xFitter中DIS PDF拟合的求和标度效应
Resummation-scale effects in DIS PDF fits with xFitter
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中文总结 AI 辅助
本文研究xFitter框架下NNLO DIS PDF拟合中求和标度变化的影响，发现低标度下对胶子和海夸克PDF偏移显著，提高起始标度和虚度截断可减小效应。
中文摘要 AI 辅助
重正化群演化通过跑动耦合和劈裂函数进入PDF确定。在固定微扰阶下，演化方程的解在名义精度之外并非唯一，这种残余自由度可以通过求和标度变化来探测。本文总结了使用xFitter拟合框架进行的包含HERA DIS数据的NNLO研究中该效应的结果。在低标度基线拟合中，引起的偏移很大，尤其是对胶子和海夸克PDF，并可能以百分之几的水平影响LHC和FCC的顶夸克对预测。提高PDF起始标度并施加更高的DIS虚度截断可显著减小该效应，这一结论也得到将求和标度视为由数据直接约束的自由参数的支持。
英文摘要
Renormalisation-group evolution enters PDF determinations through the running coupling and the splitting functions. At fixed perturbative order, the solution of the evolution equations is not unique beyond the nominal accuracy, and this residual freedom can be probed through resummation-scale variations. This contribution summarises an NNLO study of this effect in inclusive HERA DIS fits performed with the xFitter fitting framework. The induced shifts are sizeable in a low-scale baseline fit, especially for the gluon and sea PDFs, and can affect LHC and FCC top-quark pair predictions at the few-percent level. Raising the PDF starting scale and applying a higher DIS virtuality cut considerably reduces the effect, a conclusion also supported by treating the resummation scale as a free parameter constrained directly by the data.
发表机构
- Università degli Studi Link（Link大学）
- INFN Sezione di Roma Tor Vergata（罗马托维尔塔INFN分部）
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