The kaon parton distribution functions (PDFs) are poorly known due to paucity of kaon-induced Drell-Yan data. Nevertheless, these Drell-Yan data suggest a softer valence quark distribution of the kaon compared to that of the pion. We discuss the opportunity to constrain the kaon PDFs utilizing the existing kaon-induced production data. We compare the and cross-section ratio data with calculations based on two global-fit parametrizations and two recent theoretical predictions for the kaon and pion PDFs, and test the results with two quarkonium production models. The cross-section ratio for production provides independent evidence of different valence quark distributions in pion and kaon. The data are found to be sensitive to the gluon distribution in kaon. We show that these production data provide valuable constraints for evaluating the adequacy of currently available sets of kaon PDFs.

中文翻译：

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约束来自 Drell-Yan 和 J/ψ 生产的 kaon PDF


由于缺乏 kaon 诱导的 Drell-Yan 数据，人们对 kaon 部分顿分布函数 (PDF) 知之甚少。然而，这些 Drell-Yan 数据表明 kaon 的价夸克分布比 π 介子的分布更软。我们讨论了利用现有 kaon 诱导的生产数据来约束 kaon PDF 的机会。我们将 和 截面比数据与基于两个全局拟合参数化和两个最近的 kaon 和 pion PDF 理论预测的计算进行比较，并使用两个夸克素生产模型测试结果。产生的横截面比提供了π介子和Kaon中不同价夸克分布的独立证据。发现数据对 kaon 中的胶子分布敏感。我们表明，这些生产数据为评估当前可用的 kaon PDF 集的充分性提供了有价值的约束。