Abstract
AbstractThe trace of the stress tensor characterizes the transformation of a theory under rescaling. In quantum chromodynamics (QCD), this trace contains contributions from the bare masses of the quarks and also from a purely quantum effect, called the QCD trace anomaly. It affects all masses in the theory. We present an estimation of the QCD trace anomaly from the near-threshold $$\hbox {J}/{\Psi }$$
J
/
Ψ
photo-production data of the GlueX experiment, at JLab. We apply a vector meson dominance model to describe the photo-production of $$\hbox {J}/{\Psi }$$
J
/
Ψ
and a running strong coupling which includes the nonperturbative effects in the low $$\mu ^2$$
μ
2
region. Despite the large uncertainty, we find that the experimental data favors a small value of the trace anomaly parameter $$b=0.07\pm 0.17$$
b
=
0.07
±
0.17
. We report the resulting proton mass decompositions at $$\mu ^2=0.41\hbox { GeV}^2$$
μ
2
=
0.41
GeV
2
and $$\mu ^2=4\hbox { GeV}^2$$
μ
2
=
4
GeV
2
.
Funder
CAS Key Research Program of Frontier Sciences
National Natural Science Foundation of China
Strategic Priority Research Program of Chinese Academy of Sciences
Publisher
Springer Science and Business Media LLC
Subject
Physics and Astronomy (miscellaneous),Engineering (miscellaneous)
Cited by
43 articles.
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