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Parametrization of polarized parton distributions

S. Kumano
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Abstract

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.

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S. Kumano. 2000-05-12. Parametrization of polarized parton distributions. https://arxiv.org/abs/hep-ph/0005117

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