Near threshold $J/\psi$ and $\Upsilon$ photo-production at JLab and RHIC

Understand

We update our previous calculation of $J/\psi$ photo-production near threshold \cite{Hatta:2018ina} by incorporating the recent developments in theory and the new experimental data from the GlueX collaboration at Jefferson Lab \cite{Ali:2019lzf}.

• We then propose to study the near threshold production of $\Upsilon$ and $J/\psi$ in ultraperipheral $pA$ collisions at RHIC.
• These processes are sensitive to the gluon condensate in the proton which is related to the QCD trace anomaly.
• Our result emphasizes the role of gluons as the origin of the proton mass.