关联 $W$ 玻色子与粲夸克产生：对部分子分布函数分析的启示
Associated $W$ + charm production: indications for PDF analysis
AI总结：
该研究在次领头阶计算了 $W$ 玻色子与粲介子联合产生过程，通过比较电荷相反事件比率与ATLAS数据，发现CT18ANLO（奇异数不对称性为零）与数据吻合，而MSHT20NLO和NNPDF4.0NLO的张力源于奇异数不对称性过大。
AI中文摘要：
与其它轻夸克相比，质子中的奇异夸克和反奇异夸克含量仍受到较弱的约束，尤其是两者之间的不对称性。与粲介子 $D^{(*)\pm}$ 联合产生的 $W^\mp$ 玻色子可为未来部分子分布函数的拟合提供额外约束。我们在一般质量变味数方案中，于微扰量子色动力学次领头阶计算了这一过程。我们研究了电荷相反的 $W$ 玻色子事件之间的产生比率，在该比率中各种理论不确定性大幅抵消，而对部分子分布函数的敏感性仍然保留。我们将此量的预测与近期 $\n\sqrt{s} = 13$ TeV 的 ATLAS 数据进行比较，发现将奇异数不对称性设为零的 CT18ANLO 与数据吻合良好，而在相关动量分数 $x$ 范围内具有正奇异数不对称性的 MSHT20NLO 和 NNPDF4.0NLO 与数据存在更多张力。对该产生比率的近似部分子分布函数级别分析表明，这种张力可能归因于过大的奇异数不对称性。
英文摘要：
The strange quark and antiquark contents of the proton remain weakly constrained compared to the other light quarks, particularly the asymmetry between the two. Production of a $W^\mp$ boson in association with a charmed meson $D^{(*)\pm}$ could provide additional constraints in future fits of parton distribution functions. We calculate this process in general-mass variable-flavor-number scheme at next-to-leading order in perturbative Quantum Chromodynamics. We investigate the production ratio between events with oppositely charged $W$ bosons, in which various theoretical uncertainties largely cancel while sensitivity to PDFs remains. We compare our predictions for this quantity with the recent ATLAS data at $\sqrt{s} = 13$ TeV and find that CT18ANLO, which sets the strangeness asymmetry to zero, yields good agreement with the data while MSHT20NLO and NNPDF4.0NLO, which have positive strangeness asymmetry in the relevant range of momentum fraction $x$, show more tension with the data. An approximate PDF-level analysis of the production ratio indicates that this tension could be attributed to a too large strangeness asymmetry.
