Joint ECFA-NuPECC-APPEC Activity Workshop "Synergies between the EIC and the LHC"

14 Dec 2023, 08:00 → 15 Dec 2023, 20:00 Europe/Berlin

Auditorium (DESY, Hamburg)

Daniel Boer (University of Groningen), Pasquale DI Nezza (LNF, Frascati and CERN), Maria Vittoria Garzelli (None)

A Joint ECFA-NuPECC-APPEC activity (http://www.nupecc.org/jenaa/) on the topic of exploring the synergies between the EIC and the LHC has recently started. For the Expression of Interest, see https://indico.ph.tum.de/event/7004

This Workshop, taking place in person, follows the kick-off meeting held at CERN in June 2022 (https://indico.ph.tum.de/event/7014/) and aims to continue the discussion and promote further fruitful exchanges between the theoretical and experimental communities involved in LHC, EIC, and astroparticle physics. 

In the days before this Workshop, the XVI Meeting of the Physics at the Terascale Alliance will also take place in the same venue. For registrations to that Workshop, please visit https://indico.desy.de/event/41133/

Link to the JENAA EoI

link to the kick-off meeting

Thursday 14 December

08:30 → 08:50 Registration

08:50 → 09:00 Introduction to the Workshop

Speaker: The Organizers

synergies.pdf

09:00 → 09:30 Proton PDFs and connection between large- and small-x.

Speaker: Emanuele Nocera

NOCERA_Hamburg (1).pdf

09:30 → 10:00 alpha_S present status and perspectives

Speaker: Klaus Rabbertz (KIT)

alpha-s-Status_Joint-ENA-Workshop_Synergies-EIC-LHC_20231214.pdf

10:00 → 10:30 The electron-ion collider: A collider to unravel the mysteries of visible matter

Speaker: Elke-Caroline Aschenauer (BNL)

eca.EIC-LHC.v2.pptx

10:30 → 11:00 Coffee Break & Group Photo

11:00 → 11:30 LHC prospects and complementarity with EIC physics

Speaker: Nestor Armesto Perez (Universidade de Santiago de Compostela, Spain)

Armesto_JointEICLHC.pdf

11:30 → 12:00 LHCb Fixed Target results

Speaker: Kara Mattioli (LLR Ecole polytechnique)

LHCb Fixed Target Results Mattioli.pdf

12:00 → 12:30 Energy-energy correlators at the LHC and EIC

Jets produced in high energy collisions offer an excellent QCD laboratory. Jet substructure encodes QCD dynamics ranging from the initial partonic shower in the weakly coupled limit to hadronization in the strongly coupled, non-perturbative, regime. Energy correlators, which measure statistical correlations of the energy flux within a jet, are a means to separate the different scales. Defined as the energy-weighted cross-section of particle pairs inside jets, energy-energy correlators provide a calibrated probe of the scale dependence of QCD dynamics in vacuum, where the scale is controlled by the angular distance of the pairs.
As a function of pair distance, energy correlators reflect the perturbative regime at large angular distance and non-perturbative physics at small angular distance. The separation allows us to probe the dynamics of jet formation and to separate the confinement process. I will present energy-energy correlators in inclusive jets in pp collisions at the LHC, and discuss the perturbative and hadronic regions, as well as the transition between them, which corresponds to the confinement process. I will also show how this observable can be used in eA collisions at the future EIC to study the jet-medium interaction as a function of nuclear size.

Speaker: Barbara Jacak (UC Berkeley and LBNL)

LHC_EIC_EEC_jacak.pdf

LHC_EIC_EEC_jacak.pptx

12:30 → 13:00 Jet substructure: experimental opportunities at LHC and EIC

Speaker: Leticia Cunqueiro (University Sapienza Rome)

Desy_synergies_Cunqueiro.pdf

13:00 → 14:15 Lunch Break

14:15 → 14:45 Energy upgrade plans at Jefferson Lab

Speaker: Patrizia Rossi (JLab)

Rossi_DESY_indico.pdf

14:45 → 15:15 Status and Prospects of the Electron-Ion Collider project in China

Speaker: Yutie Liang

EicC_talk_upload_20231214164223.pdf

15:15 → 15:45 Review on TMDs

Speaker: Alexey Vladimirov (Regensburg University)

DESY2023.pdf

15:45 → 16:15 3-loop heavy flavor corrections to DIS

A survey is given on the 3-loop unpolarized and polarized heavy flavor corrections to DIS with reference to the kinematics at HERA, LHC and EIC.

Speaker: Johannes Bluemlein (DESY)

HH23.pdf

16:15 → 16:45 Coffee Break

16:45 → 18:50 Proton and nuclear PDFs

16:45 Towards the evolution of the Parton Distribution Functions to 1% accuracy

Precision physics, both at the LHC and at the EIC, requires to control the evolution of the Parton Distribution Functions to 1% accuracy. To achieve this target, we must compute the splitting kernels of the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equations to four loops in QCD. Recently, there has been significant progress towards this goal. I report the results obtained in the framework of the operator product expansion and discuss future challenges.

Speaker: Giulio Falcioni (University of Zuerich)

falcioni.pdf

17:10 MSHT20aN3LO - Approximate N3LO PDFs and theoretical uncertainties

We consider the extension of the MSHT20 PDFs to approximate N3LO order. We describe the inclusion of the known N3LO information and the parameterisation of the remaining missing N3LO contributions, as well as the determination of the theoretical uncertainties from missing pieces and their interpretation. We then examine the impact on the PDFs as well as on predicted cross-sections. Finally, if time allows we will provide an update on further developments and added datasets, including a study on the impact of the EIC on the PDFs.

Speaker: Thomas Cridge (T (Phenomenology))

MSHT20aN3LO_talk_DESY_Dec23_new.pdf

17:35 Approximate N3LO Parton Distributions with the NNPDF framework

We extend the existing next-to-next-to-leading (NNLO) NNPDF sets of parton distributions to approximate next-to-next-to-next-to-leading N3LO, as required by the recent availability of an increasing number of computations of scattering processes at this order.
Given the lack of full knowledge of the N3LO splitting functions, we construct an approximation to them which includes all the available partial information from fixed order computations and from resummation. We include known N3LO corrections to deep-inelastic scattering and Drell-Yan production. We account for the partial knowledge of N3LO terms, and for their complete lack of knowledge for some processes, through a theory covariance matrix formalism. We assess the perturbative stability of the resulting PDFs and study their implications for Higgs and gauge boson production at the LHC.

Speaker: Giacomo Magni (VU, Nikhef)

Desy_14_12_23.pdf

18:00 The impact of LHC neutrino-ion collisions in PDF determination

Proton-proton collisions at the LHC generate a high-intensity collimated beam of neutrinos in the forward direction, up to energies of several TeV. The observation of these neutrinos by FASER$\nu$ and SND@LHC, and the proposal of a purpose-built Forward Physics Facility (FPF) for the High-Luminosity LHC (HL-LHC), motivate scientific inquiries of this hitherto unavailable particle beam. The impact of neutrino deep-inelastic scattering (DIS) measurements at the LHC on the parton distribution functions (PDFs) of protons and heavy nuclei is assessed by generating projections for FASER$\nu$ and SND@LHC at Run III, as well as for the FPF experiments FASER$\nu$2, AdvSND, and FLArE. Up to one million electron- and muon-neutrino DIS interactions within detector acceptance are expected by the end of the HL-LHC run, covering a kinematic region in $x$ and $Q^2$ that overlaps with that of the Electron-Ion Collider. Estimating the impact of these DIS projections in global (n)PDF analyses, specifically PDF4LHC21, NNPDF4.0, and EPPS21, reveals a significant reduction of PDF uncertainties, in particular for strangeness as well as the up and down valence PDFs. The LHC neutrino data is demonstrated to have the potential to improve theoretical predictions for core processes at the HL-LHC, such as Higgs production, without requiring modifications to the LHC accelerator infrastructure.

Speaker: Toni Mäkelä (NCBJ)

makela_neutrino-ion_collisions_in_PDF_determination.pdf

18:25 R&D studies and innovative technologies for the ePIC detector at EIC

ePIC is the EIC project detector designed to cope with the whole physics scope at EIC. It is the result of a more than ten year-long effort, which includes a set of preliminary detector concepts, a robust and articulated R&D program, two advanced detector architectures presented in 2021 as response to a call by the EIC hosting laboratories. More recently, a consolidation and optimization effort has been performed resulting in the present ePIC reference design, which is characterized on a set of up-to-date and innovative detector technologies resulting both from the EIC dedicated R&D and from synergies with detector developments at CERN. ePIC is pursued by a large international collaboration continuously
growing and presently consisting in 171 Institutions from USA (40 %) and all over the world.
The ePIC detector is presented with emphasis on the novel approaches and the dedicated
developments.

Speaker: Silvia Dalla Torre (IT)

ePIC_DallaTorre_EIC-LHC_synergies_DESY_20231114-15.v2.pdf

16:45 → 18:50 Synergies in physics from HERA to LHC to EIC

16:45 The ePIC experiment: detector and physics highlights

With the project to build a future Electron-Ion Collider (EIC) in the USA, equipped with a new state-of-the-art detector (ePIC), we are now preparing for the next step in precision studies of QCD.
The EIC will be the only new high-energy collider world-wide in the next twenty-thirty years. Electrons and ions, from p up to U, will collide at high luminosity on a large range of center-of-mass energies. The machine is designed to achieve a high polarization of both the lepton and the proton/light-nucleon beams. The EIC and it's ePIC detector will open a unique opportunity to address fundamental questions as the origin of the nucleon spin and will allow us for a precise 3D imaging of the partonic structure of nucleons and nuclei. Other key questions addressed by th EIC are the origin of the hadron masses and the exploration of high-density gluonic matter.
The approved project is successfully progressing at Brookhaven National Laboratory (BNL) and it includes the ePIC experiment, a general purpose detector designed to cover the whole EIC physics case.
The main characteristics of the ePIC experiment are discussed, together with highlights on the physics case and detector performance studies.

Speaker: Salvatore Fazio (University of Calabria & INFN Cosenza)

Fazio_DESY_2023_v2.pdf

17:10 PDF uncertainties and alpha_s: from HERA to EIC

Speaker: Katarzyna Wichmann (DESY)

kwichmann-synergies23.pdf

17:35 J//ψ-pair production at the LHC to study gluon TMD distributions

J/ψ-pair production at the LHC is currently the most promising tool to probe the unknown gluon transverse momentum distributions. Data from LHCb at low transverse momenta was already available and recently more data has been released.

In this presentation, I will revise previous theoretical results by discussing predictions of transverse-momentum distributions at invariant J/ψ-pair masses that were recently measured including various pair rapidities. Moreover, I explain that we implemented a novel nonperturbative Sudakov factor in the transverse momentum evolution formalism that relies on a new method to separate perturbative and nonperturbative physics in the computations. This is due to the identification of certain issues with a simple Gaussian ansatz for the nonperturbative Sudakov factor. Because the uncertainty associated to this novel Sudakov factor is found to be small, we have incorporated the PDF error as the primary source of uncertainty in our updated predictions.

I will present and discuss the normalized cross section, the azimuthal modulations that arise from linearly polarised gluons in the proton and investigate the corresponding hard scale dependencies. We note that the EIC can expand our understanding of the gluon transverse momentum distributions in the future through the study of J/ψ color octet production (Phys.Rev.D 106 (2022) 1, 014030).

Speaker: Jelle Bor

Presentation DESY 2023 Jelle Bor.pdf

18:00 Double Parton Scattering: from LHC to EIC

Abstract
In this talk we discuss how multi parton interactions (MPI), usually studied in hadron-hadron collisions, e.g. at the LHC, could be observed also at the future Electron Ion Collider (EIC). As we will show, MPI studies could represent an additional ”synergy” between LHC and EIC aimed to investigate the partonic structure of hadrons. Our first
analysis [3] has been inspired by the study of the four-jets photo-production cross-section at HERA by the ZEUS collaboration. They address the relevance of the role of MPI in the measured cross-section. Therefore, the main focus of the talk will be the calculation of the double parton scattering (DPS) contribution to the cross-section of this electromagnetic process. Our results are in qualitatively agreement with the main outcomes of the ZEUS collaboration, i.e. the DPS mechanism is not negligible. Let us remark that the main motivation of this work is the unique chance to access novel information on the proton and nucleus structure, complementary to those encoded in GPDs or TMDs. For example, from DPS initiated by photon-proton interactions, one could extract, for the first time, the mean transverse distance between two partons inside the nucleon [3]. Hopefully, it will be also possible to get some information on the so-called double parton distributions entering the cross-section of the process. These quantities encodes details on the role of parton-parton correlations. Finally, we present preliminary results of our recent activity devoted to the study double J/psi quarkonium photo-production at the EIC along the lines of Refs. [3, 4, 5, 6, 7, 8, 9]. In particular, we discuss how the quarkonium-pair photo-production probes, in different kinematical domains, can unveil new interesting information on the hadronic structure of the photon too. All these novelties could be accessible at the future EIC.
References
[1] M. Rinaldi and F. A. Ceccopieri, JHEP 1909, 097 (2019)
[2] M. Rinaldi and F. A. Ceccopieri, Phys. Rev. D 97, no. 7, 071501 (2018)
[3] F. A. Ceccopieri and M. Rinaldi, Phys. Rev. D 105 (2022) no.1, L011501
[4] J. P. Lansberg, H. S. Shao, N. Yamanaka, Y. J. Zhang and C. Noûs, Phys. Lett. B
807 (2020), 135559
[5] J. P. Lansberg, Phys. Rept. 889 (2020), 1-106 [arXiv:1903.09185 [hep-ph]].
[6] J. P. Lansberg, H. S. Shao, N. Yamanaka and Y. J. Zhang, Eur. Phys. J. C 79 (2019)
no.12, 1006 [arXiv:1906.10049 [hep-ph]].
[7] H. S. Shao and Y. J. Zhang, Phys. Rev. Lett. 117 (2016) no.6, 062001
[8] J. P. Lansberg and H. S. Shao, Nucl. Phys. B 900 (2015), 273-294
[9] J. P. Lansberg and H. S. Shao,
doi:10.1016/j.physletb.2015.10.083

Speaker: Matteo Rinaldi (Perugia University and INFN, sezione di Perugia)

Rinaldi.pdf

18:25 Investigation of the underlying event in photon-initiated processes

The underlying event in photon-initiated processes has been investigated. This has been extensively studied in proton-proton ($pp$) and proton-antiproton ($p\bar{p}$) collisions where models of the underlying event can describe data in such collisions over a wide phase-space, including the large range in energy. This leads to a single set of parameters for a given model that can be used to give a reasonable description of $pp/p\bar{p}$ data. These same parameters, as derived using the Pythia Monte Carlo model, are not able to describe data from $\gamma\gamma$, at LEP, and $\gamma p$, at HERA, collisions, where on average fewer interactions are observed. A single model and set of parameters can, however, describe simultaneously the $\gamma\gamma$ and $\gamma p$ collisions. This suggests that multi-parton interactions are different when the process is initiated by photons compared to purely hadronic collisions. Processes which are induced by photons, such as $\gamma \gamma$ events at the LHC or at future colliders such as the EIC should therefore choose the appropriate model of the underlying event.

Speaker: Matthew Wing (UCL)

Wing_14Nov2023.pdf

20:15 → 22:30 Social dinner

Friday 15 December

09:00 → 09:30 Astroparticle at Fixed Target

Speaker: Giacomo Graziani (INFN Firenze)

graziani_astroLHC.pdf

09:30 → 10:00 Impact of diffractive processes from accelerator experiments to UHECRs interactions

Speaker: Sergey Ostapchenko

desy-ostapchenko.pdf

10:00 → 10:30 UPC and diffractive physics with ions

Speaker: Ronan McNulty

upc_lhc_eic_mcnulty.pdf

10:30 → 11:00 Coffee Break

11:00 → 12:15 Exclusive production

11:00 Odderon at the EIC from exclusive production of C-even charmonia

In this contribution I would like to report on our recent computation [1,2] on exclusive C-even charmonia productions in high-energy electron-proton collisions. The C-even charmonia states serve as a probe of the odderon amplitude in the proton which is an off-forward generalized transverse momentum distribution formed by at least three gluons in a C-odd state. We are motivated by the odderon discovery of the TOTEM and D0 collaborations [3,4] in pp vs ppbar elastic collisions. Our main goal is to investigate the potential for the odderon detection at the future EIC. The computation is based on the Color Glass Condensate framework, where we numerically solve the Balitsky-Kovchegov evolution equation for coupled pomeron-odderon system. Our initial conditions are based on a microscopic quark model computation [5] that is an essential for a proper account of the so-called Donnachie-Landshoff mechanism according to which even a large-|t| scattering would not break up the proton if it involves a three-gluon exchange. Our comprehensive results cover the exclusive production of the eta_c meson [2] and the chi_cJ family (J = 0, 1, 2) [1]. While eta_c was originally suggested already long time ago [6], chi_c was not discussed so far. Due to the large branching ratio to J\Psi+gamma we argue that chi_c should be a more suitable channel for the potential odderon detection at the EIC. In our computation we pay special attention to the interference with the Primakoff process where our model computation fixes the relative phase between the two contributions. We demonstrate how the deviations from the purely Primakoff contribution can be used as a probe of the odderon amplitude in the proton at the EIC. The obtained results can be also used for the odderon searches at the LHC in the UPC mode.

[1] SB, A. Dumitru, A. Kaushik, L. Motyka, T. Stebel, in preparation

[2] SB, D. Horvatic, A. Kaushik, E. A. Vivoda, Phys. Rev. D 108 (2023) 7, 074005

[3] TOTEM collaboration, Eur. Phys. J. C 80, 91 (2020)

[4] D0 collaboration, Phys. Rev. D 86, 012009 (2012)

[5] A. Dumitru, H. Mantysaari, R. Paatelainen, Phys. Rev. D 107, L011501 (2023)

[6] J. Czyzewski, J. Kwiecinski, L. Motyka, and M. Sadzikowski, Phys. Lett. B 398, 400 (1997)

Speaker: Sanjin Benic (University of Zagreb)

benic_hamburg.pdf

11:25 Kinematic corrections in DVCS at the $1/Q^4$ power accuracy and beyond

In this talk, I will present our recent results for the kinematic corrections beyond the twist-four accuracy to the
deeply-virtual Compton scattering (DVCS) of a spin-1/2 target. Phenomenologically, such corrections are crucial for
removing the reference frame dependence when extracting the generalized parton distribution (GPD) from experimental
data. Theoretically, the kinematic corrections are also necessary for restoring the translation and gauge invariance
of the Compton amplitude. Our calculation shows explicit cancellation of the infrared divergences at the leading
order in $\alpha_$. Further numerical analysis indicates that the target mass corrections remain small, hence
validating factorizations for coherent DVCS on nuclei.

Speaker: Yao Ji (TUM)

presentation_yaoji.pdf

11:50 Anomalous dimensions for hard exclusive processes

We give an overview of recent developments in the computation of the anomalous dimension matrix of composite operators in non-forward kinematics. The elements of this matrix determine the scale dependence of non-perturbative parton distributions, such as GPDs, and hence constitute important input for phenomenological studies of exclusive processes like deeply-virtual Compton scattering. Particular emphasis will be put on a recently developed method that exploits consistency relations for the anomalous dimension matrix which follow from the renormalization structure of the operators.

Speaker: Dr Sam Van Thurenhout (Wigner RCP)

VanThurenhout_Final.pdf

11:00 → 12:15 Small x and saturation

11:00 Connecting forward LHC and the EIC: the ALICE FoCal upgrade

Forward pp and p+A measurements at the LHC probe the same QCD dipole scattering amplitudes as ep and e+A measurements at the EIC, and a comprehensive search for non-linear QCD evolution effects (“saturation”) requires extensive measurements at both facilities. The ALICE Forward Calorimeter upgrade (FoCal) provides a key element in this program. FoCal is a highly-granular forward calorimeter, which will be installed as an ALICE upgrade subsystem during LHC Long Shutdown 3 and take data during LHC Run 4. FoCal covers the pseudorapidity interval $3.2 < \eta < 5.8$, measuring direct photons, neutral mesons, vector mesons, jets, and their correlations, in hadronic and UPC pp and p+Pb collisions. These measurements will explore QCD evolution down to unprecedentedly low values of Bjorken-$x\approx10^{-6}$ at moderate $Q^2$, where non-linear QCD evolution effects are expected to be sizable. In this presentation I will discuss the FoCal detector and its projected physics performance in multiple measurement channels. The EIC, FoCal, and LHCb detector together provide “logarithmically large” coverage in x, which is essential to explore QCD evolution, and I will also discuss the question of combining such heterogeneous dataset to provide global constraints.

Speaker: Florian Jonas (UC Berkeley / LBNL)

2023-12-08-FoCalEIC_v3.pdf

11:25 Aspects of low x physics from saturation to entanglement entropy

I am going to present phenomenological predictions for cross section for forward jest production within ITMD factorization both for future FoCal calorimeter as well as for EIC. Besides that, I will discuss the recent description of hadronic entropy in inclusive as well as diffractive DIS.

Speaker: Krzysztof Kutak (Institute of Nuclear Physics Polish Academy of Sciences)

DESY2023.pdf

11:50 Coherent VM production at the EIC and LHC

The measurement of coherent diffractive Vector-Meson (VM) production sheds light on the internal structure of nuclei - probing the gluon density and saturation phenomena. However, the incoherent VM photoprduction serves as a substantial background to these measurements. In my talk, I will discuss these challenges, emphasizing the parallels as they pertain to both the LHC and EIC.

Speaker: Michael Pitt (The University of Kansas (US))

CoherentVM_MPitt.pdf

12:20 → 12:50 Event generators in DIS after the LHC experence - ep

Speaker: Daniel Reichelt (Durham University, IPPP)

ECFA_Hamburg_2023.pdf

12:50 → 13:20 Event generators in DIS after the LHC experence - eA

Speaker: Leif Lönnblad

DESY23.pdf

13:20 → 14:30 Lunch Break

14:30 → 15:00 The LHCspin project

Speaker: Marco Santimaria (INFN Frascati)

document.pdf

15:00 → 15:30 TMD shape functions

Speaker: Cristian Pisano (University of Cagliari)

synergies-cristian-pisano.pdf

15:30 → 16:00 Fracture Functions and exclusivity

Speaker: Simonetta Liuti (University of Virginia)

liuti_EIC-LHC_23.pptx

16:00 → 16:30 Coffee Break

16:30 → 17:00 ML algorithms in HEP analyses

Speaker: Cristiano Fanelli (William & Mary University)

JEENA_ML-HENP_Fanelli-upl.pdf

17:00 → 17:30 Computational needs at LHC and projections for EIC

Speaker: Enrico Bothmann (II. Physikalisches Institut, Göttingen)

enrico-bothmann.pdf

17:30 → 18:00 ep/eA collisions at the HL-LHC: synergies and complementarities between the LHeC and the LHC

The LHeC is the proposal of an energy recovery linac built at CERN to provide 30-50 GeV electrons to collide with the HL-LHC beams beyond LS5. It would study DIS in the TeV regime, with instantaneous luminosities around $10^{34}$ ($10^{33}$) in electron-proton (electron-nucleus) mode. The corresponding detector could be designed solely for the ep/eA modes or being able to study also pp/pA/AA collisions. In this talk, after introducing the new structure and activities triggered by the renewal of the CERN mandate in November 2022, we present the studies on the synergies and complementarities that an ep/eA machine at the TeV scale offers with the studies at the HL-LHC, on precision QCD and small-x physics in ep and eA, EW, Higgs, top and BSM physics.

References:
- LHeC Collaboration and FCC-he Study Group: P. Agostini et al., J. Phys. G 48 (2021) 11, 110501, e-Print: 2007.14491 [hep-ex].
- K. D. J. André et al., Eur. Phys. J. C 82 (2022) 1, 40, e-Print: 2201.02436 [hep-ex].

Speaker: Christian Schwanenberger (DESY, University of Hamburg)

LHeC_Synergies_Complementarities_HL-LHC.pdf

18:00 → 18:15 Closing remarks

Speaker: The Organizers

DESY workshop-closing.pdf