Determining the strong coupling: status and challenges

Antonio Pich, Juan Rojo, Rainer Sommer, Antonio Vairo

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The `XIIIth Quark Confinement and the Hadron Spectrum' conference (Confinement 2018) contained a `Round Table Discussion' on the status of the determinations of the strong coupling $\alpha_s(m_Z)$ as well as prospects for future improvements. In this contribution, we summarize the different aspects of the discussion. In particular, we cover $\alpha_s$ determinations from inclusive observables, such as the hadronic decays of the $Z$ boson and the $\tau$ lepton; from global fits of parton distribution functions (PDFs); from high-energy collider observables, and from event shapes; as well as from various observables computed by lattice QCD, specifically from the QCD static energy. There is overall good agreement between these various determinations, but there are also outliers, differing from the world average by up to $-5\%$. Nevertheless, the general agreement constitutes a beautiful and significant test of the detailed nature of the strong interactions, and provides a crucial input for high-precision calculations in QCD and beyond.
Original languageEnglish
Article number035
Pages (from-to)0-32
Number of pages33
JournalProceedings of Science
Publication statusPublished - 28 Nov 2018
EventXXIIIth Quark Confinement and the Hadron Spectrum conference: 1-6 August 2018, University of Maynooth, Ireland - Maynooth, Ireland
Duration: 1 Aug 20186 Aug 2018
Conference number: 23th

Bibliographical note

Round Table Discussion at the XIIIth Quark Confinement and the Hadron Spectrum conference. 32 pages, 11 figures. Added references


  • hep-ph
  • hep-ex
  • hep-lat


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