 0), measured by the PHENIX Collaboration. Because of these new data, uncertainties of the polarized PDFs are reduced. In particular, the J-Lab, HERMES, and COMPASS measurements are valuable for determining Delta d(v)(x) at large x and Delta(q) over bar (x) at x similar to 0.1. The PHENIX pi(0) data significantly reduce the uncertainty of Delta g(x). Furthermore, we discuss a possible constraint on Delta g(x) at large x by using the HERMES data on g(1)(d) in comparison with the COMPASS ones at x similar to 0.05.