Parametrization of polarized parton distributions
Abstract
Description
We report the polarized parton distributions proposed by the Asymmetry Analysis Collaboration (AAC). Using parametrized distributions at Q^2=1 GeV^2 and measured A_1 data, we determine optimum polarized distributions in the leading order (LO) and next-to-leading order (NLO). We find that the polarized antiquark distribution is not well determined particularly at small x. It could lead to a rather small quark spin content in comparison with usually-quoted values of 10-30%. In our analysis, it varies from 5% to 28% depending on the small-x extrapolation. It is necessary to have small-x (<10^{-3}) data for precise determination. In addition, the large-x region should be also studied for Δq-bar, which cannot be determined solely by g_1. We propose three sets of distributions as the longitudinally polarized parton distribution functions.
5 pages LATEX, moriond.sty, amsmath.sty, epsfig.sty, wrapfig.sty, 6 eps figures. Talk at the XXXVth Rencontres de Moriond "QCD and High Energy Hadronic Interactions", Les Arcs, France, March 18-25, 2000, to be published in proceedings. Complete postscript file and conference transparencies are available at http://www-hs.phys.saga-u.ac.jp Email: kumanos@cc.saga-u.ac.jp
5 pages LATEX, moriond.sty, amsmath.sty, epsfig.sty, wrapfig.sty, 6 eps figures. Talk at the XXXVth Rencontres de Moriond "QCD and High Energy Hadronic Interactions", Les Arcs, France, March 18-25, 2000, to be published in proceedings. Complete postscript file and conference transparencies are available at http://www-hs.phys.saga-u.ac.jp Email: kumanos@cc.saga-u.ac.jp