Name: QCD Evolution 2026
Start: 2026-05-11T09:00:00+02:00
End: 2026-05-15T19:00:00+02:00
Location: El Escorial

QCD Evolution 2026

from Monday, 11 May 2026 (09:00) to Friday, 15 May 2026 (19:00)

Monday, 11 May 2026

10:15 Welcome
Welcome
10:15 - 10:30
10:30 First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton - Alexei Prokudin (PSU Berks and Jefferson Lab)
First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton
- Alexei Prokudin (PSU Berks and Jefferson Lab)
10:30 - 11:00
We present the first simultaneous global QCD analysis of unpolarized transverse momentum dependent (TMD) and collinear parton distribution functions (PDFs) in the proton. Our study incorporates data from deep-inelastic scattering, Drell-Yan, inclusive weak boson, W+ charm, and jet production involving PDFs, as well as TMD Drell-Yan and Z-boson production data from fixed target and collider experiments sensitive to both TMD and collinear distributions. The analysis is performed at next-to-next-to-leading logarithmic accuracy for QCD resummation in TMD observables and next-to-leading order for observables described in collinear factorization. The combined analysis improves knowledge of both TMD and collinear PDFs, particularly in the sea-quark sector, providing a consistent simultaneous description of the aforementioned observables.
11:00 NNNLO QCD corrections to Semi-Inclusive Deep-Inelastic Scattering - Haitao Li (Shandong University)
NNNLO QCD corrections to Semi-Inclusive Deep-Inelastic Scattering
- Haitao Li (Shandong University)
11:00 - 11:30
Driven by the high-precision demands of the upcoming Electron-Ion Collider (EIC), this talk presents the computation of the next-to-next-to-next-to-leading order QCD corrections to the semi-inclusive deep-inelastic scattering (SIDIS) cross section. To systematically handle the intricate infrared singularities at this order, we introduce a novel two-dimensional transverse-momentum subtraction formalism. I will outline this theoretical framework and discuss the phenomenological impact of the corrections on key kinematic observables. Based on the works, arXiv:2602.06364 and arXiv:2603.29673
11:30 An overview of parton and transverse distribution functions and the quark fragmentation function - Bruno El-Bennich (Universidade Federal de São Paulo)
An overview of parton and transverse distribution functions and the quark fragmentation function
- Bruno El-Bennich (Universidade Federal de São Paulo)
11:30 - 12:00
I will present an overview of parton and transverse distribution functions and their relation to an elementary quark fragmentation function within a functional approach to QCD. Recent results on light and charm quark jet fragmentation functions will be presented.
12:00 Coffe break

12:00 - 12:30
12:30 The $\gamma^* \to \eta\gamma$ and $\gamma^*\to \eta'\gamma$ form factors to NNLO accuracy - Vladimir Braun (University of Regensburg)
The $\gamma^* \to \eta\gamma$ and $\gamma^*\to \eta'\gamma$ form factors to NNLO accuracy
- Vladimir Braun (University of Regensburg)
12:30 - 13:00
We use conformal symmetry to calculate the NNLO anomalous dimension matrix (three loops) for flavor-singlet axial-vector QCD operators for spin N ≤ 8 from a set of gauge-invariant two-point correlation functions. Combining this result with the recent calculation of the two-loop coefficient functions, we carry out the calculation of the $\gamma^* \to \eta\gamma$ and $\gamma^*\to \eta'\gamma$ form factors at large timelike momentum transfers to the NNLO accuracy in perturbative QCD.
13:00 Effect of TMD evolution on the Sivers Asymmetry at EIC - Asmita Mukherjee
Effect of TMD evolution on the Sivers Asymmetry at EIC
- Asmita Mukherjee
13:00 - 13:30
In this talk, I'll discuss the effect of TMD evolution on the Sivers asymmetry in almost back-to-back production J/psi and jet and J/psi and photon at the upcoming EIC.
13:30 QCD Studies with the F2A structure function - Narbe Kalantarians (Virginia Union University)
QCD Studies with the F2A structure function
- Narbe Kalantarians (Virginia Union University)
13:30 - 14:00
Using charged lepton and neutrino scattering data in the deep-inelastic region, we have used the F2A structure function for a number of studies relevant to QCD. These data reside considerably in the regime of particular relevance to studies of the EMC Effect. Recently, we have been looking at (anti)shadowing region for the envisioned 20-22 GeV kinematic region. This talk will cover our work including comparative studies between charged lepton and neutrino data, EMC ratios studies with F2n, as well as the recent study in the (anti) shadowing region.
14:00 Lunch

14:00 - 15:30
15:30 Session A1: TMD in multiple observables
TMD in multiple observables
15:30 - 17:30
Contributions

15:30 DUNE as a neutrino DIS experiment - Ángel Felipe Ballesteros (University of the Basque Country, Spain (UPV-EHU))

15:50 Quark transverse-momentum effects and the W boson mass - Sara Pontina (University of Turin)

16:10 First extraction of collinear unpolarised $\Lambda$ hyperon fragmentation functions at next-to-next-to-leading order in perturbative QCD - Alessia Bongallino (University of the Basque Country)

16:30 Next-to-leading Order QCD Factorization for Energy Flow in Electron-Ion Collisions at Twist 4 - Omar Elgedawy (CPHT, Ecole Polytechnique)

16:50 In medium evolution of the energy-energy correlators - Bianka Mecaj (Los Alamos National Lab)

17:10 Parton distribution and fragmentation functions with massive gluons - Gustavo Barbosa Bopsin (Universidade Estadual Paulista / Ecole Polytechnique)
17:30 Coffe break

17:30 - 18:00

18:00 T: Walk to the Silla de Felipe II
Walk to the Silla de Felipe II
18:00 - 20:00
Tuesday, 12 May 2026
10:00 Transverse momentum measurements in SIDIS with jets at next-to-leading power - Max Jaarsma (JGU Mainz)
Transverse momentum measurements in SIDIS with jets at next-to-leading power
- Max Jaarsma (JGU Mainz)
10:00 - 10:30
We present a factorization formula for the e + h → e + jet + X cross section at small transverse momenta up to next-to-leading power (NLP), derived using the background field method (BFM) with explicit inclusion of soft modes. We discuss the relation between soft modes and overlap subtractions at NLP, showing that the inclusion of soft modes enables a definition of twist-3 operators with properly subtracted rapidity and endpoint divergences. We also derive the effective current operator at NLP and identify additional structures compared to previous approaches based on soft-collinear effective theory and the BFM without soft modes. Nevertheless, for the hadronic tensor, we find agreement at the perturbative order that we are working at, and identify a condition that needs to be satisfied for this agreement to extend to higher orders. Furthermore, we construct the most general form factors for this process, taking into account the polarization of the initial states. These involve perturbatively-calculable jet functions, opening a path to precise determinations of twist-3 hadronic distributions. Finally, our formalism is illustrated with phenomenological results for a specific azimuthal asymmetry, whose leading-logarithmic contribution depends solely on a twist-3 hadronic distribution and a twist-2 jet function.
10:30 Collins effect in pion-in-jet production in hadron-hadron and lepton-hadron collisions - Umberto D'Alesio (University and INFN Cagliari)
Collins effect in pion-in-jet production in hadron-hadron and lepton-hadron collisions
- Umberto D'Alesio (University and INFN Cagliari)
10:30 - 11:00
We present a phenomenological analysis of the Collins azimuthal asymmetries for pion-in-jet production in polarized $pp$ and $ep$ collisions within a TMD approach, adopting a collinear configuration for the initial state. To this aim, we employ the transversity and the Collins fragmentation functions as extracted from semi-inclusive DIS and $e^+ e^-$ annihilation processes. After comparing our estimates for $pp$ collisions with recent STAR data, we give predictions for lepton-proton collisions for the future Electron-Ion Collider, taking into account the contribution of quasireal photon exchange. We then show how this study could represent a further step in testing the hypothesis of the universality of the Collins function as well as of the TMD factorization for such processes.
11:00 A neural-network extraction of TMD distributions - Valerio Bertone (CEA Saclay)
A neural-network extraction of TMD distributions
- Valerio Bertone (CEA Saclay)
11:00 - 11:30
11:30 Coffe break

11:30 - 12:00
12:00 Interpolation between Sudakov and BFKL rapidity evolutions for TMD factorization at small x - Ian Balitsky (JLab/ODU)
Interpolation between Sudakov and BFKL rapidity evolutions for TMD factorization at small x
- Ian Balitsky (JLab/ODU)
12:00 - 12:30
Within the framework of rapidity-only small-$x$ TMD factorization, the evolution with respect to the rapidity cutoff is governed initially by Sudakov double-logarithmic evolution, followed by single-logarithmic BFKL/BK evolution. The evolution equation proposed in this paper correctly reproduces both the Sudakov and BFKL limits and provides a consistent interpolation between these two regimes.
12:30 The Longitudinal Unpolarized Structure function in SIDIS: from small to large P_T - Leonard Gamberg (Penn State University Berks)
The Longitudinal Unpolarized Structure function in SIDIS: from small to large P_T
- Leonard Gamberg (Penn State University Berks)
12:30 - 13:00
A unified description of the transverse-momentum spectrum in semi-inclusive deep-inelastic scattering (SIDIS) requires consistent matching between the low-$P_{hT}$ TMD regime and the high-$P_{hT}$ collinear regime. While this is well established at leading power for unpolarized structure functions, discrepancies arise at subleading power, where contributions may be phenomenologically significant and impact the extraction of universal TMDs. We present a systematic study of longitudinal photon contributions within a unified framework connecting these regimes. Analyzing their behavior across the matching region, where resummed TMD dynamics transitions to fixed-order collinear factorization, we quantify their impact on unpolarized cross sections. We further investigate the longitudinal structure function $F_{UU,L}$ and the ratio $R_{\mathrm{SIDIS}}=F_{UU,L}/F_{UU,T}$ as probes of subleading dynamics. Our results clarify subleading-power effects in matching and provide constraints for global TMD analyses.
13:00 Transverse momentum dependence in antiproton production from cosmic rays - Andrea Signori (University of Turin and INFN)
Transverse momentum dependence in antiproton production from cosmic rays
- Andrea Signori (University of Turin and INFN)
13:00 - 13:30
We present predictions for antiproton production cross sections in proton–proton collisions, which describe the interaction of cosmic rays with the interstellar medium. The aim of the project is to test a claimed excess in the production of secondary vs primary antiprotons in pp collisions against the QCD factorization framework. We quantify the uncertainties of the involved cross sections in terms of PDFs, FFs, and missing higher orders and highlight the importance of understanding the low transverse momentum region for these specific observables.
13:30 Factorizing quarkonium production matrix elements using effective field theory - Ivan` Vitev (LANL)
Factorizing quarkonium production matrix elements using effective field theory
- Ivan` Vitev (LANL)
13:30 - 14:00
We use effective field theory to factorize production matrix elements that appear in the NRQCD framework for quarkonium cross sections. By applying a Hubbard–Stratonovich transformation and appropriate field redefinitions, we show that the soft and ultrasoft sectors of NRQCD can be decoupled from the heavy quark and antiquark fields in a hybrid vNRQCD/pNRQCD Lagrangian at leading order in the velocity power-counting. This enables us to re-factorize quarkonium production matrix elements in terms of matrix elements of color-singlet composite fields, which we can write as the wave-function at the origin, and state independent vacuum correlators of chromo-electric and chromo-magnetic gluon fields. This approach verifies powerful relationships between the LDMEs of different S-wave quarkonia originally derived using pNRQCD. Additionally, it allows us to derive new relationships for the production matrix elements used in the transverse momentum dependent factorization (TMD) framework, known as TMD soft transition functions, providing a much stronger set of constraints on these nonperturbative operators. This work significantly advances our understanding of quarkonium production, particularly at small transverse momentum, and should pave the way to address longstanding tensions between theory and experiment on quarkonium production cross sections at small pT
14:00 Lunch

14:00 - 15:30
15:30 Session B1: SIDIS: jets, mesons, quarkonia and data
SIDIS: jets, mesons, quarkonia and data
15:30 - 17:30
Contributions

15:30 On the reconstruction of SIDIS observables in the Breit frame - Richard Whitehill (Old Dominion University)

15:50 Hadroproduction of Pseudoscalar Heavy-Quarkonium Mesons via NRFF1.0 - Francesca Lonigro (UAH Madrid)

16:10 Matching relations for gluon TMDs up to one-loop accuracy - Alessio Carmelo Alvaro (University of Pavia and INFN Pavia)

16:30 TMD from dijet production in SIDIS - Patricia Andrea Gutiérrez García (Universidad Complutense de Madrid)

16:50 Tomography of nucleon through dimeson photoproduction - David PEREZ (IJCLab, Orsay)

17:10 Resummed azimuthal decorrelation and transverse momentum imbalance of dijets at the LHC - Rong-Jun Fu (Fudan University)
17:30 Coffe break

17:30 - 18:00
18:00 Session A2: Higher perturbative orders, SIDIS
Higher perturbative orders, SIDIS
18:00 - 19:00
Contributions

18:00 The DIS dipole picture cross section in exact kinematics - Magnus Bertilsson (University of Jyväskylä)

18:20 Rapidity Dependent Beam Functions at NNLO - Thomas Clark (University of Manchester)

18:40 NNLO QCD corrections to hadron production in DIS at finite transverse momentum - Shen Fang (Fudan University)
Wednesday, 13 May 2026

10:00 Excursion

10:00 - 14:00

14:00 Lunch

14:00 - 15:30
15:30 Session C1: Lattice and tools
Lattice and tools
15:30 - 17:30
Contributions

15:30 Fragmentation functions on quantum computers - Juan José Gálvez Viruet (Univ. Complutense de Madrid)

15:50 Pionic gluons from global QCD analysis of experimental and lattice data - William Good (Michigan State University)

16:10 Connecting Baryon Light-Front Wave Functions to Quasi-Transverse-Momentum-Dependent Correlators in Lattice QCD - Andrea Schiavi

16:30 Score-based diffusion models for lattice gauge theory and prospects for TMD/FF reconstruction - Bao-Dong Sun (Ruhr University Bochum)

16:50 Quasi Parton Distribution Functions in Covariant Quark Models - Asli Tandogan (University of Connecticut)

17:10 qT/Q corrections for unpolarized Drell-Yan in TMD factorization - Arturo Arroyo Castro (Universidad Complutense de Madrid)
17:30 Coffe break

17:30 - 18:00
18:00 Session A2: Higher perturbative orders, resummations
Higher perturbative orders, resummations
18:00 - 18:40
Contributions

18:00 NNLO extraction of Unpolarized Di-hadron fragmentation Functions - LUCA POLANO (University of Pavia, Istituto Nazionale di Fisica Nucleare)

18:20 From Collinear to TMD Distributions in the Large-x Regime - Óscar del Río García (Universidad Complutense Madrid)
18:40 Session C2
18:40 - 19:00
Contributions

18:40 Gluon production at small-x - José Garrido (Federico Santa María Technical University)
Thursday, 14 May 2026
10:00 All-Orders Evolution of Parton Distributions - José Rodríguez Quintero (Universidad de Huelva)
All-Orders Evolution of Parton Distributions
- José Rodríguez Quintero (Universidad de Huelva)
10:00 - 10:30
Parton distribution functions (PDFs) are defining expressions of hadron structure. Exploiting the role of effective charges in quantum chromodynamics, an algebraic scheme is described which, given any hadron's valence parton PDFs at the hadron scale, delivers predictions for all its PDFs (unpolarized and polarized) at any higher scale. The scheme delivers results that are largely independent of both the value of the hadron scale and the pointwise form of the charge; and, inter alia, enables derivation of a model-independent identity that relates the strength of the hadron's gluon helicity PDF, to that of the analogous singlet polarized quark PDF and valence quark momentum fraction.
10:30 The Fate of Ultra-Collinear Modes in On-Shell Massive Sudakov Form Factors - Jacob Schönleber (Technical University Munich)
The Fate of Ultra-Collinear Modes in On-Shell Massive Sudakov Form Factors
- Jacob Schönleber (Technical University Munich)
10:30 - 11:00
Individual multi-loop diagrams for the massive Sudakov form factor contain an infinite tower of ultra-collinear momentum regions. We show that, for the on-shell form factor in QCD, these contributions cancel to all orders as a consequence of gauge invariance, so the leading-power SCETII factorization formula is unchanged. Using the η rapidity regulator, we compute the soft function and the massive jet function of the quark and gluon Sudakov form factors through two loops and resum logarithms at NNLL accuracy, including hierarchies of fermion masses. We also show that with a gauge-boson mass regulator, the infinite tower of modes is truncated and ultra-collinear and ultra-soft modes become manifest and factorize explicitly, providing a direct EFT derivation of the regulated infrared dependence.
11:00 Azimuthal asymmetries in lepton and heavy-quark pair production in UPCs - Daniel Boer (University of Groningen)
Azimuthal asymmetries in lepton and heavy-quark pair production in UPCs
- Daniel Boer (University of Groningen)
11:00 - 11:30
Azimuthal modulations in electron-positron pair production in ultraperipheral collisions (UPCs) of gold ions have been observed by the STAR collaboration at RHIC. The modulations arise from the collisions of unpolarized and polarized photons emanating from the highly charged ions. In this talk the theoretical description in terms of Generalized Transverse Momentum Dependent parton distributions (GTMDs) of photons inside ions will be discussed. From this description it can be understood that in principle harmonics of all (even) orders will arise. From a model that is able to describe the RHIC data, it furthermore follows that the results depend considerably on the mass of produced particles. The most promising channels to experimentally demonstrate this in UPCs at RHIC and LHC will be discussed. This talk is based on work done together with Cristian Pisano and Luca Maxia, published in JHEP01(2025)076.
11:30 Coffe break

11:30 - 12:00
12:00 Probing TMDs through double quarkonium production in hadronic collisions - Cristian Pisano
Probing TMDs through double quarkonium production in hadronic collisions
- Cristian Pisano
12:00 - 12:30
Transverse momentum dependent parton distribution functions (TMDs) encode essential information on the transverse motion of partons inside nucleons, as well as their spin-orbit correlations. In this talk I will show how, by looking at the azimuthal asymmetries in the inclusive production of pairs of vector quarkonia, one can probe different TMDs. In particular, quark and antiquark TMDs could be accessed in pion-proton scattering at the COMPASS and AMBER experiments at CERN, where the contributions of gluons is negligible. The impact of the present and future fixed-target experiments at the LHC (SMOG, LHCspin) on this kind of studies will be discussed as well. This work is mainly based on work done together with Carlo Flore, published in JHEP 02 (2026) 085.
12:30 Evolution and Transversely Polarized processes: a Sivers function determination - Filippo Delcarro (INFN Torino)
Evolution and Transversely Polarized processes: a Sivers function determination
- Filippo Delcarro (INFN Torino)
12:30 - 13:00
13:00 Nuclear corrections to Deeply Virtual Compton Scattering - John Terry (LANL)
Nuclear corrections to Deeply Virtual Compton Scattering
- John Terry (LANL)
13:00 - 13:30
We present a systematic study of nuclear-enhanced power corrections in deeply virtual Compton scattering (DVCS) on nuclear targets, extending techniques developed for inclusive deep inelastic scattering to exclusive processes. Using a light-cone operator product expansion and the method of regions, we identify coherent final-state interactions of the struck quark as the dominant source of higher-twist nuclear modifications. These contributions can be resummed to all orders, leading to compact expressions for the DVCS amplitude characterized by a single nonperturbative scale and enhanced by nuclear size effects. Our formalism provides a controlled framework for quantifying nuclear modifications to generalized parton distributions at small momentum transfer and moderate photon virtuality. The results establish a direct theoretical connection between inclusive DIS dynamics and exclusive nuclear observables, with important implications for three-dimensional imaging of nuclei at future facilities such as the Electron–Ion Collider.
13:30 Session A1
13:30 - 14:00
Contributions

13:30 Coherence-violating logarithms - Andrea Banfi (University of Sussex)
14:00 Lunch

14:00 - 15:30
15:30 From Sub-eikonal DIS to Quark Distributions and their High-Energy Evolution - Giovanni Antonio Chirilli (National Centre for Nuclear Research (NCBJ), Warsaw)
From Sub-eikonal DIS to Quark Distributions and their High-Energy Evolution
- Giovanni Antonio Chirilli (National Centre for Nuclear Research (NCBJ), Warsaw)
15:30 - 16:00
I show that the first sub-eikonal correction reproduces the standard quark and helicity light-ray operator structure of DIS and, in the inclusive limit, recovers the corresponding distributions at nonzero Bjorken $x_B$. I then derive dipole-form expressions for the corrections to $F_L$, $F_T$, and $g_1$, and identify the relevant operator combinations in the singlet and non-singlet sectors. The operator basis thus obtained is naturally organized in terms of dipole operators that vanish in the zero-size limit, making unitarity and small-dipole behavior manifest. I further show that the logarithmic singularities of the sub-eikonal correction to the dipole structure functions are precisely the one-loop evolution of the quark and helicity light-ray operators. In the double-logarithmic approximation, I recover the Kirschner-Lipatov exponent and clarify its relation to previous small-$x_B$ helicity resummations.
16:00 Session B2: GPD
GPD
16:00 - 16:40
Contributions

16:00 Computation of NLO evolution equations of GPDs in the lightcone gauge - Oskar Grocholski (IRFU/CEA, France)

16:20 Constraining QCD energy-momentum tensor via dispersion relations - Victor Martinez Fernandez (IRFU/CEA (France) and CFNS (USA))
16:40 Session B2
16:40 - 17:20
Contributions

16:40 Unpolarized twist-two GPDs and the role of different IR regulators - Ignacio Castelli (Temple University)

17:00 A Finite Element Method Analysis of Shadow Ambiguities in Generalized Parton Distributions - Marija Čuić (Irfu, CEA, Université Paris-Saclay/Aidas)
17:20 Coffe break

17:20 - 17:50
17:50 Session C2
17:50 - 18:30
Contributions

17:50 Conformal moments of the two-loop coefficient functions in DVCS - Patrick Gotzler

18:10 Momentum-Space BK Evolution with RG-Improved Resummation and Kinematical Constraints - Wanchen Li (Fudan University)
18:30 Session B3
18:30 - 19:10
Contributions

18:30 TMD factorization for massive quark production in photon-nucleus collisions - Patricia Gimeno-Estivill (University of Jyväskylä)

18:50 Extraction of quantum interference within the proton - Guillermo Portela Maller (Universidad Complutense de Madrid)
21:00 Workshop Dinner: Restaurante La Rueda, Av. de la Constitución, 41, 28280 El Escorial
Workshop Dinner: Restaurante La Rueda, Av. de la Constitución, 41, 28280 El Escorial
21:00 - 00:00
Friday, 15 May 2026
10:00 A Pixel-Based Bayesian Approach for Model-Independent TMD Reconstruction - Marco Zaccheddu (Jefferson Lab)
A Pixel-Based Bayesian Approach for Model-Independent TMD Reconstruction
- Marco Zaccheddu (Jefferson Lab)
10:00 - 10:30
The extraction of Transverse Momentum Dependent distributions (TMDs) from experimental data is a fundamental inverse problem in hadronic physics. Traditionally, this challenge is addressed by assuming specific analytical functional forms. However, these choices can introduce a parameterization bias and limit our ability to explore the full uncertainty of the results. In this talk, we present a novel "Pixel-Based" approach that treats TMD imaging as a discrete reconstruction task. By formulating the TMD convolutions through discrete tensor algebra, we treat each pixel in the impact parameter $b_T$-space as a stochastic variable. This framework allows for a non-parametric reconstruction of the TMDs within a robust Bayesian inference scheme. To efficiently sample the high-dimensional posterior distribution of the pixels, we employ modern Machine Learning techniques, specifically Normalizing Flows. We focus on a systematic study of the resolution limits and stability of this inversion process. By analyzing the resolution matrix in $b_T$-space, we quantify how different kinematic coverages and experimental precision constrain the underlying 3D structure. This work serves as a proof-of-concept for a low-bias imaging framework, establishing a solid foundation for model-independent extractions of nucleon structure.
10:30 Fast next-to-leading order evolution of generalized parton distributions - Adam Freese (Center for Nuclear Femtography)
Fast next-to-leading order evolution of generalized parton distributions
- Adam Freese (Center for Nuclear Femtography)
10:30 - 11:00
11:00 Digging into the deep infrared with TMDs - Andrea Simonelli (Jefferson Lab and ODU)
Digging into the deep infrared with TMDs
- Andrea Simonelli (Jefferson Lab and ODU)
11:00 - 11:30
Extracting information on the three-dimensional structure of hadrons from transverse-momentum data is a challenging task, as it requires disentangling well-controlled perturbative contributions from genuinely non-perturbative effects, which are unavoidably influenced by phenomenological assumptions. This subtle interplay often obscures the interpretation of phenomenological analyses, even when they provide an accurate description of experimental data. In this talk, I present a systematic procedure to analytically continue perturbative calculations into the deep infrared region, below the 1–2 GeV scale. I identify two primary sources of non-perturbative effects: the low-energy behavior of the strong coupling and that of the parton distribution functions. This framework turns transverse-momentum-dependent observables into a privileged probe of strong interactions in a poorly understood regime, offering novel insights into the strong coupling and PDFs where they are least constrained.
11:30 Coffe break

11:30 - 12:00
12:00 The Cahn Effect and Equation of Motion Relations - Owen Page (Pennsylvania State University)
The Cahn Effect and Equation of Motion Relations
- Owen Page (Pennsylvania State University)
12:00 - 12:20
I investigate proton structure through the subleading observable called the Cahn effect. Equation of motion relations constrain the TMDs in the observable and relate them to leading power TMDs. I calculate the relevant functions and verify the equation of motion relation at LO and NLO in the strong coupling. In the calculation I show the cancelation of rapidity divergences using a novel regulator associated with the lightcone propagator. These calculations are necessary to study the large qT matching, particularly in the context of the independence of the observable on rapidity divergent terms.
12:20 Session C2
12:20 - 13:20
Contributions

12:20 Order statistics for multijet events - Dario Vaccaro (LIP Lisboa)

12:40 Rapidity regulators for low x QCD - Guillaume Beuf (National Centre for Nuclear Research (NCBJ), Warsaw)

13:00 QCD–QG Duality and Discrete BFKL Evolution in Multi-Regge Kinematics - Josep Rubi Bort (IFT)
13:30 Lunch

13:30 - 15:30