# Determining the strong coupling: status and challenges

Antonio Pich, Juan Rojo, Rainer Sommer, Antonio Vairo

### Abstract

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 language English arXiv.org Published - 28 Nov 2018

### Fingerprint

quantum chromodynamics
partons
leptons
bosons
distribution functions
quarks
energy
decay

### 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

### Cite this

Pich, Antonio ; Rojo, Juan ; Sommer, Rainer ; Vairo, Antonio. / Determining the strong coupling : status and challenges. In: arXiv.org. 2018.
title = "Determining the strong coupling: status and challenges",
abstract = "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.",
keywords = "hep-ph, hep-ex, hep-lat",
author = "Antonio Pich and Juan Rojo and Rainer Sommer and Antonio Vairo",
note = "Round Table Discussion at the XIIIth Quark Confinement and the Hadron Spectrum conference. 32 pages, 11 figures. Added references",
year = "2018",
month = "11",
day = "28",
language = "English",
journal = "arXiv.org",
issn = "2331-8422",

}

Determining the strong coupling : status and challenges. / Pich, Antonio; Rojo, Juan; Sommer, Rainer; Vairo, Antonio.

In: arXiv.org, 28.11.2018.

TY - JOUR

T1 - Determining the strong coupling

T2 - status and challenges

AU - Pich, Antonio

AU - Rojo, Juan

AU - Sommer, Rainer

AU - Vairo, Antonio

N1 - Round Table Discussion at the XIIIth Quark Confinement and the Hadron Spectrum conference. 32 pages, 11 figures. Added references

PY - 2018/11/28

Y1 - 2018/11/28

N2 - 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.

AB - 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.

KW - hep-ph

KW - hep-ex

KW - hep-lat

M3 - Article

JO - arXiv.org

JF - arXiv.org

SN - 2331-8422

ER -