We update our previous calculation of J/ψ photoproduction near threshold [Y. Hatta and D. L. Yang, Phys. Rev. D 98, 074003 (2018)PRVDAQ2470-001010.1103/PhysRevD.98.074003] by incorporating the recent developments in theory and the new experimental data from Ali et al. [the GlueX Collaboration] at Jefferson Laboratory. We then propose to study the near threshold production of φ and J/ψ in ultraperipheral pA collisions at RHIC. These processes are sensitive to the gluon condensate in the proton which is related to the proton mass via the QCD trace anomaly. Our result emphasizes the role of gluons in generating the proton mass.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)