Near-Threshold J/ψ→μ+μ− Photoproduction and the Gluonic Gravitational Form Factors of the Proton
This paper reports the measurement of near-threshold J/ψ→μ+μ− photoproduction cross sections from the J/ψ-007 experiment at Jefferson Lab, which, when combined with electron decay data and analyzed via Holographic QCD, yields precise constraints on the proton's gluonic gravitational form factor Cg(t) that agree with lattice QCD calculations and support a spatial picture of gluon dominance at larger radii with confining inward pressure.
007 Collaboration, S. Joosten, Z. -E. Meziani, S. Prasad, J. Swartz, B. Duran, M. K. Jones, H. Klest, M. Paolone, C. Peng, W. Armstrong, H. Atac, E. Chudakov, H. Bhatt, D. Bhetuwal, M. Boer, A. Camson (…)2026-02-26⚛️ nucl-ex