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arXiv 2405.04069hep-phhep-ex
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Z玻色子产生中的Lam-Tung关系破坏作为SMEFT效应的探针

Lam-Tung relation breaking in $Z$ boson production as a probe of SMEFT effects

Xu Li, Bin Yan, C. -P. Yuan

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6 pages, 5 figures, published version in PRD
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AI总结：

针对LHC上Drell-Yan过程高$p_T^{\ell\ell}$区域Lam-Tung关系与标准模型预测的长期差异，本文在SMEFT框架下通过模型无关分析发现6维Z玻色子偶极算符二次效应主导破坏，为差异提供解释并可约束相关新物理。

摘要：

大型强子对撞机（LHC）上Drell-Yan过程的高$p_T^{\ell\ell}$区域中Lam-Tung关系的破坏，与标准模型在$\mathcal{O}(α_s^3)$精度下的预测存在长期差异。本文采用模型无关分析，在标准模型有效场论（SMEFT）框架内研究这一现象。结果表明，SMEFT对该破坏的主导贡献出现在$1/Λ^4$阶，量子色动力学（QCD）相互作用精度为$\mathcal{O}(α_s)$。值得注意的是，我们证明了与Z玻色子相关的6维偶极算符的二次效应主导了各种6维和8维算符引起的破坏效应。这为LHC上观测到的与标准模型预测的差异提供了可能的解释。此外，这种破坏效应还可作为约束Z玻色子偶极相互作用的有力工具，突显了它们在Drell-Yan过程中新物理潜在来源中的重要性。

英文摘要：

The violation of Lam-Tung relation in the high-$p_T^{\ell\ell}$ region of the Drell-Yan process at the LHC presents a long-standing discrepancy with the standard model prediction at $\mathcal{O}(α_s^3)$ accuracy. In this Letter, we employed a model-independent analysis to investigate this phenomenon within the framework of the Standard Model Effective Field Theory (SMEFT). Our findings revealed that the leading contributions from SMEFT to this violation appear at the $1/Λ^4$ order with $\mathcal{O}(α_s)$ accuracy in QCD interaction. Notably, we demonstrated that the quadratic effect of dimension-6 dipole operators, associated with the $Z$ boson, dominates the breaking effects induced by various dimension-6 and dimension-8 operators. This provides a possible explanation for the observed discrepancy with the Standard Model predictions at the LHC. Furthermore, the breaking effects could also serve as a powerful tool for constraining $Z$-boson dipole interactions, highlighting their importance among potential sources of new physics in the Drell-Yan process.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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