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arXiv 0709.3038hep-phhep-exnucl-exnucl-th
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核部分子分布函数的确定及其次领先阶的不确定性

Determination of nuclear parton distribution functions and their uncertainties at next-to-leading order

M. Hirai, S. Kumano, T. -H. Nagai

备注：
15 pages, LaTeX, 22 eps files, to appear in PRC. A code for calculating our nuclear parton distribution functions and their uncertainties can be obtained from http://research.kek.jp/people/kumanos/nuclp.html
发表信息：
Phys.Rev.C76:065207,2007
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摘要：

核部分子分布函数（NPDFs）是通过对结构-功能比F_2 ^A/F_2^{A '}和Drell-Yan截面比σ_{DY}^A/σ_{DY}^{A'}的实验数据进行全局分析而确定的。分析了运行耦合常数α s的首阶（LO）和次首阶（NLO）。在LO和NLO中估计NPDF的不确定性，以找到可能的NLO改进。价夸克分布被很好地确定，反夸克分布也在x<0.1时被确定。然而，反夸克分布在x>0.2时有很大的不确定性。在这个阶段无法修复胶子修饰。与LO分析相比，NLO分析的优点在于对胶子分布的敏感性，但在LO和NLO中胶子的不确定性几乎相同。这是因为目前的标度破坏数据不够精确，无法确定精确的核胶子分布。通过分析质子-氘核比F_2^D/F_2^p的数据，讨论了氘核中PDF的修改。提供了一个代码，用于计算LO和NLO中给定x和Q^2时的NPDF及其不确定度。

英文摘要：

Nuclear parton distribution functions (NPDFs) are determined by global analyses of experimental data on structure-function ratios F_2^A/F_2^{A'} and Drell-Yan cross-section ratios σ_{DY}^A/σ_{DY}^{A'}. The analyses are done in the leading order (LO) and next-to-leading order (NLO) of running coupling constant α_s. Uncertainties of the NPDFs are estimated in both LO and NLO for finding possible NLO improvement. Valence-quark distributions are well determined, and antiquark distributions are also determined at x<0.1. However, the antiquark distributions have large uncertainties at x>0.2. Gluon modifications cannot be fixed at this stage. Although the advantage of the NLO analysis, in comparison with the LO one, is generally the sensitivity to the gluon distributions, gluon uncertainties are almost the same in the LO and NLO. It is because current scaling-violation data are not accurate enough to determine precise nuclear gluon distributions. Modifications of the PDFs in the deuteron are also discussed by including data on the proton-deuteron ratio F_2^D/F_2^p in the analysis. A code is provided for calculating the NPDFs and their uncertainties at given x and Q^2 in the LO and NLO.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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