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The trace of the stress tensor characterizes the transformation of a theoryunder rescaling. In quantum chromodynamics (QCD), this trace containscontributions from the bare masses of the quarks and also from a purely quantumeffect, called the QCD trace anomaly. It affects all masses in the theory. Wepresent an estimation of the QCD trace anomaly from the near-threshold J/${\rm\Psi}$ photo-production data of the GlueX experiment, at JLab. We apply avector meson dominance model to describe the photo-production of J/${\rm \Psi}$and a running strong coupling which includes the nonperturbative effects in thelow $\mu^2$ region. Despite the large uncertainty, we find that theexperimental data favors a small value of the trace anomaly parameter$b=0.07\pm 0.17$. We report the resulting proton mass decompositions at$\mu^2=0.41$ GeV$^2$ and $\mu^2=4$ GeV$^2$.

The Origin of Proton Mass from J/${\rm \Psi}$ Photo-production Data