Speaker
Description
Abstract:
Gravitational form factors (GFFs) of the nucleon furnish a three–dimensional
map of the energy, momentum, pressure, and shear carried by QCD constituents,
with gluonic contributions playing a decisive role. Complementing lattice QCD
results, we employ a confining bottom‐up AdS/QCD model in which the bulk
dilaton background simultaneously generates linear Regge trajectories for
$2^{++}$ and $0^{++}$ glueballs, and implements the QCD trace anomaly.
Analytical expressions for the gluon $A(t)$ (energy–momentum) and
$D(t)$ (mechanical) form factors are derived, revealing a consistent picture
of the nucleon’s mass, pressure, and shear distributions.
The same holographic wave functions determine the near‐threshold
photoproduction amplitude of heavy quarkonia through Witten diagrams. We discuss the recent
extraction of gluonic GFFs by the $J/\psi\!-\!007$ collaboration at
Jefferson Lab (published in
Nature 615,813–816 (2023))
, which analyzed exclusive $J/\psi$ production on the proton
close to threshold using our holographic amplitude. The experimentally
determined tensor ($A$) and scalar ($D$) form factors exhibit excellent
agreement with lattice gluonic GFFs, reinforcing the validity of the
holographic description in the non‐perturbative regime. These developments
highlight the synergy between gauge/gravity duality, lattice computations, and
precision experiments, advancing our understanding of how gluons generate the
visible mass and mechanical structure of hadronic matter.
