Determination of polarized parton distribution functions and their uncertainties
نویسندگان
چکیده
منابع مشابه
Determination of polarized parton distribution functions and their uncertainties
We investigate the polarized parton distribution functions (PDFs) and their uncertainties by using the world data on the spin asymmetry A1. The uncertainties of the polarized PDFs are estimated by the Hessian method. The up and down valence-quark distributions are determined well. However, the antiquark distributions have large uncertainties at this stage, and it is particularly difficult to fi...
متن کاملDetermination of polarized parton distribution functions
We study parametrization of polarized parton distribution functions in the αs leading order (LO) and in the next-to-leading order (NLO). From χ fitting to the experimental data on A1, optimum polarized distribution functions are determined. The quark spin content ∆Σ is very sensitive to the small-x behavior of antiquark distributions which suggests that small-x data are needed for precise deter...
متن کاملUncertainties of Parton Distribution Functions
High-energy particles interact through their quark and gluon constituents—the partons. By the asymptotic freedom of QCD, the parton cross sections may be approximated by perturbation theory. Then by the factorization theorem of QCD, the parton distribution functions of hadrons are the link between perturbative QCD and experimental measurements. This theory applies to a variety of high-energy pr...
متن کاملPolarized parton distribution functions reexamined.
The hard-gluonic contribution to the first moment of the polarized proton structure function g 1(x) is dependent of the factorization convention chosen in defining the quark spin density and the hard cross section for photon-gluon scattering. Two extremes of interest, namely gauge-invariant and chiral-invariant factorization schemes, are considered. We show that in order to satisfy the positivi...
متن کاملParametrization of polarized parton distribution functions
Polarized parton distribution functions are determined by using asymmetry A 1 data from longitudinally polarized deep inelastic scattering experiments. From our χ 2 analysis, polarized u-valence, d-valence, antiquark, and gluon distributions are obtained. We propose one set of leading-order distributions and two sets of next-to-leading-order ones as the longitudinally-polarized parton distribut...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2004
ISSN: 1550-7998,1550-2368
DOI: 10.1103/physrevd.69.054021