An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties
Abstract This paper presents a computer code for analyzing electroweak precision data (EWPD) in the framework of the Standard Model Effective Field Theory (SMEFT), highlights the importance of recent ATLAS and CMS precision measurements, and introduces a novel analysis of the forward–backward asymme...
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| Language: | English |
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2025-07-01
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| Series: | Journal of High Energy Physics |
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| Online Access: | https://doi.org/10.1007/JHEP07(2025)089 |
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| author | Hannes Mildner |
| author_facet | Hannes Mildner |
| author_sort | Hannes Mildner |
| collection | DOAJ |
| description | Abstract This paper presents a computer code for analyzing electroweak precision data (EWPD) in the framework of the Standard Model Effective Field Theory (SMEFT), highlights the importance of recent ATLAS and CMS precision measurements, and introduces a novel analysis of the forward–backward asymmetry at the LHC. The computer code provides the likelihood of SMEFT Wilson coefficients based on precision measurements of W and Z pole observables, interpolation formulas for Standard Model predictions, and modular SMEFT parametrizations. SMEFT predictions including next-to-leading-order (NLO) effects in perturbative and SMEFT expansion are available and five alternative electroweak input parameter schemes are supported. The likelihood addresses shortcomings of previous formulations in the treatment of parametric uncertainties and can be straightforwardly included in SMEFT fits of LHC data. The input parameter scheme dependence and role of NLO corrections is studied for the EWPD fit in the SMEFT. Furthermore, the impact of recent ATLAS and CMS measurements — of the W boson mass and width, of the lepton flavour universality (LFU) of W branching fractions, and the effective leptonic weak mixing angle, sin 2 θ eff ℓ $$ {\sin}^2{\theta}_{\textrm{eff}}^{\ell } $$ — is analyzed. A test of LFU that surpasses the precision of existing measurements is proposed based on the sin 2 θ eff ℓ $$ {\sin}^2{\theta}_{\textrm{eff}}^{\ell } $$ measurement. Finally, an ATLAS Drell-Yan triple-differential cross-section measurement is reinterpreted in the SMEFT and combined with the EWPD likelihood. This analysis demonstrates the feasibility of the LFU precision test, improves constraints on muon couplings with respect to the world average, and determines a combination of the quark-coupling asymmetry parameters A u and A d with a precision comparable to that of the heavy flavour parameters A c and A b . |
| format | Article |
| id | doaj-art-60cd02c51c6540a4a67c3768997f88ae |
| institution | Kabale University |
| issn | 1029-8479 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj-art-60cd02c51c6540a4a67c3768997f88ae2025-08-20T04:01:42ZengSpringerOpenJournal of High Energy Physics1029-84792025-07-012025714610.1007/JHEP07(2025)089An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson propertiesHannes Mildner0Institut für Physik, Johannes Gutenberg-Universität MainzAbstract This paper presents a computer code for analyzing electroweak precision data (EWPD) in the framework of the Standard Model Effective Field Theory (SMEFT), highlights the importance of recent ATLAS and CMS precision measurements, and introduces a novel analysis of the forward–backward asymmetry at the LHC. The computer code provides the likelihood of SMEFT Wilson coefficients based on precision measurements of W and Z pole observables, interpolation formulas for Standard Model predictions, and modular SMEFT parametrizations. SMEFT predictions including next-to-leading-order (NLO) effects in perturbative and SMEFT expansion are available and five alternative electroweak input parameter schemes are supported. The likelihood addresses shortcomings of previous formulations in the treatment of parametric uncertainties and can be straightforwardly included in SMEFT fits of LHC data. The input parameter scheme dependence and role of NLO corrections is studied for the EWPD fit in the SMEFT. Furthermore, the impact of recent ATLAS and CMS measurements — of the W boson mass and width, of the lepton flavour universality (LFU) of W branching fractions, and the effective leptonic weak mixing angle, sin 2 θ eff ℓ $$ {\sin}^2{\theta}_{\textrm{eff}}^{\ell } $$ — is analyzed. A test of LFU that surpasses the precision of existing measurements is proposed based on the sin 2 θ eff ℓ $$ {\sin}^2{\theta}_{\textrm{eff}}^{\ell } $$ measurement. Finally, an ATLAS Drell-Yan triple-differential cross-section measurement is reinterpreted in the SMEFT and combined with the EWPD likelihood. This analysis demonstrates the feasibility of the LFU precision test, improves constraints on muon couplings with respect to the world average, and determines a combination of the quark-coupling asymmetry parameters A u and A d with a precision comparable to that of the heavy flavour parameters A c and A b .https://doi.org/10.1007/JHEP07(2025)089SMEFTElectroweak Precision Physics |
| spellingShingle | Hannes Mildner An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties Journal of High Energy Physics SMEFT Electroweak Precision Physics |
| title | An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties |
| title_full | An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties |
| title_fullStr | An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties |
| title_full_unstemmed | An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties |
| title_short | An EWPD SMEFT likelihood for the LHC — and how to improve it with measurements of W and Z boson properties |
| title_sort | ewpd smeft likelihood for the lhc and how to improve it with measurements of w and z boson properties |
| topic | SMEFT Electroweak Precision Physics |
| url | https://doi.org/10.1007/JHEP07(2025)089 |
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