论文标题
从$ w^\ pm $生产p+pb碰撞中提取核PDF的质子-PDF不确定性
Proton-PDF uncertainties in extracting nuclear PDFs from $W^\pm$ production in p+Pb collisions
论文作者
论文摘要
我们讨论了$ w^\ pm $ boson在P+PB碰撞中的CMS合作测量在8.16 TEV中的核部分分配功能（PDFS）的约束。通过使用理论协方差 - 矩阵方法和HESSIAN PDF重新加权来量化自由蛋白PDF不确定性对核PDF提取的影响。我们讨论了减轻这些理论不确定性的不同方法，包括自我归一化，前后比率和核修饰比。发现这些方法都没有提供完美的取消对自由蛋白PDF的完美取消，但是，由于目前的数据不确定性，对于全球分析而言，剩余的free-PROTON-PDF依赖性方便，对核修饰的提取的影响很小。基于对LHC运行3的可获得统计数据的简单估计，我们认为这将在不久的将来发生变化，并且相应地传播质子PDF的不确定性变得越来越重要。使用有关自由蛋白不确定性相关性的获得的信息，我们还确定了一个新的电荷不对称比率，其中发现质子-PDF不确定性的取消非常好。
We discuss the recent CMS Collaboration measurement of $W^\pm$ boson production in p+Pb collisions at 8.16 TeV in terms of the constraining power on nuclear parton distribution functions (PDFs). The impact of the free-proton PDF uncertainties on the nuclear PDF extraction is quantified by using a theoretical covariance-matrix method and Hessian PDF reweighting. We discuss different ways to mitigate these theoretical uncertainties, including self-normalization, forward-to-backward ratios and nuclear-modification ratios. It is found that none of these methods offer perfect cancellation of the free-proton PDFs but, with the present data uncertainties, the residual free-proton-PDF dependence has, conveniently for the global analyses, little effect on the extraction of the nuclear modifications. Based on a simple estimate of obtainable statistics at the LHC Run 3, we argue that this will change in the near future and it becomes more important to propagate the proton-PDF uncertainties accordingly. Using the obtained information on the correlations of the free-proton uncertainties, we also identify a new charge asymmetry ratio, where the cancellation of the proton-PDF uncertainties is found to be extremely good.
