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 Soft QCD measurements with pp collisions in ATLAS

Measurement of soft QCD and DPI-related processes offer insights to understand QCD phenomena at small energy scales and non-perturbative regime, probe mechanisms for multi-parton interactions, and search for undiscovered phenomena such as QCD instantons. This talk presents the relevant results in this sector from the ATLAS experiments

Speaker: ATLAS Collaboration

14:20 Minibias measurements with pO collisions in ATLAS

The utilisation of pO collision events at the LHC offers complementary means to test QCD predictions, and in particular provides sensitive probes to hadronic models that connect with cosmic-ray physics. This talk presents the minibias measurements with pO collusions from the ATLAS experiment.

Speaker: ATLAS Collaboration

14:40 Jet production in photon-lead collisions at NLO+PS accuracy

Ultraperipheral Pb+Pb collisions at the LHC produce quasi-real photons reaching high energies, making photonuclear jet production a probe of the partonic structure of both the nucleus and the photon. We present NLO+PS predictions for photonuclear jet production matched to the observables of the ATLAS UPC Pb+Pb measurement at sqrt(s_NN) = 5.02 TeV. This provides the parton-shower-matched calculation identified as necessary for incorporating this data into global PDF fits. We quantify and compare scale, photon-PDF, and nuclear-PDF uncertainties across the measured phase space. These results are directly relevant to upcoming global fits of both nuclear and photon PDFs, with implications extending to the Electron-Ion Collider programme.

Speaker: Peter Meinzinger (Zürich University)

15:00 Using low-pt dimuon events to measure transverse proton structure

We present new methods for measuring the transverse structure of the proton, relying on ratios of event activity variables between events with a low-pt pair of muons and minimum bias events. The event activity is used in a similar way to centrality in heavy ion physics, and the evolution of the hard-process cross section provides information on the effective partonic luminosity as a function of the impact parameter between the protons. We show how the measured effective luminosity can be used to calculate the expected Double Parton Scattering (DPS) cross section within the pocket formula framework. The dependence of the transverse proton structure and the DPS cross section on partonic-x can be measured with this method. Observation of this dependence is expected to be achievable with currently collected data by the LHC experiments based on estimates of the effect size in pythia models.

Speaker: Kyle Cormier (University of Zurich (CH))

15:20 Beam-spin induced polarization of lambda and anti-lambda hyperons in semi-inclusive deep-inelastic scattering

The beam-spin induced polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons produced in deep-inelastic scattering of longitudinally polarized positrons from unpolarized nucleons has been investigated by the HERMES experiment at a positron beam energy of 27.6 GeV impinging on hydrogen, deuterium, and various heavier gas targets. The two spin-transfer coefficients $D_{LX}$ and $D_{LZ}$ are extracted and are found to be small and mostly compatible with zero within their statistical and systematic uncertainties, essentially independent of the relevant kinematic variables. The results constrain novel spin-dependent fragmentation functions, among others the helicity fragmentation function describing the hadronization of longitudinally polarized quarks into longitudinally polarized hadrons.

Speaker: HERMES Collaboration

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 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

15:40 → 16:00 Tea and coffee

16:00 → 17:40 Heavy Quarks

16:00 Hadronization studies at LHCb

The forward coverage of the LHCb detector (2 < η < 5) provides an interesting setting to
study hadronization in jets. LHCb is particularly well-suited for studying hadronization in
events initiated by light-quarks and heavy-quarks, given the enhancement of the relevant
cross sections at forward rapidities and the capability of cleanly tagging these events.
Heavy-flavour-tagged events are of special interest, as heavy quarks exhibit distinct
perturbative radiation patterns and nonperturbative hadronization dynamics compared to
light quarks and gluons. In this talk, we will briefly review the experimental conditions at
LHCb to provide context for the measurements, and then delve deeply into the latest results
of hadronization studies at LHCb

16:20 Heavy-flavour jet measurements with ALICE

Measurements of heavy-flavour jets in pp collisions provide important tests of Quantum Chromodynamics (QCD) calculations. Jet substructure observables offer insight into the parton-shower evolution and the different radiation patterns of quarks and gluons arising from the different Casimir colour factors and parton masses. Comparisons between jets containing heavy-flavour baryons or heavy-flavour mesons probe heavy-quark hadronisation mechanisms and test the assumption of universality of charm-quark hadronisation across different collision systems.

In this contribution, a collection of recent ALICE measurements about heavy-flavour jets in pp collisions is presented. First, a set of observables involving charm jets identified by reconstructing $\mathrm{D^{0}}$ mesons is shown. We discuss measurements related to different choices of jet-axis definition, complemented by the generalised jet-angularity measurements for $\mathrm{D^{0}}$-tagged jets. These two measurements provide systematic insight into the radiation pattern and fragmentation of charm quarks during the parton-shower evolution. Then, we present the first measurement of the energy-energy correlator in $\mathrm{D^{0}}$-tagged jets, which resolves the angular structure of the energy flow of QCD radiation and allows for the separation of perturbative and non-perturbative regimes. Extending these studies in the charm-baryon sector, we compare the results of $\mathrm{D}$-meson jets with those of $\mathrm{\Lambda^{+}_{c}}$-tagged jets, thereby providing insight into charm-quark hadronisation mechanisms. Finally, we present the new b-jet production cross section measured with a b-jet tagging algorithm based on a graph neural network. These results provide new benchmarks for perturbative QCD calculations and establish a baseline for future b-quark energy loss studies in heavy-ion collisions.

Speaker: Yoshini Bailung (Institut de Physique des 2 Infinis (IP2I) de Lyon, CNRS-IN2P3, Université de Lyon)

16:40 Substructure of Heavy Quark Jets

We will present new results for the jet substructure of heavy quark initiated jets, focussing on jet angularities measured on jets initiated by a b-quark and discuss phenomenological results from arXiv:2606.20798.

Speaker: Andrea Ghira (Università degli studi di Genova)

17:00 Flavor Anomalies and Lepton Flavor Universality at CMS

Over the past decade, several measurements in the flavor sector performed at dedicated beauty experiments, such as BELLE, BaBar and LHCb, have shown a significant tension with respect to SM predictions. The flavor puzzle of the SM remains one of the open questions in high energy particle physics up until today and needs further investigation. This talk summarizes flavor measurements performed at the CMS detector over the last years, underlining its B physics potential and contribution to the flavor sector.

Speaker: Bhawna Gomber (University of Hyderabad, India)

17:20 Analytic Computation of the Two-Loop Penguin Jet Function

In this talk, I will present recent progress in the analytic computation of the two-loop penguin jet function. This function is a key ingredient in the factorised description of the $Q_1$-$Q_{7\gamma}$ interference contribution to inclusive (B)-meson decays, which constitutes an important source of theoretical uncertainty in precision flavour physics. Its analytic computation therefore represents an important step towards improving theoretical predictions for these observables.
This calculation requires the evaluation of a set of master integrals that depend on the charm-quark mass as well as the energy sharing between the quark and antiquark. I will demonstrate how all relevant master integrals can be computed analytically in terms of iterated integrals by separating the dependence on the different scales.

Speaker: Kevin Brune (JGU Mainz)

16:00 → 17:40 High-scale QCD

Conveners: Federico Buccioni (CERN), Dr Federico Sforza (University and INFN Genoa), Jennifer Roloff (Brown University (US))

16:00 QCD jet measurements in ATLAS

Direct measurements of processes involving QCD jets provide a key probe of QCD interactions, and in which, the multi-jet and vector boson plus jets processes are key channels in this measurement program. This talk presents recent measurements in this sector from the ATLAS experiment.

Speaker: ATLAS Collaboration

16:20 Accurate predictions for LHC Processes at the highest partonic energies

The predictions relevant for two recent measurements by ATLAS have highlighted the necessity of developing methods to systematically tackle the intricate behaviour of large logarithmic corrections in the perturbative series in order for predictions to be accurate and useful. Specifically, the analysis of the processes of the production of at least two jets ($pp\to jj$ [https://arxiv.org/abs/2405.20206]) and the production of a hard photon or an electroweak vector boson in association with at least two jets ($pp\to\{\gamma,Z,W}+jj$ [https://arxiv.org/abs/2403.02793]) all indicate systematic deviations from data with increasing partonic collision energy for e.g. fixed order perturbative predictions. Perturbative predictions taking into account the source of the large logarithmic corrections at high energies on the other hand obtain stable predictions of data [https://arxiv.org/abs/2403.02793, https://arxiv.org/abs/2506.17438].

While the high energy logarithmic corrections to the perturbative series have been studied for some time, this is the first conclusive demonstration of the need for their inclusion in standard analyses at the LHC. The predictions for photon+dijets taking into account the effects of high energy resummation was presented in https://arxiv.org/abs/2506.17438. In this talk we will present new results for the process Z+dijets, which confirm the dominance of the logarithmic terms in the NLO fixed-order results, and confirm the resolution of the logarithmic problem by an all-order resummation, which also compares favouably to experimental data. Finally, we discuss the merits of scale choices in fixed-order calculations of order the partonic collision energy.

Speaker: JEPPE ROSENKRANTZ ANDERSEN (IPPP, University of Durham)

16:40 Drell-Yan precision measurements in ATLAS

The precision measurements of Drell-Yan processes offer in-depth understanding of QCD interactions and important constraints on SM parameters and PDFs. This talk presents recent Drell-Yan precision results from the ATLAS experiment.

Speaker: ATLAS Collaboration

17:00 Diphoton production at N3LO

The production of two isolated photons in high-energy hadron collisions poses a challenge to perturbative QCD because of large corrections through next-to-next-to-leading order (NNLO). We present novel next-to-next-to-next-to-leading order (N3LO) predictions and finally demonstrate perturbative convergence for this process. We discuss the considerable computational challenges and phenomenological results for the Large Hadron Collider.

Speaker: Rene Poncelet (IFJ PAN Krakow)

17:20 Photon-induced QCD@FCC-ee

Lepton colliders produce large fluxes of quasi-real photons via the equivalent photon approximation. We present a study for the proposed FCC-ee, showing these fluxes enable a broad photon-QCD program.
While photon-induced dijet production gives access, for example, to $\alpha_S$ determinations, jet substructure, etc., the talk centers on deep-inelastic scattering of leptons on collinear photons. We determine the $(x,Q^2)$ coverage attainable at FCC-ee, after subtraction of the $ee \to WW$ background, and the role of forward lepton detectors.

Speaker: Peter Meinzinger (Zürich University)

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 ATLAS results on top properties and threshold region

In this contribution, the top quark mass measurements by the ATLAS experiment are reviewed. In addition, new ATLAS results on top-quark properties are shown. Finally, results of the measurements around the top pair production threshold are summarised.

Speaker: ATLAS Collaboration

14:20 Top quark pair in the threshold at the LHC: NRQCD and key-uncertainties

We present predictions for top quark pair production at the LHC in the threshold region, including quasi-bound-state effects associated with Coulomb interactions within the framework of NRQCD. We focus on the invariant mass distribution of the produced top quark pair, incorporating NLL soft-gluon threshold resummation.
A detailed study of the theoretical uncertainties affecting these predictions is presented. We consider variations in the top quark mass and width, the strong coupling $\alpha_s$, renormalization and factorization scales, and parton distribution functions, as well as uncertainties associated with the color-singlet and color-octet Green’s functions describing quasi-bound state formation. These uncertainties are compared with those from standard fixed-order QCD predictions, and implications for analyses by ATLAS and CMS are discussed.

Speaker: Giovanni Limatola (II. Institute for Theoretical Physics University of Hamburg)

14:40 ATLAS results on top quark cross section measurements and recent progress on modelling

The exceptionally large dataset collected by the ATLAS detector at the highest proton-proton collision energies provided by the LHC enables precision testing of theoretical predictions using an extensive sample of top quark events. Measurements of the inclusive top quark production rates at the LHC have reached a precision of several percent and test advanced Next-to-Next-to-Leading Order predictions in QCD. Differential measurements in several observables are important to test SM predictions and improve Monte Carlo generator predictions. In this contribution. several cross-section measurements will be presented as well as the studies on the state-of-the art Monte Carlo generators.

Speaker: ATLAS Collaboration

15:00 Complete NLO corrections to off-shell $t \bar{t}$ production in the $\ell+j$ decay channel

We present the calculation of the complete NLO corrections to the off-shell top-quark pair production in the $\ell+j$ decay channel, denoted as $pp \to \ell^- \bar{\nu}_{\ell}\, j_b j_b \,jj + X$, where $\ell^- = e^-,\, \mu^-$. The calculation consistently preserves the finite-width effects of the top quarks and massive gauge bosons, as well as takes into account all doubly-, singly-, and non-resonant contributions along with their interference effects. All Born-level contributions, at the perturbative orders from ${\cal O}(\alpha_s^4\alpha^2)$ to ${\cal O}(\alpha_s^0\alpha^6)$, are included and corrected by both NLO QCD and NLO EW effects. Furthermore, all possible partonic initial states are taken into account. Particular attention is paid to the infrared safety in the presence of photons and jets. This requires the use of the so-called parton-to-photon fragmentation function and the photon-to-jet conversion function, which makes the democratic photon–parton clustering and the $\gamma \to q\bar{q}$ splittings finite. We present our findings at the integrated and differential fiducial cross-section levels for the LHC Run III centre-of-mass energy of $\sqrt{s}= 13.6$ TeV. In addition, we quantify the impact of subleading NLO effects, in particular, electroweak Sudakov logarithms and non-resonant QCD backgrounds. Two analysis strategies are employed and compared, namely with and without the resonance-enhancing requirement on the invariant mass of the two light jets, $|M_{jj}-m_W|<{\cal Q}_{\text{cut}} = 20$ GeV, illustrating the relationship between QCD background suppression, off-shell effects, interferences, and complete NLO corrections.

Speaker: Leon Mans (RWTH Aachen University)

15:20 Top Quark Pair Production and Decay: The 1-Higgs-Singlet Model and Pseudoscalar Decay

The process of top quark pair production through the decay of the scalars in the 1 Higgs Singlet extension of the Standard Model is associated with large interference effects between the loop-induced 'SM-like' Higgs and the heavy Higgs amplitudes, and the QCD continuum background. We attach leptonic decays to the di-top final state at NLO and study the effects of spin correlation in the process. We also make phenomenological predictions for the leptonic decays of the top quark pair produced by the decaying of a CP-odd pseudoscalar at the LHC at NLO accuracy, with the full spin correlation effects preserved in the decayed products. We attach Parton Showers and perform analyses of differential cross sections as functions of various parameters to study the significance of the results in searches for new scalars and pseudoscalars beyond the Standard Model.

Speaker: Vishakha Lingadahally

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 ATLAS measurements of alphaS

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

Conveners: Federico Buccioni (CERN), Dr Federico Sforza (University and INFN Genoa), Jennifer Roloff (Brown University (US))

16:00 Measurement of resolved four-point energy-energy correlators at the CMS experiment

The immense flux of high-momentum jets produced by the LHC provides a unique opportunity to study the detailed dynamics of high-energy QCD. So-called “energy-energy correlator” observables provide a particularly compelling opportunity to uncover these dynamics by probing the internal structure of jets while maintaining a close connection to fundamental ingredients of QCD theory. The bulk scaling properties of 2- and 3-point energy-energy correlators have already been measured by several experiments, but the resolved structure of these observables is still completely unknown. We will discuss new experimentally-viable projections of the four-point energy-energy correlator, and then proceed to recent measurement of these observables by the CMS experiment in Z+jets events at a center-of-mass energy of 13 TeV. We will further discuss the practical challenges in measuring and unfolding these high-dimensional, highly-correlated data. These results provide a stringent test of parton shower dynamics and QCD factorizations, and provide a basis for new insights into the high-energy dynamics of QCD.

Speaker: Bhawna Gomber (University of Hyderabad, India)

16:20 New Opportunities for Precision Hadronic Measurements at the LHC with Energy Correlators

With exciting future collider programs, such as the FCCee, on the horizon, interpretation of precision measurements at these facilities requires us to have already constrained the Standard Model parameters to a high degree of precision. Collider measurements impacted by strong interactions such as the strong coupling constant and the top quark mass remain bottlenecks in this program. In this talk, we report on recent progress in overcoming these challenges using energy energy correlators (EECs).

In EECs measured on heavy unstable resonances such as the $Z$, $W$, $H$ and the top, the resonance mass $M$ introduces an additional scale, generating a sharp peak at angles $\sim M/p_T^{\rm jet}$. For heavy bosons exhibiting a two-body decay, such as the $Z$, this feature can be computed directly by boosting the EEC spectrum measured in $e^+e^- \rightarrow {\rm hadrons}$ at the $Z$ pole, where the peak arises from boosting the well-studied Sudakov factorization governing the back-to-back limit of the two-point correlator. Beyond just a theoretical excericse, this can be pushed even further to devise a new competitive collider measurement of the bottom quark mass by exploiting the dead-cone feature of inclusive bottom decays in boosted $Z$ jets, while at the same time laying the theoretical foundation for the top mass determination using EECs.

Speaker: Zhen Xu (DESY)

16:40 Accounting for the Effect of Fiducial Cuts on Energy-Energy Correlators

We study the impact of fiducial acceptance cuts on Energy-Energy Correlators (EECs) in $e^+e^-$ annihilation into hadrons. Experimental measurements of EECs typically impose an angular acceptance defined with respect to oriented event-shape axes, such as thrust or sphericity, and correct the resulting phase-space loss using Monte Carlo efficiency factors.
We instead adopt a fully analytic approach and compute the fiducial EEC to $O(\alpha_s)$ using thrust and sphericity axes. We find that the impact of finite angular acceptance on measured EECs can reach up to 3$\%$ for both axes and induce nontrivial shape distortions that are uncontrolled in MC. We further use symmetry arguments to decompose the all-order EEC in terms of scalar structure functions, and propose a data-driven defiducialization strategy (inspired by similar techniques at the Tevatron and the LHC) to rigorously reconstruct the full phase-space EEC directly from differential measurements, eliminating the need for MC efficiency corrections.

Speaker: Alessio Vorona (Nikhef/UvA)

17:00 Recent Highlights from the Electron–Positron Alliance

Recent advances in data preservation and modern analysis techniques have enabled a new generation of precision measurements using archived electron-positron collision data collected at the Large Electron-Positron Collider (LEP). The Electron-Positron Alliance is developing a broad physics program that applies contemporary experimental and theoretical tools to these unique datasets, establishing them as a precision laboratory for studies of Quantum Chromodynamics and jet physics. In this talk, we present an overview of recent results based on archived ALEPH and DELPHI data, including measurements of event-shape observables, jet spectra and substructure, energy-energy correlators, identified-particle production, and other precision QCD observables. These measurements probe perturbative radiation, hadronization, and the transition from partons to hadrons in a clean experimental environment, while providing stringent tests of modern event generators and theoretical calculations. We also discuss ongoing efforts to preserve, modernize, and extend the scientific reach of legacy collider datasets using new analysis methodologies. Together, these results demonstrate the continuing scientific value of archived LEP data, providing precision benchmarks for present and future collider experiments and illustrating the broader potential of the “recycling frontier” in particle physics.

Speaker: Ms Yi Chen (Vanderbilt University (US))

17:20 Event isotropy in perturbative QCD

It has recently been proposed that collider events can be equipped with a metric, the Energy Mover's Distance (EMD), which allows one to rephrase multiple aspects of collider physics in a geometric language. Further, the EMD can be exploited to define new observables. In this context, event isotropy quantifies the resemblance of an event to a uniform energy distribution. We present the first theoretical study of event isotropy within the framework of perturbative QCD. In particular, we first obtain the isotropy distribution in e+e− collisions semi-analytically at O(αs) (leading-order) and numerically at O(αs^2) (next-to-leading order, NLO). Furthermore, we obtain all-order theoretical predictions by resumming the contributions of soft and collinear emissions, at next-to-leading logarithmic (NLL) accuracy. By matching resummed and fixed-order predictions we reach NLL+NLO accuracy.

Speaker: Matteo Cacciari (LPTHE Paris)

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

16:00 Measurement of the jet quenching effect with Z+jet events in PbPb and pp collisions at 5.36 TeV with Run 3 data

The production of jets in association with Z bosons offers a uniquely clean probe of the quark-gluon plasma (QGP), as the Z boson's decay products bypass strong medium interactions, preserving the initial hard-scattering kinematics. We present the latest measurement of Z+jet correlations in the dimuon channel using the new 5.36 TeV Run 3 data collected by the CMS experiment in 2023 and 2024. The study focuses on the momentum imbalance between the Z boson and the recoiling jet, providing a direct and sensitive look at medium-induced energy loss and the in-medium evolution of partons. The unfolded $x_{Zj}$ distribution, compared with state-of-the-art theoretical calculations, offers crucial tests of the microscopic structure of the QGP. By leveraging the high statistics and increased energy of Run 3, this measurement provides new experimental leverage to constrain theoretical models of parton energy loss and the transport properties of the QGP. Furthermore, the unprecedented statistical precision of the anticipated full Run 3 dataset will pave the way for detailed studies of jet substructure in this clean Z+jet channel.

Speaker: Bhawna Gomber (University of Hyderabad, India)

16:20 How to actually measure jet quenching in heavy-ion collisions

The scattering of a well-controlled probe particle is a time-honored method to explore the structure and dynamics of matter. In heavy-ion collisions, the interaction of jets with the Quark-Gluon Plasma (“jet quenching”) promises such a probe. However, well-controlled jet reconstruction in the complex environment of nuclear collisions is extraordinarily difficult – the thousands of particles generated in a head-on collision of lead ions at the LHC do not come labeled “jet” or “background.” The HEP jet toolkit for mitigating underlying event and pileup effects in p+p collisions is helpful for very energetic jets in this environment, where the signal/background is large. However, such jet-wise correction approaches fail badly for by far the largest part of jet production phase space, where jet quenching effects are expected to be sizable, and where we need to measure to track the dissolution of jets in the plasma. Machine Learning is useless in this region, because its training requires accurate background modeling (which is what the problem is). The solution, unsurprisingly, is to think about the problem statistically, carrying out data-driven background corrections at the level of ensemble-averaged distributions. This approach has been successfully applied in a wide variety of heavy-ion jet measurements at both the LHC and RHIC, enabling jet quenching measurements over the full jet production phase space at both colliders, and mapping experimentally how moderate-energy jets get blown apart by the QGP and how the QGP responds to that excitation. I will outline the statistical approach to heavy-ion jet measurements, and discuss notable recent results employing it from both the ALICE and STAR experiments.

Speaker: Peter Martin Jacobs (Lawrence Berkeley National Lab. (US))

16:40 Measurement of hyperon spin correlation in pp and pPb collisions at CMS

Spin correlations between hyperons provide a novel probe of spin-dependent particle production and hadronization in quantum chromodynamics (QCD). Using the high-statistics data collected by the CMS experiment, we present the first measurements of spin correlations for $\Lambda\Lambda$, $\Lambda\bar{\Lambda}$, and $\bar{\Lambda}\bar{\Lambda}$ pairs in pp collisions at $\sqrt{s}=13$ TeV and pPb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV. The correlations are measured as a function of the pair separation, $\Delta R=\sqrt{\Delta\eta^{2}+\Delta\phi^{2}}$. At small $\Delta R$, $\Lambda\Lambda$ and $\bar{\Lambda}\bar{\Lambda}$ pairs exhibit negative short-range spin correlations. No significant positive short-range spin correlation is observed for $\Lambda\bar{\Lambda}$ pairs, in qualitative contrast to previous observations at lower collision energies. These measurements provide new constraints on models of hyperon-pair production and on the origin of spin correlations in hadronic collisions.

Speaker: Jieke Wang (Shandong University (CN))

17:00 Collective flow measurements in OO and NeNe collisions with CMS

Measurements of collective flow in intermediate-size collision systems such as OO and NeNe are crucial for understanding the origin of collectivity in small systems and its evolution with collision system size. Using data collected by the CMS experiment at the LHC, flow coefficients of charged particles ($n=2,3$) are measured in OO and NeNe collisions using two- and multi-particle correlation techniques as functions of centrality. In addition, collective flow measurements of strange hadrons are presented to investigate the particle-species dependence. The results are compared with pp, pPb, and PbPb collisions, as well as with theoretical calculations, providing new insights into the origin of collectivity in small systems and information on the nuclear structure of oxygen and neon nuclei.

Speaker: Jiateng Peng (Fudan University)

17:20 System-size dependence of charged-particle production at mid and forward pseudorapidity with ALICE

The pseudorapidity dependence of charged-particle production provides information on the interplay between hard and soft QCD processes and is sensitive to non-linear QCD evolution in the initial state. For the LHC Run 3, ALICE has upgraded its detectors, increasing its pseudorapidity coverage and improving tracking of charged particles. This is done by combining the information from the upgraded Inner Tracking System (ITS) at mid-rapidity and the newly installed Muon Forward Tracker (MFT) at forward rapidity. In July 2025, the LHC delivered short light-ion runs with pO, OO, and Ne$-$Ne collisions, providing a unique opportunity to bridge the gap between proton$-$proton and heavy-ion collisions. This contribution presents new results from Run 3 on charged-particle multiplicity, allowing us to investigate the evolution of particle production with energy and system size with high precision. The measurement will be compared with models based on various particle-production mechanisms and different initial conditions at mid and forward rapidities.

Speaker: Gyula Bencedi (HUN-REN Wigner Research Centre for Physics (HU))

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 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))

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 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))

10:40 → 11:10 Tea and coffee

11:10 → 12:50 Heavy Quarks

11:10 ATLAS results on associated top quark production (Top+X) and EFT interpretations

The high center-of-mass energy of proton-proton collisions and the large available datasets at the CERN Large Hadron Collider allow the study of rare processes of the Standard Model with unprecedented precision. Measurements of rare SM processes provide new tests of the SM predictions with the potential to unveil discrepancies with the SM predictions or provide important input for the improvement of theoretical calculations. In this contribution, total and differential measurements of associated top-quark production are shown using data taken with the ATLAS Experiment at a center-of-mass-energy of 13 TeV. These measurements provide important bounds on the electroweak couplings of the top quark, often with Effective Field Theory interpretations and constrain backgrounds that are important in searches for Higgs production and for new phenomena beyond the SM

Speaker: ATLAS Collaboration

11:30 NNLO QCD corrections to $t\bar{t}W$ production at the LHC

In this talk I will present the numerical calculation of two-loop QCD amplitude
for the associated production of a top-anti-top pair and a $W$ boson in the
leading-colour approximation.

The amplitude is expressed as linear combinations of special transcendental
functions with rational function coefficients, evaluated using differential
equations and finite-field techniques, respectively. I will highlight the main
challenges of the computation, which arise from the analytic structure of the
differential equations and the high dimensionality of the phase space.

We evaluate the finite two-loop remainder on a phase-space grid, and use it to
obtain the NNLO QCD corrections to the inclusive cross section for $t\bar{t}W$
production at the LHC.

Speaker: Vsevolod Chestnov (University of Oxford)

11:50 State-of-the-art predictions for four-top production with invariant-mass threshold resummation.

Four-top production is one of the rarest Standard Model processes observable at the Large Hadron Collider, offering sensitivity to the top-Yukawa coupling, Higgs width, and beyond-Standard-Model physics. We present precise predictions for the invariant-mass distribution and total cross section using threshold resummation at next-to-next-to-leading logarithmic (NNLL) accuracy, matched to NLO in QCD+EW, including an assessment of theoretical uncertainties.

Speaker: Tommaso Saracco (Nikhef)

12:10 Top quark mass interpretation from simulation of top-flavoured mesons

The interpretation of the top quark mass measurements in terms of well-known field theory definitions has been the topic of a long-standing discussion. In this work we reconsider this issue and simulate fictitious top-flavoured mesons, whose mass can be related to any top mass definition, such as the pole mass, by means of Heavy Quark Effective Theory. We explore final-state observables for top-pair production in $e^{+}e^{-}$ and hadron collisions, and relate the top mass in standard $t\bar{t}$ events to the pole mass extracted from top-meson samples simulated with Pythia 8.3. Our results are in agreement with the expectation of an uncertainty about $200$-$300$ MeV, hence of the order of $\Lambda_{\rm QCD}$.

Speaker: Alexander Lind (INFN Laboratori Nazionali di Frascati (LNF))

12:30 Matching flavour schemes via isolation of heavy-quark mass power corrections

Higgs production in association with quarks (QQH) offers an interesting setting to study heavy-quark mass effects and the interplay between factorisation schemes in precision QCD. We present a strategy to combine the massive- (4FS in bbH) and massless schemes (5FS in bbH) consistently at the fully differential level for fixed-order QQH predictions in a general-mass variable-flavour-number scheme (GM-VFNS).

We discuss a method to isolate power corrections in the 4FS in a gauge-invariant and fully differential manner, providing the complementary ingredient to the 5FS calculation needed for a complete description of mass effects in Higgs observables. The logarithmic contributions of the massive scheme are captured through space-like Operator Matrix Elements (OMEs), while a slicing in the heavy-quark mass isolates the constant terms and validates the matching. Subtracting these from the 4FS result leaves the genuine power corrections, which are then added to the 5FS differential predictions.

We show fixed-order results for Higgs observables at second and third order in the strong coupling constant. We conclude by discussing an alternative GM-VFNS scheme based on the ACOT formalism, which provides a different organisation of mass contributions in QQH predictions.

Speaker: Christian Biello (ETHZ)

11:10 → 12:50 High-scale QCD

Conveners: Federico Buccioni (CERN), Dr Federico Sforza (University and INFN Genoa), Jennifer Roloff (Brown University (US))

11:10 Charm and bottom quark pair production cross sections at hadron colliders at next-to-next-to-leading-order accuracy

The inclusive cross sections for charm ($c\bar c$) and bottom ($b\bar b$) quark-antiquark pair production in proton-proton, proton-antiproton, and proton-nucleus collisions are studied over a wide range of center-of-mass energies, $\sqrt{s} = 10$ GeV--400 TeV. All existing data over $\sqrt{s} = 10$ GeV--14 TeV are collected and compared to calculations at next-to-next-to-leading-order (NNLO) accuracy using the new fixed-order MaunaKea open-source code for varying sets of parton distribution functions (PDFs). Relative to next-to-leading-order (NLO) predictions, the NNLO cross sections are enhanced by up to a factor of two, with the associated theoretical scale uncertainties reduced by the same amount, leading to agreement with experimental data over the full range of collision energies. The NNLO results are also compared with NLO predictions obtained within the SACOT-$m_T$ general-mass variable-flavour-number scheme. Despite still sizable theoretical and experimental uncertainties, $c\bar c$ cross section at multi-TeV energies can provide extra constraints on the gluon density at very small-x in global PDF analyses. In the bottom sector, more precise cross section measurements at low energies, $\sqrt{s} = 10$--100 GeV, can help constraint the bottom-quark pole mass.

Biblio: arXiv:2605.16019 [hep-ph]

Speaker: David d'Enterria (CERN)

11:30 Observation of W, Z, and jet production with a tagged forward proton in proton-proton collisions at √s = 13.6 TeV

We report the first observation of the production of high-transverse-momentum jets and electroweak bosons in association with a tagged forward proton in proton–proton collisions at a center-of-mass energy of 13.6 TeV. The analysis uses 2.0 fb(^{-1}) of data collected by the CMS experiment during dedicated low-pileup LHC operation in 2026. Forward protons carrying 85–97% of the beam energy are reconstructed with the CMS Precision Proton Spectrometer and associated with centrally produced W bosons, Z bosons, or multijet systems. The signal is established through the observation of significant forward–backward asymmetries of the central system with respect to the tagged-proton direction, providing direct evidence that the proton originates from the same hard interaction. The production of W and jet events with a tagged forward proton is observed with significances exceeding five standard deviations, while the Z-boson channel is observed with a significance above three standard deviations. Fiducial tagged-proton fractions are measured inclusively and differentially as functions of jet multiplicity, W-boson charge, and multijet invariant mass, extending to central-system masses above 2 TeV. The measured rates are found to be significantly larger than predictions from current hard-diffractive models, providing new constraints on the description of diffraction and color-singlet exchange at the highest momentum transfers accessible at the LHC.

Speaker: Bhawna Gomber (University of Hyderabad, India)

11:50 Recent progress on logarithmic accuracy in PanScales

This talk will present recent progress on demonstrable logarithmic accuracy in the PanScales parton shower project. It will discuss NNLL showers for colour-singlet processes with initial-state hadrons, and the extension of NNLL accuracy for event-shape-like and non-global observables to both PanGlobal and PanLocal showers, in a framework that consistently includes spin correlations. Finally, it will discuss how NLL accuracy is achieved for processes with heavy quarks in the final state.

Speaker: Keith Hamilton (University College London (GB))

12:10 Uncharted Logarithmic Structures in QCD Transverse-Energy Flow

I will discuss a new class of non-global observables defined by a veto on transverse-energy ($E_T$) flow inside an azimuthal interval $\Delta\phi$ about a chosen reference axis. Such vetoes are widely used in LHC measurements involving missing transverse momentum, yet they probe a kinematic regime whose logarithmic structure has not been explored before. We show that these observables exhibit logarithms more singular than any previously reported: both non-global logarithms (NGLs) and coherence-violating logarithms (CVLs) acquire an extra power of the large logarithm relative to standard non-global observables. I will focus on the CVL sector---computing the leading coherence-violating contribution and showing that it is enhanced from NDL to NNDL accuracy---which makes this observable an unusually sensitive probe of collinear-factorization breaking at hadron colliders. Capturing these enhanced CVLs requires resummation techniques beyond the standard non-global toolkit, which I will discuss. I will also summarize the all-orders analysis for $pp$ collisions, including analytical resummation at next-to-double-logarithmic accuracy and numerical leading-logarithmic resummation in the Veneziano limit.

Speaker: Alexander Fraley (University of Manchester)

12:30 High-precision QCD physics at FCC-ee

The electron-positron stage of the Future Circular Collider (FCC-ee) is aiming at direct and indirect searches for physics beyond the SM in a new 91-km tunnel at CERN. In addition, the FCC-ee offers unique possibilities for high-precision studies of the strong interaction in the clean environment provided by ee collisions, thanks to its broad span of center-of-mass energies, ranging from the Z pole to the top-pair threshold, and its huge integrated luminosities yielding jets from Z and W bosons decays respectively, pure gluon jets from Higgs boson decays, as well as O(2\times10^6) top quarks. In this contribution, we will summarize the impact that the FCC-ee will have on our improved knowledge of the strong force including: (i) QCD coupling determinations with permil uncertainties, (ii) ultraprecise studies of parton radiation and jet properties (ligh-quark/heavy-quark/gluon discrimination, jet substructure, etc.); and (iii) accurate scrutiny of nonperturbative QCD phenomena (color reconnection, hadronization, final-state hadron interactions,...).

Speaker: Rene Poncelet (IFJ PAN Krakow)

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 Recent results in Lambda and Ks production cross sections at LHCb

Recent LHCb measurements of the differential production cross-sections of prompt $K_S^0$ and $\Lambda$ hadrons in proton--proton collisions are presented. The production cross-sections and the $\Lambda/K_S^0$ production ratio are measured at centre-of-mass energies of $\sqrt{s}=13$ and $13.6\,\mathrm{TeV}$ as functions of rapidity and transverse momentum in the forward region. The results are compared with theoretical calculations, event-generator predictions, and previous experimental measurements.

14:20 Heavy-flavour production in heavy-ion collisions with ALICE

Heavy-ion collisions at the Large Hadron Collider (LHC) provide a unique environment for probing the properties of the quark-gluon plasma (QGP), a deconfined state of strongly interacting matter in which quarks and gluons are not bound into hadrons. Heavy quarks (charm and beauty), produced predominantly in the initial hard-scattering processes, traverse the full evolution of the medium and act as privileged probes of its characteristics.

This contribution presents the latest ALICE results on heavy-flavour production in heavy-ion collisions. Measurements of open heavy-flavour hadrons constrain the modelling of energy loss and diffusion of heavy quarks in the QGP, probing the mass dependence of parton–medium interactions. Measurements of elliptic and higher-order flow coefficients of heavy-flavour hadrons provide evidence for charm-quark thermalization and participation in the collective expansion of the medium. Quarkonium production, of both ground and excited states, is discussed in terms of colour screening and regeneration mechanisms, which are sensitive to quarkonium binding energies and the temperature of the QGP. Complementary measurements of coherent photoproduction of quarkonia in ultra-peripheral Pb-Pb collisions are also discussed as a tool to access the gluon distribution in nuclei.

These observables combined provide a comprehensive picture of heavy-quark transport, hadronisation, and quarkonium production in the QGP.

Speaker: Luigi Dello Stritto (Austrian Academy of Sciences (AT))

14:40 Heavy flavour production with SMOG2

The majority of charm quarks are produced in the initial stages of the collision. In heavy-ion collisions, this makes final-state particles containing charm quarks ideal probes of the formed medium, its effects, and its evolution. Charmonium states are among the most important probes of the deconfined QCD matter. A complete understanding of their production and interaction with the medium created in the collision is necessary to disentangle genuine hot-matter effects from cold nuclear matter effects. Furthermore, the presence of a nuclear environment may affect the hadronisation mechanism of charm
quarks, potentially leading to an asymmetry in the production of open-charm mesons. To quantify these effects, charm-hadron production must be measured in different collision systems over a wide energy range. Fixed-target collisions at LHCb, enabled by the SMOG2 system, complement studies performed in collider mode and provide access to kinematic regions not explored by other fixed-target experiments. In Run 3, the SMOG2 system has allowed for an expanded set of targets, including H2, D2, He, CH4, O2, Ne, Ar, and Xe, the former serving as a proxy for pp collisions at √sNN = 113 GeV. Here we present the first LHCb fixed-target heavy-flavour results from Run 3 and discuss the prospects for upcoming analyses aimed at improving the precision of and extending the Run 2 results. These results highlight the unique opportunities offered by the LHCb fixed-target programme
for studying quarkonium production, open-charm hadronisation, and nuclear matter effects, advancing our understanding of QCD matter under extreme conditions.

15:00 Isolating Unisolated Upsilons with Anomaly Detection in CMS Open Data

We present the first study of anti-isolated Upsilon decays to two muons (Υ→μ+μ−) in proton-proton collisions at the Large Hadron Collider. Using a machine learning (ML)-based anomaly detection strategy, we "rediscover" the Υ in 13 TeV CMS Open Data from 2016, despite overwhelming anti-isolated backgrounds. We elevate the signal significance to 6.4σ using these methods, starting from 1.6σ using the dimuon mass spectrum alone. Moreover, we demonstrate improved sensitivity from using an ML-based estimate of the multi-feature likelihood compared to traditional "cut-and-count" methods. Our work demonstrates that it is possible and practical to find real signals in experimental collider data using ML-based anomaly detection, and we distill a readily-accessible benchmark dataset from the CMS Open Data to facilitate future anomaly detection developments.

Speaker: Radha Mastandrea

15:20 The ALADDIN experiment at LHC

ALADDIN (An LHC Apparatus for Direct Dipole moments INvestigation, https://aladdin.web.cern.ch/) is a proposed compact fixed-target experiment at the LHC, designed to enable precise measurements of charm baryon electromagnetic dipole moments. The experiment leverages an innovative storage-ring layout that redirects protons from the beam halo onto a solid target, coupled with a bent crystal. This setup produces forward-boosted charm baryons, which are then channeled through the crystal. By exploiting spin precession induced by the channelling effect in the bent crystal, ALADDIN aims to measure both the magnetic and electric dipole moments through an analysis of the polarization of decaying charm baryons. The experimental apparatus consists of a 4.4 m-long spectrometer and a 20 m-long RICH detector for particle identification. It is designed for installation in the LHC Insertion Region 3 during Long Shutdown 3 (and onwards), requiring no civil engineering and having minimal impact on LHC operations, with data-taking planned for Run 4+5. A proof-of-principle test at the LHC, TWOCRYST (https://twocryst.web.cern.ch/), has concluded several successful dedicated machine development runs in 2025 and 2026 ,before LS3. TWOCRYST demonstrated the feasibility of the concept and detailed data analysis is ongoing. The experiment’s Letter of Intent has been submitted to the LHCC (https://cds.cern.ch/record/2905467), which has approved the collaboration to proceed with a technical proposal in 2026-2027.

Speaker: Paolo Gandini

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 Recent Heavy-Flavor Spectroscopy and Rare Decay Results from ATLAS

This talk presents recent ATLAS results in heavy-flavor spectroscopy and rare decay searches. Highlights include studies of excited Bc meson states and resonance structures in the J/ψψ(2S) system, providing new insight into heavy-quark bound states and exotic hadron spectroscopy. Selected searches for rare decays are also discussed, extending the sensitivity of ATLAS to physics beyond the Standard Model.

Speaker: ATLAS Collaboration

16:20 Recent results of hadron spectroscopy with the amplitude-analysis techinque

Hadron spectroscopy plays a central role in deepening our understanding of the low-energy and non-perturbative regime of the strong interaction. Excited hadrons can be produced in heavy-hadron decays when kinematically allowed. In such processes, amplitude analysis provides a powerful technique to disentangle contributions from different resonances and to determine their spin-parity quantum numbers by exploiting angular-distribution information. This talk will cover recent results in hadron spectroscopy obtained using amplitude-analysis techniques at LHCb.

16:40 Excited heavy mesons and exotics from lattice QCD

In recent years there has been a lot of progress in studying excited and exotic hadrons, resonances and scattering using first-principles lattice QCD calculations. I will discuss a selection of work on charm and charmonium-like mesons such as results relevant for the exotic $T_{cc}$, $T_{cs}$ and $T_{c\bar{s}}$ observed by LHCb, the $D^{*}_{0}(2300)$ and enigmatic $D^{*}_{s0}(2317)$ charm mesons, and scalar and tensor charmonium resonances.

Speaker: Christopher Thomas (University of Cambridge)

17:00 Recent results in seaches for tetraquark states in CMS

The spectroscopy of exotic hadrons provides a unique opportunity to investigate the dynamics of Quantum Chromodynamics (QCD) in the non-perturbative regime. The large data samples collected by the CMS experiment during LHC Run 2 and Run 3 have enabled high-precision studies of multiquark candidates in several heavy-quark systems.

Recent CMS measurements have established the existence of multiple fully charmed tetraquark candidates in the (J/ψ,J/ψ) invariant-mass spectrum. The analysis reveals three resonant structures, (X(6600)), (X(6900)), and (X(7100)), with significances exceeding the observation threshold, and provides evidence for quantum interference effects among the resonances, offering new insight into the spectroscopy and internal structure of fully heavy multiquark states.

In addition, CMS has recently reported the observation of a resonant structure in the (Υ(1S)φ(1020)) final state, opening new investigations into study exotic states containing both beauty and strangeness. This measurement extends the experimental exploration of tetraquark spectroscopy into a previously unexplored sector and provides valuable input for theoretical descriptions of multiquark dynamics.

Together, these measurements demonstrate the outstanding potential of the CMS experiment for precision spectroscopy and establish a new benchmark for understanding the spectrum of exotic hadrons in high-energy proton--proton collisions.

Speaker: Adriano Di Florio (Centre National de la Recherche Scientifique (FR))

17:20 All-charm tetraquarks at hadron colliders: A high-precision fragmentation perspective

We present a systematic study of all-charm tetraquark fragmentation in high-energy hadronic collisions within a heavy-flavor fragmentation framework in QCD. As part of this program, we construct the TQ4Q2.0 fragmentation functions by consistently incorporating, for the first time, all leading-power partonic fragmentation channels. The calculation combines updated NRQCD-inspired initial-scale inputs with threshold-aware DGLAP evolution implemented through the Heavy-Flavor NonRelativistic evolution (HF-NRevo) scheme. A replica-based uncertainty-quantification strategy incorporating missing-higher-order and long-distance matrix-element uncertainties is implemented, leading to evolved fragmentation-function grids released in LHAPDF6 format. This work promotes a precision-QCD and collider-oriented description of multiquark production dynamics, providing a systematic framework relevant to the interpretation of recent all-charm tetraquark observations at the LHC and to future investigations at next-generation colliders.

Speaker: Dr Francesco Giovanni Celiberto (UAH Madrid)

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 Overview of ALICE results

Speaker: Maximiliano Puccio (CERN)

12:30 Status of the EIC

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