发表机构
Institute of Nuclear Physics Polish Academy of Sciences; State Key Laboratory of Nuclear Physics and Technology, Institute of Quantum Matter, South China Normal University; Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Nuclear Science（波兰科学院核物理研究所; 华南大学量子物质研究所核物理与技术国家重点实验室; 广东省基础研究中心物质结构与基本相互作用卓越中心广东省核科学重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文将非极点技术扩展至$pp$碰撞的 twist-3 胶子分布贡献，解决了此前该方法无法复现$pp$碰撞 Sivers 效应已知结果的问题，为任意过程的 Sivers 效应提供了可行的非极点计算方案。
AI 中文摘要
已知在共线因子化框架内，Sivers 效应被描述为 twist-3 效应，其特征在于源于硬部分子散射中的极点贡献。仅聚焦于极点部分的计算形式体系于2000年代建立，且已对$ep$和$pp$碰撞中的诸多过程计算了单自旋不对称性（SSAs）。另一方面，还存在被视为 Collins 效应的 twist-3 碎裂函数的贡献，Collins 效应源于硬散射的非极点部分，其计算形式体系与 Sivers 效应的计算方式略有不同。近年来，已有一些尝试通过应用为 Collins 效应开发的“非极点”形式体系来重新研究 Sivers 效应，对于$ep$碰撞，该方法已成功复现已知结果；然而对于$pp$碰撞，初始态相互作用和末态相互作用的共存使得计算更为复杂，尚未复现已知结果。本文针对该问题提供了一种解决方案，开发了非极点方法，使其可应用于任意过程中的 Sivers 效应。
英文摘要
It is known that the Sivers effect is described as a twist-3 effect within the collinear factorization framework and has the characteristic feature that it arises from the pole contribution in a hard parton scattering. The calculation formalism that focuses only on the pole part was established in the 2000s and SSAs were calculated for many processes in $ep$ and $pp$ collisions. On the other hand, there also exists a contribution from twist-3 fragmentation functions regarded as the Collins effect. The Collins effect arises from the nonpole part of the hard scattering and its calculation is formulated in a somewhat different manner from that for the Sivers effect. In recent years, some attempts have been made to revisit the Sivers effect by applying the ``nonpole'' formalism developed for the Collins effect. For $ep$ collisions, this approach has successfully reproduced the known results. For $pp$ collisions, however, the presence of both initial-state-interaction and final-state-interaction makes the calculation more complicated and the known results have not yet been reproduced. In this paper, we provide a solution to this problem and develop the nonpole method so that it can be applied to the Sivers effect in any process.
Comments22 pages, 5 figures
