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Main Authors: Li, Xu, Yan, Bin, Yuan, C. -P.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.04069
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author Li, Xu
Yan, Bin
Yuan, C. -P.
author_facet Li, Xu
Yan, Bin
Yuan, C. -P.
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04069
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Lam-Tung relation breaking in $Z$ boson production as a probe of SMEFT effects
Li, Xu
Yan, Bin
Yuan, C. -P.
High Energy Physics - Phenomenology
High Energy Physics - Experiment
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.
title Lam-Tung relation breaking in $Z$ boson production as a probe of SMEFT effects
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2405.04069