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arXiv · 1708.07495

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

Thomas Klijnsma·Siegfried Bethke·Günther Dissertori·Gavin P. Salam
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Abstract

We present a determination of the strong coupling constant $α_s(m_Z)$ 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 $α_s(m_Z)$ 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 $α_s(m_Z) = 0.1177^{+0.0034}_{-0.0036}$.

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Thomas Klijnsma, Siegfried Bethke, Günther Dissertori, Gavin P. Salam. 2017-10-30. Determination of the strong coupling constant $α_s(m_Z)$ from measurements of the total cross section for top-antitop quark production. https://doi.org/10.1140/epjc%2Fs10052-017-5340-5

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