We present a phenomenological analysis of the \(q_{\text {T}}\)-weighted transverse spin dependent azimuthal asymmetry recently measured by the COMPASS Collaboration in polarized pion-proton Drell–Yan process. In the kinematical regimes explored by experiments, we consider the leading-twist contributions from the Boer–Mulders distribution functions \(h_{1}^{\perp }(x,k_{\text {T}}^{2})\) of both the pion and the proton, the transversity distribution \(h_{1}(x,k_{\text {T}}^{2})\) and the pretzelosity distribution \(h_{1\text {T}}^{\perp }(x,k_{\text {T}}^{2})\) of the proton, with the unpolarized transverse-momentum-dependent distribution function \(f_{1}(x,k_{\text {T}}^{2})\) of the proton being also involved in the calculation. By comparing the data reported by the COMPASS Collaboration with theoretical calculated results, we find that the COMPASS measurements represent the first experimental evidence of the Boer–Mulders effect in polarized Drell–Yan process. We also test the universality between proton and pion Boer–Mulders functions.

我们提出了最近由 COMPASS Collaboration 在极化 pion-proton Drell-Yan 过程中测量的\(q_{\text {T}}\)加权横向自旋相关方位角不对称性的现象学分析。在实验探索的运动学机制中，我们考虑了 Boer-Mulders 分布函数\(h_{1}^{\perp }(x,k_{\text {T}}^{2})\ )的介子和质子，横向分布\(h_{1}(x,k_{\text {T}}^{2})\)和脆性分布\(h_{1\text {T} }^{\perp }(x,k_{\text {T}}^{2})\)的质子，具有非极化横向动量相关分布函数\(f_{1}(x,k_{\文本 {T}}^{2})\)质子也参与计算。通过比较 COMPASS Collaboration 报告的数据与理论计算结果，我们发现 COMPASS 测量代表了极化 Drell-Yan 过程中 Boer-Mulders 效应的第一个实验证据。我们还测试了质子和 pion Boer-Mulders 函数之间的通用性。