Heavy-quark mass dependence in global PDF analyses and 3- and 4-flavour parton distributions
Heavy-quark mass dependence in global PDF analyses and 3- and 4-flavour parton distributions
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DOI：
10.1140/epjc/s10052-010-1462-8
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发表时间：
2010-07
期刊：
影响因子：
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通讯作者：
A. Martin;W. Stirling;R. Thorne;G. Watt
中科院分区：
文献类型：
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作者：
A. Martin;W. Stirling;R. Thorne;G. Watt
我们研究了我们最近的MSTW 2008 NLO和NNLO PDF分析的魅力和底夸克质量的值的敏感性，我们提供了额外的公共PDF集的范围广泛的这些重夸克质量。我们量化的影响，在Tevatron和LHC的W，Z和希格斯生产的横截面上的变化。我们生成3-和4-味版本的（5-味）MSTW 2008 PDF通过演变输入PDF和α S确定从适合在5-味方案，包括特征向量PDF集必要的PDF不确定性计算。作为一个例子，他们的使用，我们研究的差异在Tevatron和LHC在4-和5-味方案的Z总截面。发现显着差异，说明需要通过使用5味方案恢复大的样本。然而，如果对关联（大质量）b夸克进行切割，就像实验测量产生和类似过程一样，4味方案仍然是必要的。
We study the sensitivity of our recent MSTW 2008 NLO and NNLO PDF analyses to the values of the charm- and bottom-quark masses, and we provide additional public PDF sets for a wide range of these heavy-quark masses. We quantify the impact of varyingmcandmbon the cross sections forW,Zand Higgs production at the Tevatron and the LHC. We generate 3- and 4-flavour versions of the (5-flavour) MSTW 2008 PDFs by evolving the input PDFs andαSdetermined from fits in the 5-flavour scheme, including the eigenvector PDF sets necessary for calculation of PDF uncertainties. As an example of their use, we study the difference in theZtotal cross sections at the Tevatron and LHC in the 4- and 5-flavour schemes. Significant differences are found, illustrating the need to resum large logarithms inby using the 5-flavour scheme. The 4-flavour scheme is still necessary, however, if cuts are imposed on associated (massive)b-quarks, as is the case for the experimental measurement ofproduction and similar processes.