QCD@LHC 2026

28 Sept 2026, 09:00 → 2 Oct 2026, 13:00 Europe/London

University of Oxford

The 16th edition of QCD@LHC, aimed at fostering discussions and collaboration between experimenters and theorists working on strong interactions at the LHC, will be held at the University of Oxford, in the Department of Physics and St. Anne's College.

The workshop will will run from 9am on Monday 28 September to 1pm on Friday 2 October and consist of plenary and parallel sessions.

Scientific Programme

The parallel sessions will be on the following topics:

• Higgs, EW, BSM physics. Conveners: Alexander Karlberg (TH), Caterina Vernieri (ATLAS), Mika Vesterinen (LHCb) + Daniel Winterbottom (CMS)
• Heavy-quarks. Conveners: Chiara Savoini (TH), Riccardo Manzoni (CMS), Ivan Polyakov (LHCb) + Marcos Miralles Lopez (ATLAS)
• PDFs and DIS. Conveners: Thomas Cridge (TH), Gitanjali Poddar (ATLAS), Kenneth Long (CMS), Ciprian Gal (EIC)
• High-scale QCD. Conveners: Federico Buccioni (TH), Federico Sforza (ATLAS), Jennifer Roloff (CMS)
• Low-scale QCD, including heavy-ion physics. Conveners: Adam Takacs (TH), Alice Ohlson (ALICE), Ynyr Harris (ATLAS), Georgios Krintiras (CMS), Imanol Corredoira (LHCb)
• New techniques, tools and generators. Conveners: Emanuele Re (TH), Frank Siegert (ATLAS), Kyle Cormier (CMS)

Confirmed theory plenary speakers are Simon Badger, Stefano Forte, Marina Marinkovic, Guilherme Milhano, Tilman Plehn, Laura Reina, Steffen Schumann, Chiara Signorile-Signorile, Wouter Waalewijn, James Whitehead.

There will also be a panel discussion on the value of the strong coupling constant, with David d'Enterria, Alberto Ramos and Giulia Zanderighi as panellists.

Schedule

	Monday	Tuesday	Wednesday	Thursday	Friday
morning	plenary	plenary	plenary	parallel	plenary
afternoon	parallel	parallel	free	parallel
evening	reception			dinner

Registration and abstract submission

Registration and abstract submission are expected to open in April. Deadlines will be

• 1 July for abstract submission, now extended to 15 July
• 2 August for early registration (fee of £350), now extended to 16 August
• 4 September for final registration (fee of £380)

The registration fee will include the cost of lunches (Monday-Thursday), the reception and conference dinner. Thanks to support from the IPPP (Durham), we are able to offer a reduced fee for PhD students, of £300 for early registration (£330 late registration)

Accommodation

We have a block booking for accommodation at St. Anne's College for the 5 nights from Sunday 27 September to Friday 2 October. The price will be £450. 

International Advisory Committee

Sergey Alekhin (Hamburg), Johannes Blümlein (DESY), Stefan Dittmaier (Freiburg), Claude Duhr (Bonn), Keith Ellis (Durham), Thomas Gehrmann (Zürich), Nigel Glover (Durham), Joey Huston (Michigan State), Karl Jacobs (Freiburg), Judith Katzy (DESY), Frank Krauss (Durham), Jean-Philippe Lansberg (Orsay), Fabio Maltoni (Louvain), Michelangelo Mangano (CERN), Zoltan Nagy (DESY), Eram Syed Rizvi (QMUL), Frank Siegert (Dresden), Dominik Stöckinger (Dresden), Robert Szafron (BNL), Zoltan Trocsanyi (Budapest), Doreen Wackeroth (Buffalo), Ciaran Williams (Buffalo).

Local Organising Committee

Co-chairs: Fabrizio Caola (Oxford), Claire Gwenlan (Oxford), Chris Hays (Oxford), Gavin Salam (Oxford)

Members: Sneha Malde (Oxford), Martin Völkl (University of Birmingham), Nick Wardle (Imperial College London)

Monday 28 September

09:00 → 10:40 Plenary

09:00 Welcome

Speakers: Chris Hays (University of Oxford (GB)), Claire Gwenlan (University of Oxford (GB)), Fabrizio Arturo Caola (University of Oxford (GB)), Gavin Salam (University of Oxford)

09:10 Overview of CMS results

Speaker: Robert Schoefbeck (Austrian Academy of Sciences (AT))

09:40 Overview of ATLAS results

10:10 Recent developments in PDFs

Speaker: Stefano Forte (Università degli Studi e INFN Milano (IT))

10:40 → 11:10 Tea and coffee

11:10 → 12:40 Plenary

11:10 PDFs: an experimental perspective

Speaker: Amanda Sarkar (University of Oxford (GB))

11:40 Recent developments in shower matching

Speaker: James Whitehead (Jagiellonian University, Kraków)

12:10 Generators and Tools in the experiments

Speaker: Dr Francesco Giuli (INFN e Universita Roma Tor Vergata (IT))

12:40 → 14:00 Lunch

14:00 → 15:40 Higgs, EW, and BSM

Convener: Daniel Winterbottom (Imperial College (GB))

14:00 → 15:40 Low-scale QCD, including heavy-ion physics

14:00 → 15:40 PDFs and DIS

Convener: Gitanjali Poddar (University of London (GB))

14:00 Towards the NNPDF4.1 global PDF analysis

We present NNPDF4.1, a new release of the NNPDF family that consolidates and extends theoretical, methodological, and experimental progress achieved since NNPDF4.0. On the theory side, predictions for hadron collider observables are now based on state-of-the-art NNLO calculations interfaced to fast interpolation grids, and the analysis systematically incorporates missing higher order uncertainties (MHOUs), approximate N3LO corrections, and QED effects with the photon PDF. On the methodology side, NNPDF4.1 is based on an ensemble of ML models rather than a single one, following a new GPU-accelerated approach to hyperparameter optimisation, and benefit from improved positivity constraints, more general flavour assumptions, and an extended closure and future test validation. The input dataset is enlarged by more than 1200 new data points from 27 new datasets, including several Run II legacy measurements entering a PDF determination for the first time, selected through a systematic dataset selection procedure. We compare NNPDF4.1 to previous NNPDF determinations and to other recent PDF fits, and present a first study of its phenomenological implications.

Speaker: Kamil Laurent (Nikhef)

14:25 MSHT: Updates

We provide an update of the MSHT parton distribution functions. We concentrate on the impact of both new data sets and an improved theoretical and statistical analysis for PDFs at high x values, including an investigation. of higher twist contributions. We also consider the potential impact of Electron Ion Collider DIS data on PDFs, and in particular on the extraction of the strong coupling constant. Finally, we present an update of the MSHT20 approximate N3LO PDFs

Speaker: Dr Lucian Alexander Harland-Lang (University College London)

14:50 New Directions in Precision PDF Analysis

We present recent developments in the global analysis of the proton, including those within the CT25 family of precision parton distribution functions (PDFs) and related theoretical and methodological advances. Beyond the phenomenological implications of CT25 for collider predictions at the LHC and elsewhere, we also discuss novel approaches to nonperturbative parametrization and the growing role of AI/ML techniques in the hadron structure inferencing problem. Together, these efforts point toward a more flexible and expressive framework for extracting PDFs from an increasingly diverse body of high-energy data.

Speaker: Timothy Hobbs (Argonne National Laboratory)

15:15 Studies of N3LO corrections and resummation scale uncertainties in fits to DIS data using xFitter

We investigate the impact of recently computed N3LO corrections to QCD splitting and deep-inelastic scattering (DIS) coefficient functions on fits of parton distribution functions (PDFs) using the xFitter framework. By comparing fits performed at different perturbative orders, we analyze the resulting modifications to the PDFs and their associated uncertainties, incorporating correlated experimental errors. The results demonstrate the importance of N3LO corrections and highlight the need for further theoretical refinement in the low-x regime. Furthermore, we study the impact of resummation-scale variations on the splitting functions and on the strong coupling constant $\alpha_{s}$. These variations introduce a significant additional uncertainty in the PDFs that has not been considered previously. We study the impact of this uncertainty on fits of HERA DIS data and its implications for predictions of top quark pair production at the LHC.

Speaker: Dr Francesco Giuli (INFN e Universita Roma Tor Vergata (IT))

15:40 → 16:00 Tea and coffee

16:00 → 17:40 Heavy Quarks

16:00 → 17:40 High-scale QCD

16:00 → 17:40 New techniques, tools and generators

18:00 → 20:00 Reception

Tuesday 29 September

09:00 → 10:30 Plenary

09:00 QCD measurements at high scales

Speaker: Matt LeBlanc (Brown University (US))

09:30 Recent developments in QCD predictions for collider physics

Speaker: Chiara Signorile-Signorile (CERN)

10:00 EEC, Track functions and related topics

Speaker: Wouter Waalewijn (University of Amsterdam)

10:30 → 11:00 Tea and coffee

11:00 → 12:30 Plenary

11:00 Recent lattice developments and results

Speakers: Marina Krstic Marinkovic (ETH Zurich), Marina Krstic Marinkovic (ETH Zurich)

11:30 Panel discussion on alpha_s

Speakers: Alberto Ramos Martinez (Univ. of Valencia and CSIC (ES)), David d'Enterria (CERN), Giulia Zanderighi (Max Planck Institut für Physik)

12:30 → 14:00 Lunch

14:00 → 15:40 Heavy Quarks

14:00 → 15:40 Higgs, EW, and BSM

Convener: Daniel Winterbottom (Imperial College (GB))

14:00 → 15:40 PDFs and DIS

Convener: Gitanjali Poddar (University of London (GB))

14:00 Drell-Yan measurements with CMS for PDF determinations

Differential measurements of the Drell-Yan cross section play a central role in constraining the proton parton distribution functions (PDFs) while simultaneously enabling precision tests of perturbative QCD. Measurements spanning inclusive Drell-Yan production and final states in association with jets explore complementary regions of the parton momentum fractions and momentum-transfer scales.

In particular, Z+jet production allows the boost and scattering dynamics of the hard interaction to be disentangled. The average rapidity of the Z boson and the jet is sensitive to the longitudinal boost of the underlying partonic system, while their rapidity difference characterizes the scattering kinematics in the partonic center-of-mass frame. Combined with the transverse momentum of the Z boson, these observables offer increased sensitivity to the proton PDFs.

Comparisons with state-of-the-art NNLO QCD predictions, supplemented by NLO electroweak and nonperturbative corrections, demonstrate the sensitivity of these measurements to the proton PDFs and their potential impact on future global PDF determinations.

Speaker: Bhawna Gomber (University of Hyderabad, India)

14:20 Simultaneous PDF fits and parameter extractions (including weak mixing angle and alpha_s) at CMS

Simultaneous PDF fits and parameter extractions (including weak mixing angle and alpha_s) at CMS

Speaker: Bhawna Gomber (University of Hyderabad, India)

14:40 alphaS measurements from ATLAS

This talk will cover recent ATLAS determinations of the strong coupling constant, $\alpha_s$, highlighting the increasingly important role of parton distribution functions in precision measurements.

Speaker: Gitanjali Poddar (University of London (GB))

15:00 Electroweak measurements at LHCb and their interplay with proton PDFs

The forward acceptance of the LHCb detector provides unique sensitivity to parton distribution functions in kinematic regions complementary to those probed by other LHC experiments. This talk reviews electroweak measurements at LHCb and their role in constraining proton structure. Particular attention is given to the interplay between PDF uncertainties and precision electroweak observables: quantities such as the W boson mass and the effective leptonic weak mixing angle are increasingly limited by knowledge of the proton's partonic content, while LHCb production measurements offer constraining power on the same distributions. Recent results are presented alongside prospects for forthcoming measurements with Run 3 data, and the potential for dedicated forward measurements to reduce PDF uncertainties in future precision tests of the Standard Model is discussed.

Speaker: William Barter (University of Edinburgh)

15:20 Proton structure at the LHC with neural simulation-based inference

The precise determination of the parton distribution functions (PDFs) of the proton is an essential ingredient for LHC analyses, including the upcoming High-Luminosity upgrade. PDFs are determined from a global scattering of hard scattering data taking as input unfolded low-dimensional binned cross- sections. In this work we demonstrate the feasibility of deploying neural simulation-based inference (NSBI) to constrain the proton PDFs from unbinned, high-dimensional, detector level observables taking into account all relevant experimental and theoretical systematic uncertainties. We develop procedures that allows for a detailed account of systematic uncertainties in the unbinned modeling of the high-dimensional data set and how that interplays with the PDF extraction. Adopting as proof-of-concept the determination of the large-x gluon PDFs from top quark pair production, preliminary results with our pipeline demonstrate significant sensitivity improvements as compared for traditional low-dimensional binned analyses.

Speaker: Robert Schoefbeck (Austrian Academy of Sciences (AT))

15:40 → 16:00 Tea and coffee

16:00 → 17:40 High-scale QCD

16:00 → 17:40 Low-scale QCD, including heavy-ion physics

16:00 → 17:40 New techniques, tools and generators

Wednesday 30 September

09:00 → 10:30 Plenary

09:00 QCD measurements at low scales

Speaker: Weijie Jin (University of Zurich (CH))

09:30 Low-scale QCD in simulations

Speaker: Steffen Schumann

10:00 Recent spectroscopy measurements

Speaker: Jibo He (University of Chinese Academy of Sciences (CN))

10:30 → 11:00 Tea and coffee

11:00 → 13:00 Plenary

11:00 Results on CP Violation and B anomalies

Speaker: Christoph Michael Langenbruch (Heidelberg University (DE))

11:30 Heavy-flavour/Top precision predictions at colliders

Speaker: Simon David Badger (Universita e INFN Torino (IT))

12:00 Top measurements at the LHC

13:00 → 14:00 Lunch

Thursday 1 October

09:00 → 10:40 Higgs, EW, and BSM

Convener: Daniel Winterbottom (Imperial College (GB))

09:00 → 10:40 Joint: New techniques & High-scale QCD

09:00 → 11:00 PDFs and DIS

Convener: Gitanjali Poddar (University of London (GB))

09:00 Prospects for proton structure functions, PDFs, and strong coupling determinations at the EIC

Of the many measurements that will be possible at the Electron-Ion Collider (EIC), inclusive Deep Inelastic Scattering (DIS) measurements offer excellent opportunities to advance our understanding of the collinear structure of the proton, and QCD. We explore the potential for extracting proton structure functions, proton parton density functions (PDFs), and the strong coupling $\alpha_s(M_Z^2)$, using simulated EIC data, both standalone, and in combination with HERA data. Different beam energy and luminosity scenarios are considered, and the Rosenbluth separation method is used to determine the precision with which the proton structure functions $F_2$ and $F_L$ may be extracted at the EIC, in a model-independent manner. Additionally, the impact of EIC electron-proton DIS data on the precision of the proton PDFs is evaluated through the inclusion of simulated data in a global QCD fit at NNLO, performed in the HERAPDF2.0 framework. The simultaneous fitting of the PDFs and $\alpha_s(M_Z^2)$ indicates that the strong coupling may be determined to potentially world leading precision with inclusive DIS data alone, even during the early years of EIC operation.

Speaker: Stephen Maple

09:20 MORPH: Multimodal Observables and Representations for the Physics of Hadrons

Determining high-fidelity, flexible parameterizations of hadronic parton distribution functions from experimental data remains a long-standing goal in precision phenomenology. Traditionally, this problem is addressed through dedicated, large-scale global analyses spanning hundreds of experimental datasets and conditioned on underlying theory choices such as perturbative order, potential beyond Standard Model contributions, and many other fitting assumptions. This has produced an ecosystem of PDF determinations that are connected through the underlying QCD theory, but difficult to interpolate between directly. It is within this ecosystem that we present MORPH, a foundation-model framework for learning reusable, uncertainty-aware representations of hadron structure, designed to provide a universal backbone for PDF inference across theory choices and observable modalities. MORPH currently uses self-supervised representation learning to encode ensembles of fitted PDF replicas into a structured latent space that captures the full flavor and x-dependence with calibrated uncertainty reconstruction. We benchmark this representation using a suite of machine-learning and physics-based scaling studies to determine whether it preserves the QCD information carried by the original ensembles. A central aim of MORPH is to condition this latent space on theory metadata inputs, enabling interpolation across PDF phenomenological extractions as a fast-evaluation complement to dedicated global fits. I will present progress in building this foundation-model for PDF ensembles, discuss the physics diagnostics needed to validate such representations, and outline a path toward fast, generative inverse mapping of the non-perturbative structure of the proton relevant for the next generation of particle physics experiments.

Speaker: Brandon Kriesten (Argonne National Laboratory)

09:40 Interpreting Parton Distributions with Shapley Values

We present a new method to interpret PDFs using the game theoretical method of Shapley values. We use it to assess the impact of data on PDFs when determining them, and the impact of individual PDFs on collider observables. In general we recover the expected pattern of PDF sensitivity to data for modern global PDF sets. We also uncover pronounced localised losses of sensitivity that are not reflected in the uncertainty bands of the PDFs, which is potentially relevant for BSM searches. In particular we find a loss of sensitivity of the gluon PDF in the region of momentum fraction of Higgs production.

Speaker: Eva Groenendijk (University of Milan)

10:00 Analaysis of the impact on data uncertanties with the MSHT framework

We investigate the impact of modifications to the standard approach to data uncertainties in PDF fits in the context of the MSHT framework. We consider the potential for ``errors on errors'' and the consequence of this in data distributions and in fitting procedures. We also consider the degree of correlation in the treatment of correlated systematic uncertainties, and introduce a novel technique for relaxing the correlations on uncertainties determined by modelling in a physically motivated manner. We look at the impact on LHC data, with a particular emphasis on recent jet and dijet data from ATLAS and CMS.

Speaker: Robert Samuel Thorne (University College London (UK))

10:20 Designing Precision-Oriented PDF Sets for Electroweak Measurements at Hadron Colliders

Uncertainties associated with parton distribution functions (PDFs) remain among the dominant systematic uncertainties in precision measurements of the W boson mass. A robust assessment of PDF-related uncertainties is therefore essential for future combinations of $m_W$ measurements. Drell-Yan (DY) observables, including the Z boson rapidity $y_Z$ distribution, the W boson charge asymmetry $A_W$, and the charged lepton asymmetry $A_{\ell}$, provide constraints on the parton distributions that govern the W boson rapidity $y_W$ and the lepton kinematics used in the determination of $m_W$.

In this work, the performance of several modern PDF sets for precision electroweak (EW) measurements is evaluated through a compatibility study with the aforementioned DY datasets from the ATLAS, CMS, LHCb, CDF and D0 experiments. Theory predictions are computed at NNLO in QCD with NNLL resummation using DYTurbo, and compared with the measurements through a $\chi^2$ statistic that incorporates experimental correlations and PDF uncertainties. This study will identify the PDF sets that provide the best overall description of the DY data and are therefore the most suitable candidates for future global combinations of $m_W$ measurements. In addition, PDF profiling will be performed to quantify the constraints imposed by the individual DY measurements on the parton distributions relevant for precision EW observables.

In this talk, results from the compatibility and profiling studies will be shown, demonstrating how these studies can inform the development of PDF sets tailored to high-precision EW measurements at hadron colliders.

Speaker: Baris Tuncay (University of Oxford (GB))

10:40 → 11:10 Tea and coffee

11:10 → 12:50 Heavy Quarks

11:10 → 12:50 High-scale QCD

11:10 → 12:50 Joint: New techniques & Higgs, EW, and BSM

Convener: Daniel Winterbottom (Imperial College (GB))

12:50 → 14:00 Lunch

14:00 → 15:40 Higgs, EW, and BSM

Convener: Daniel Winterbottom (Imperial College (GB))

14:00 → 15:40 Joint: Heavy Quarks & Low-scale QCD

14:00 → 15:40 Joint: New techniques & Amplitudes

15:40 → 16:00 Tea and coffee

16:00 → 17:40 Joint: Heavy Quarks & Low-scale QCD

16:00 → 17:40 Joint: New techniques & Amplitudes

16:00 → 17:40 PDFs and DIS

Convener: Gitanjali Poddar (University of London (GB))

16:00 On the N3LO evolution of the PDFs from moments

The N3LO evolution of the PDFs is one of the required ingredients for percent-level precision phenomenology at the HL-LHC.
This talks reviews the progress in parameterising the evolution kernels by computing analytically a set of the moments of these quantities and imposing physical constraints.

Speaker: Giulio Falcioni

16:20 The 3-loop variable flavor number scheme

We describe the variable flavor number scheme to three-loop order, which modifies
the massless parton densities by single- and two-mass effects and introduces heavy-quark
parton distribution functions for charm and bottom. A renormalization group analysis
shows the validity of this picture at large scales $Q^2$, where it resembles the
non-power-suppressed heavy-flavor corrections completely. We also provide numerical
implementations of a series of charged and neutral current Wilson coefficients

Speaker: Prof. Johannes Bluemlein (DESY)

16:40 On recent extractions of TMD distributions

In this talk, I will discuss the current status of TMD extractions.I will highlight recent progress, including neural-network parameterisations, applications to precision measurements of the strong coupling and the W boson mass, and the extraction of gluon TMDs from LHC data.

Speaker: Dr Valerio Bertone (C.E.A. Paris-Saclay)

17:00 Status of Nuclear PDF Determinations

Nuclear parton distribution functions (nPDFs) are a key ingredient for precision studies of high-energy nuclear collisions. This talk will review the current status of global nPDF analyses, focusing on recent determinations including EPPS21, nNNPDF3.0, and nCTEQ26. We will discuss the impact of new experimental constraints, similarities and differences between the various fitting frameworks, and the resulting uncertainties on parton distributions in nuclei. Special attention will be paid to the strange-quark and gluon distributions, as well as to the nuclear (A) dependence.

Speaker: Prof. Michael Klasen (University of Münster)

17:20 Constraining proton structure and deuteron effects at large x: the CJ26 global analysis

We present CJ26, the latest CTEQ-JLab global QCD analysis, which simultaneously determines the proton parton distribution functions and nuclear corrections in deuteron targets. The analysis includes, for the first time in a global fit, the full JLab 6 GeV inclusive DIS dataset together with the first published measurements from the 12 GeV era. Focusing on the large-xx region, we examine the interplay between higher-twist contributions and nucleon off-shell effects in low-energy proton and deuteron data, and assess their impact on the extracted quark and gluon distributions. We also demonstrate the importance of a careful treatment of correlated experimental systematic uncertainties for obtaining high-precision PDF determinations, and discuss how future measurements will further improve our understanding of nuclear effects and the partonic structure of light nuclei.

Speaker: Matteo Cerutti (CEA Paris-Saclay)

18:30 → 21:00 Conference dinner

Friday 2 October

09:00 → 10:30 Plenary

09:00 Higgs, Electoweak, and Beyond at the LHC

Speaker: Chris Pollard (University of Warwick (GB))

09:30 Recent developments in Electroweak/Higgs/SMEFT predictions

Speaker: Laura Reina

10:00 AI and collider physics

Speakers: Tilman Plehn, Tilman Plehn (Heidelberg University)

10:30 → 11:00 Tea and coffee

11:00 → 13:00 Plenary

11:00 Recent developments in heavy-ion physics

Speakers: Dr Guilherme Milhano (LIP-Lisbon & CERN TH), Guilherme Teixeira De Almeida Milhano

11:30 Heavy ions and fixed-target measurements at LHCb

Speaker: Michael Winn (Université Paris-Saclay (FR))

12:00 Plenary (ALICE)

12:30 Status of the EIC

Speakers: Abhay Deshpande, Abhay Deshpande (Stony Brook University)