The strong coupling constant: state of the art and the decade ahead

d'Enterria, D.; Reichelt, Daniel; others

Abstract

Theoretical predictions for particle production cross sections and decays at colliders rely heavily on perturbative Quantum Chromodynamics (QCD) calculations, expressed as an expansion in powers of the strong coupling constant α S . The current O(1%) uncertainty of the QCD coupling evaluated at the reference Z boson mass, αS(mZ2)=0.1179±0.0009 , is one of the limiting factors to more precisely describe multiple processes at current and future colliders. A reduction of this uncertainty is thus a prerequisite to perform precision tests of the Standard Model as well as searches for new physics. This report provides a comprehensive summary of the state-of-the-art, challenges, and prospects in the experimental and theoretical study of the strong coupling. The current αS(mZ2) world average is derived from a combination of seven categories of observables: (i) lattice QCD, (ii) hadronic τ decays, (iii) deep-inelastic scattering and parton distribution functions fits, (iv) electroweak boson decays, hadronic final-states in (v) e+e−, (vi) e–p, and (vii) p–p collisions, and (viii) quarkonia decays and masses. We review the current status of each of these seven αS(mZ2) extraction methods, discuss novel α S determinations, and examine the averaging method used to obtain the world-average value. Each of the methods discussed provides a ‘wish list’ of experimental and theoretical developments required in order to achieve the goal of a per-mille precision on αS(mZ2) within the next decade.

Citation

d’Enterria, D., d'Enterria, D., Kluth, S., Reichelt, D., Zanderighi, G., others, Ayala, C., Benitez-Rathgeb, M. A., Blümlein, J., Boito, D., Brambilla, N., Britzger, D., Camarda, S., Cooper-Sarkar, A. M., Cridge, T., Cvetič, G., d’Enterria, D., Dalla Brida, M., Deur, A., Giuli, F., …Xie, K. (2024). The strong coupling constant: state of the art and the decade ahead. Journal of Physics G: Nuclear and Particle Physics, 51(9), Article 090501. https://doi.org/10.1088/1361-6471/ad1a78

• Journal Article Type: Article
• Acceptance Date: Jan 3, 2024
• Online Publication Date: Oct 28, 2024
• Publication Date: Sep 1, 2024
• Deposit Date: Jul 28, 2022
• Publicly Available Date: Nov 7, 2024
• Journal: Journal of Physics G: Nuclear and Particle Physics
• Print ISSN: 0954-3899
• Electronic ISSN: 1361-6471
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 51
• Issue: 9
• Article Number: 090501
• DOI: https://doi.org/10.1088/1361-6471/ad1a78
• Keywords: QCD, colliders, strong coupling
• Public URL: https://durham-repository.worktribe.com/output/1196663