2025 EIC-France Workshop: Physics Highlights and Perspectives

TL;DR

This paper summarizes the theoretical discussions and strategic priorities of the French hadron-physics community for the upcoming Electron-Ion Collider, highlighting key early measurements and future research directions in QCD physics.

Contribution

It provides a comprehensive overview of recent theoretical developments, experimental plans, and long-term physics opportunities related to the EIC, emphasizing French contributions.

Findings

Inclusive diffraction and quarkonium production are ideal for early EIC measurements.

These channels are sensitive to gluon saturation and small-x physics.

Long-term opportunities include studying the pion structure and exclusive three-body states.

Abstract

This document presents a synthesis of the theory contributions and discussions from the 2nd EIC-France Workshop, held at IJCLab (Orsay) on 1-3 December 2025. The workshop brought together members of the French hadron-physics community to review recent theoretical developments relevant to the future Electron-Ion Collider (EIC) and to coordinate national efforts in preparation for its early physics program. The report first summarizes the collider's initial running conditions and luminosity performance, as outlined in the EIC Early Science Matrix. It then provides concise overviews of the theoretical presentations on inclusive, semi-inclusive, exclusive, heavy-flavor, and small-x physics. Based on these discussions, two measurements emerged as especially well suited for early EIC operation and strongly aligned with areas of established French expertise: inclusive diffraction and inclusive quarkonium production. These channels offer clean signatures, robust theoretical interpretability, and direct sensitivity to fundamental QCD phenomena such as gluon saturation, heavy-quark dynamics, and the small-x structure of hadrons and nuclei. In addition, the workshop identified longer-term physics opportunities that will benefit from the full capabilities of the EIC after its ramp-up phase. These include accessing the three-dimensional structure of the pion through the Sullivan process and a broader program of exclusive three-body final states, both of which represent high-impact avenues for exploring hadronic structure and non-perturbative QCD. Together, the elements summarized in this report provide a coherent overview of the strategic priorities and scientific ambitions shaping the French community's contribution to the EIC physics program.