NUC
In the literature: open
Nuclear modification of gluons at large momentum fraction
In plain words
The EMC effect was seen for quarks, but gluons inside nuclei may also be modified. Present data barely constrain gluons carrying more than 10 percent of a nucleon's momentum.
Precise statement
Determine the ratio $g_A(x, Q^{2})/g_N(x, Q^{2})$ of the gluon distribution per nucleon in heavy nuclei to that in free nucleons for $0.1 < x < 0.6$ at $Q^{2} = 10\,\mathrm{GeV}^{2}$ with uncertainty below 10 percent. Answer: presence and size of a gluon EMC effect.
What would settle it
EIC measurements of charm production and the longitudinal structure function $F_{L}$ in electron-nucleus collisions, entered in nuclear parton-distribution fits.