Workshop on 𝛾𝛾 physics at electron-hadron colliders

Friday 28 Feb 2025, 08:00 → 19:00 Europe/Warsaw

D-10 D-czarna (AGH University of Kraków)

Laurent Forthomme (AGH University of Krakow (PL)), Hamzeh Khanpour (AGH University of Science and Technology), Krzysztof Piotrzkowski (AGH University (Kraków, PL))

Modelling photon interactions from the EIC to the LHeC. Including spin physics and nuclear effects.

Participation by invitation.

 

workshop_poster.png

09:00 Welcoming

1 Workshop introduction

Speakers: Hamzeh Khanpour (AGH University of Science and Technology), Krzysztof Piotrzkowski (AGH University (Kraków, PL)), Laurent Forthomme (AGH University of Krakow (PL))

AGH_Workshop_Welcome.pdf

2 Exploring High Energy Photon-Photon Interactions at the LHeC

The future Large Hadron-Electron Collider (LHeC) provides a unique platform to explore high-energy photon-photon ($\gamma \gamma$) interactions in electron-proton collisions. This talk focuses on the exclusive production of lepton pairs and the potential to probe supersymmetric particles, such as higgsinos, through photon-induced processes. Utilizing the Equivalent Photon Approximation (EPA), we investigate the kinematic properties and cross-sections of such interactions. Additionally, we compare our calculations based on EPA with predictions from various event generators, including cepgen/Lpair, and GRAPE, demonstrating excellent agreement. The high luminosity and clean environment of the LHeC make it an ideal laboratory for testing photon-induced processes, providing valuable insights into electroweak interactions and possible extensions of the SM.

Speaker: Hamzeh Khanpour (AGH University of Science and Technology)

Hamzeh_Khanpour_yy_at_AGH.pdf

3 Production of exclusive dijets at electron-proton colliders

Speaker: Antoni Szczurek

szczurek_LHeC2025_dijets.pdf

4 Photon transition form factors of C-even quarkonia for virtual photons

Speaker: Wolfgang Schaefer

WS_gamgam_AGH.pdf

10:30 Coffee break

5 Virtual Compton scattering processes in upcoming experiments

In my talk, I will describe recent progress in the study of a family of virtual Compton scattering (VCS) processes within the framework of generalized parton distributions (GPDs). This includes deeply virtual Compton scattering (DVCS), timelike Compton scattering (TCS), and double deeply virtual Compton scattering (DDVCS). I will also focus on the measurability of these processes in upcoming JLab and EIC experiments. In particular, I will present preliminary impact studies for DVCS at EIC.

Speaker: Paweł Sznajder (National Centre for Nuclear Research)

sznajder_krakow_0225.pdf

6 𝛾𝛾 → µ+µ-, 𝜏+𝜏- at EIC

The two-photon exclusive production of lepton pairs at the Electron–Ion Collider will open interesting research directions thanks to a very high luminosity and clean experimental conditions. A survey of the scientific potential of such studies is reported. In particular, we consider unique measurements of the proton elastic electromagnetic form-factors and a possibility of studying the anomalous electromagnetic dipole moments of tau leptons.

Speaker: Krzysztof Piotrzkowski (AGH University (Kraków, PL))

dileptons_KP.pdf

7 Two-photon physics with the CepGen event generator and 𝛾𝛾 → W+W-/ZZ at LHC and LHeC

CepGen is a matrix element level Monte Carlo generator intended for the simulation of central exclusive processes (and in particular $\gamma\gamma$) at LHC. In the recent years, numerous extensions allowed it to simulate an even broader range, e.g. diffraction and UPC interactions.
In this talk, the generator will be presented along its modular extensions capability, allowing e.g. the definition of new processes, and incoming partons fluxes modellings, or interfacing to existing libraries.

Speaker: Laurent Forthomme (AGH University of Krakow (PL))

gg-cepgen.pdf

12:00 Lunch break

8 Topical discussion

• Precise simulation of Bethe-Heitler two-photon production of lepton pairs at polarised EIC
• Tau-tau production & decay at EIC
• Nuclear effects in gamma-gamma to lepton pairs at eA@EIC
• Tau-tau final state analysis at LHeC
• Two-photon production of W, or Z pairs at LHeC (incl. 2-to-6 simulation)
• Photoproduction of t-tbar at LHeC
• Event generators developments

AGH_Workshop_Discussion_Session.pdf

Future of CERN.pdf