Year: 2026
Type: preprint
Abstract: The strong coupling constant $α_s$ is a fundamental parameter of the Standard Model. Its precise determination is essential for accurately predicting, studying, and understanding processes at the Large Hadron Collider and future experiments such as the Future Circular Collider. Event shape and correlator observables measured at electron-positron colliders provide one of the cleanest environments for extracting $α_s$, thanks to their sensitivity to $α_s$ and the availability of high-precision data from the Large Electron-Positron Collider. More broadly, such observables provide an ideal setting to develop and test our understanding of the perturbative and non-perturbative elements of Quantum Chromodynamics, which will underpin the field's precision and discovery frontiers for decades to come. Despite these advances, significant discrepancies persist between different determinations of $α_s$ from event shapes, both in the extracted central values and estimated uncertainties. This document motivates the establishment of a dedicated Task Force to coordinate a community-wide effort addressing these open questions. We report on the first two-day meeting held at CERN in November 2025, summarizing the scientific discussion and documenting the experimental analyses identified as priorities during the meeting, as well as the concrete list of tasks to be carried out by the theory community in preparation for future meetings.
Source: arXiv (Cornell University)
Authors: Badea, Anthony, Buonocore, Luca, Vita, Gherardo, Alioli, Simone, Capatti, Zeno, Chen, Yi, d'Enterria, David, Gehrmann, Thomas, Hoang, Andre H., Huss, Alexander, Jaskiewicz, Sebastian, Karlberg, Alexander, Lee, Yen-Jie, Mangano, Michelangelo L., Mateu, Vicent, Miao, Jiahao, Monni, Pier Francesco, Nason, Paolo, Rottoli, Luca, Stewart, Iain W., Torrielli, Paolo, Zanderighi, Giulia
Institutions: University of Chicago, European Organization for Nuclear Research, Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca, University of Milano-Bicocca, University of Bern, Vanderbilt University, University of Zurich, University of Vienna, Max Planck Institute for Physics, Massachusetts Institute of Technology, Universidad de Salamanca, University of Milan, Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Fisica Nucleare, Sezione di Torino, University of Turin, Technical University of Munich
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7208714415
Cites:
Cited by:
Related to: