alphas-2025: Workshop on precision measurements of the QCD coupling constant

14 Dec 2025, 18:00 → 19 Dec 2025, 14:00 Europe/Zurich

David d'Enterria (CERN), Giulia Zanderighi (Max Planck Society (DE)), Stefan Kluth (Max Planck Society (DE))

The "alphas-2025: Workshop on precision measurements of the strong coupling constant" will be held at the CNRS Paul Langevin Center in Aussois (Savoie) in the third week of December 2025: Mon. 15th to Friday 19th (in-person participants should expect to arrive on Sun. 14th afternoon, dinner will be served. The workshop will end at noon on Friday 19th, lunch will be served).

The workshop aims at exploring in depth the current status and upcoming prospects in the determination of the QCD coupling constant $\alpha_S(m_Z)$ from the key observables where high-precision experimental measurements and theoretical calculations are (or will be) available: (i) lattice QCD, (ii) hadronic decays of tau leptons, (iii) deep-inelastic electron-proton scattering and global parton densities analyses, (iv) QCD corrections to electroweak precision observables, and analysis of (v) hadronic final states in high energy particle collisions ($e^+e^-$, ep, and pp). 

Previous meetings:

• alpha_s(2024), ECT*, Trento. Proceedings: J.Phys.G 51 (2024) 090501 [arXiv:2203.08271]
• alpha_s(2022), ECT*, Trento.
• alpha_s(2019), ECT*, Trento. Proceedings: arXiv:1907.01435
• alpha_s(2015), CERN, Geneva. Proceedings: arXiv:1512.05194
• alpha_s(2011), MPI, Munich. Proceedings: arXiv:1110.0016

 

Sunday 14 December

19:00 Dinner

Monday 15 December

08:45 Welcome/Introduction

alpha_s: Lattice QCD

1 alphas from LatticeQCD

Speaker: Alberto Ramos Martinez (Univ. of Valencia and CSIC (ES))

2 FLAG update (to be confirmed)

Speaker: Stefan Sint (Trinity College Dublin)

10:00 Coffee break

alpha_s: Lattice QCD

3 Strong coupling constant from the static energy

Speaker: Alexei Bazavov (Michigan State University)

4 A precise $alpha_s$ determination from the R-improved QCD Static Energy

Speaker: José Manuel Mena Valle (Universidad de Salamanca)

5 Discussion: alpha_s from lattice QCD

12:00 Lunch and free afternoon (ski)

alpha_s from quarkonia

6 Determination of the quark masses and the strong coupling from global fits to quarkonium at N3LO

Speaker: Prof. VICENT Mateu (University of Salamanca)

alpha_s from DIS & PDFs

7 A Determination of alphas( mZ ) at aN3LO_QCD​ ⊗NLO_QED ​Accuracy from a Global PDF Analysis

Speakers: Emanuele Roberto Nocera, Emanuele Roberto Nocera (Università degli Studi di Torino and INFN Torino), Juan Rojo Chacon (Nikhef National institute for subatomic physics (NL))

8 MSHT Approximate N3LO Determination of the Strong Coupling Constant (Updates)

Speaker: Thomas Cridge

9 alpha_s from the CT25 global PDF fit

Speakers: Joey Huston (Department of Physics and Astronomy), Joey Huston (Michigan State University (US)), Kirtimaan Ajaykant Mohan, Prof. Pavel Nadolsky (Michigan State University)

19:00 Dinner

Tuesday 16 December

alpha_s from DIS & PDFs

10 Complete 3-loop heavy-flavor corrections for unpolarized & polarized structure functions

Speaker: Prof. Johannes Bluemlein

11 alpha_s from DY and top quark data at hadron colliders

Speakers: Sven-Olaf Moch (Hamburg University (DE)), Sven-Olaf Moch

10:00 Coffee break

alpha_s from DIS & PDFs

12 alpha_s at EIC

Speaker: Zuhal Seyma Demiroglu (Stony Brook University)

13 αs from large-x DIS resummation

Speaker: Анатолий Котиков

14 alpha_s measurement prospects at the EIC and JLab@22

Speaker: Alexandre Deur (Jefferson Lab)

12:00 Lunch / Ski

alpha_s at hadron colliders

15 Determination of the strong coupling and its running from measurements of inclusive jet production at CMS

Speaker: Valentina Guglielmi (University of Zurich (CH))

16 CMS extractions of the strong coupling constant: Status and plans

Speaker: Patrick Louis S Connor (CERN)

17 Recent ATLAS determinations of the strong coupling constant

Speaker: Prof. Claudia Glasman (Universidad Autonoma de Madrid (ES))

18 Precise Determination of the Strong Coupling Constant from Dijet Cross Sections up to the Multi-TeV Range

Speaker: Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE))

19:00 Dinner

Wednesday 17 December

alpha_s at hadron colliders

19 Towards a precise determination of $\alpha_s$ from the Z boson $q_T$ spectrum

Speaker: Giulia Marinelli

20 Impact of higher-order theory uncertainties on alpha_s extractions at the LHC

Speaker: Rene Poncelet (IFJ PAN Krakow)

10:00 Coffee break

alpha_s from e+e- hadronic final states

21 alpha_s from event shapes

Speaker: Paolo Nason

22 Alphas from Precision e+e- Event Shapes

Speaker: Prof. Iain Stewart

23 \alpha_S determination from thrust distribution at N3LL+NNLO in QCD

Speaker: Giancarlo Ferrera (University of Milan)

12:00 Lunch / Ski

alpha_s from e+e- hadronic final states

24 Summary of the CERN workshop on alpha_s and thrust

Speakers: Gherardo Vita, Pier Francesco Monni (CERN)

25 Measurements of Hadronic Final States in Archived LEP Data

Speaker: Anthony Badea (University of Chicago (US))

26 Sudakov Shoulder Factorization For Event Shapes

Speaker: Arindam Bhattacharya

27 Improve alpha_s extraction from heavy jet mass data

Speaker: Xiaoyuan Zhang (MIT)

19:00 Dinner

Thursday 18 December

alpha_s from e+e- hadronic final states

28 Track energy-energy correlators as precision probes of the strong coupling

Speaker: Yibei Li

29 alpha_s from EEC confinement plateau

Speaker: Hao Chen (MIT)

10:00 Coffee break

alpha_s from e+e- hadronic final states

30 Towards an alpha_s extraction from track-based energy correlators at LEP

Speaker: Wouter Waalewijn (University of Amsterdam)

31 Discussion: alpha_S from e+e- hadronic final states

Speaker: Pier Francesco Monni (CERN)

12:00 Lunch / Ski

alpha_s from tau decays

32 Determination of the strong coupling from tau decays: current status

Speaker: Antonio Pich (IFIC, University of Valencia - CSIC)

33 $\alpha_s$ from $\tau$ decays including $\tau\to2\pi\nu_\tau$ from Belle

Speaker: Diogo Boito (University of Sao Paulo)

alpha_s from tau decays

34 Comparison between approaches to the determination of alpha_s from hadronic tau decays

Speaker: Santi Peris

35 Higher-order hadronic vacuum polarization contributions to the muon anomalous magnetic moment

Speaker: Dr Alexander Nesterenko (JINR)

19:00 Dinner

Friday 19 December

alpha_S from electroweak observables

10:00 Coffee / Tea break

36 alpha_s world average determination

Speakers: Giulia Zanderighi (Max Planck Society (DE)), Giulia Zanderighi (CERN), Joey Huston (Department of Physics and Astronomy), Joey Huston (Michigan State University (US)), Klaus Rabbertz (KIT - Karlsruhe Institute of Technology (DE))

37 alpha_s world average: Discussion

Speakers: Giulia Zanderighi (Max Planck Society (DE)), Giulia Zanderighi (CERN)