2025/10/21 by Cyrille Marquet, Yu Shi, Marquet, Cyrille +3 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2510.18949
openalex publication_date 2025/10/21 · openalex created_date 2025/10/24 · openalex updated_date 2026/08/01
We develop a unified resummation framework for heavy-meson pair photoproduction that treats soft-gluon radiation in a massive scheme for |\boldsymbol q| \lesssim mQ and is consistent with the massless limit mQ ≪ |\boldsymbol q|, where \boldsymbol q denotes the transverse momentum of the pair and mQ the quark mass. This framework describes the full correlation regime |\boldsymbol q| ≪ |\boldsymbol P|, with \boldsymbol P the pair's relative transverse momentum. Next, within the Color Glass Condensate framework, we quantify the impact of soft gluon radiation on two important phenomenological observables, namely, the azimuthal Δϕ correlation and the harmonic asymmetries ⟨ cos(2nϕqP)⟩. Our results show that the resummation provides an excellent description of the H1 Δϕ data. We then find that the angular-asymmetry harmonics are sizable and their ratios in γA to γp collisions are highly sensitive to gluon saturation. We further find a clear mass hierarchy in both observables, indicating that heavy-quark masses suppress soft radiation and thereby enhance genuine small-x saturation signals. Our work demonstrates that heavy-quark pair photoproduction provides a quantitative probe of gluon saturation, directly measurable in forthcoming EIC and UPC measurements. Finally, the unified resummation is readily extendable to other processes involving massive particles and jets in both eA and pA collisions.