Hadron masses can be decomposed as a sum of components which are defined through hadronic matrix elements of QCD operators. The components consist of the quark mass term, the quark energy term, the glue energy term and the trace anomaly term. We calculate these components of mesons with lattice QCD for the first time. The calculation is carried out with overlap fermion on 2+1 flavor domain-wall fermion gauge configurations. We confirm that ∼ 50% of the light pion mass comes from the quark mass and ∼ 10% comes from the quark energy, whereas, the contributions are found to be the other way around for the ρ mass. The combined glue components contribute ∼ 40-50% for both mesons. It is interesting to observe that the quark mass contribution to the mass of the vector meson is almost linear in quark mass over a large quark mass region below the charm quark mass. For heavy mesons, the quark mass term dominates the masses, while the contribution from the glue components is about 400 ∼ 500 MeV for the heavy pseudoscalar and vector mesons. The charmonium hyperfine splitting is found to be dominated by the quark energy term which is consistent with the quark potential model.
|Proceedings of Science
|Published - 2014
|32nd International Symposium on Lattice Field Theory, LATTICE 2014 - New York, United States
Duration: Jun 23 2014 → Jun 28 2014
Bibliographical noteFunding Information:
∗This work is supported in part by the National Science Foundation of China (NSFC) under Grants No. 11075167, No. 11105153, and No. 11335001, and also by the U.S. DOE Grant No. DE-FG05-84ER40154. Y.C. and Z.L. also acknowledge the support of NSFC and DFG through funds provided to the Sino-German CRC 110 “Symmetries and the Emergence of Structure in QCD". †Speaker.
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