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QCD trace anomaly and the proton mass problem

Date:
Speaker(s) / Presenter(s):
Yoshitaka Hatta
The trace anomaly of QCD is fundamentally important as it imparts mass to hadrons and nuclei, hence to the visible universe.
In this talk, I will introduce two recent developments regarding the anomaly. In the first part, I discuss the decomposition of the trace anomaly into the quark and gluon parts. This is a well-defined field theoretical problem that can be addressed in perturbation theory. In the second part, I will explain how to measure the gluon condensate $\lange P|F^{\mu\nu}F_{\mu\nu}|P\rangle$, which constitutes the major part of the trace anomaly, in near-threshold $J/\psi$ production in electron-proton scattering. After giving a review of the existing theoretical approaches and the experimental situation, I will explain our new approaches to both photo-production and lepto-production.
 
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