First Measurement of Near- and Sub-Threshold $J/\psi$ Photoproduction
off Nuclei
First Measurement of Near- and Sub-Threshold $J/\psi$ Photoproduction
off Nuclei
We report on the first measurement of $J/\psi$ photoproduction from nuclei in the photon energy range of $7$ to $10.8$ GeV, extending above and below the photoproduction threshold in the free proton of $\sim8.2$ GeV. The experiment used a tagged photon beam incident on deuterium, helium, and carbon, and the …