# Determination of the strong coupling constant $\alpha_s(m_Z)$ from measurements of the total cross section for top-antitop quark production

Abstract : We present a determination of the strong coupling constant $\alpha _s \left( m_Z \right)$ using inclusive top-quark pair production cross section measurements performed at the LHC and at the Tevatron. Following a procedure first applied by the CMS Collaboration, we extract individual values of $\alpha _s \left( m_Z \right)$ from measurements by different experiments at several centre-of-mass energies, using QCD predictions complete in NNLO perturbation theory, supplemented with NNLL approximations to all orders, and suitable sets of parton distribution functions. The determinations are then combined using a likelihood-based approach, where special emphasis is put on a consistent treatment of theoretical uncertainties and of correlations between various sources of systematic uncertainties. Our final combined result is $\alpha _s \left( m_Z \right) =0.1177^{+0.0034{}}_{-0.0036{}}$ .
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Eur.Phys.J.C, 2017, 77 (11), pp.778. 〈10.1140/epjc/s10052-017-5340-5〉
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https://hal.archives-ouvertes.fr/hal-01669739
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Soumis le : jeudi 21 décembre 2017 - 00:18:08
Dernière modification le : mardi 17 avril 2018 - 03:00:07

### Citation

Thomas Klijnsma, Siegfried Bethke, Günther Dissertori, Gavin Salam. Determination of the strong coupling constant $\alpha_s(m_Z)$ from measurements of the total cross section for top-antitop quark production. Eur.Phys.J.C, 2017, 77 (11), pp.778. 〈10.1140/epjc/s10052-017-5340-5〉. 〈hal-01669739〉

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