In this work,we generate gauge configurations with N_(f)=2 dynamical charm quarks on anisotropic lattices.The mass shift of 1S and 1P charmonia due to the charm quark annihilation effect can be investigated directly i...In this work,we generate gauge configurations with N_(f)=2 dynamical charm quarks on anisotropic lattices.The mass shift of 1S and 1P charmonia due to the charm quark annihilation effect can be investigated directly in a manner of unitary theory.The distillation method is adopted to treat the charm quark annihilation diagrams at a very precise level.For 1S charmonia,the charm quark annihilation effect barely changes the J/ψmass,but lifts theη_(c) mass by approximately 3-4 MeV.For 1P charmonia,this effect results in positive mass shifts of approximately 1 MeV for χ_(c)1 and h_(c),but decreases the χ_(c)2 mass by approximately 3 MeV.We did not obtain a reliable result for the mass shift of χ_(c)0.In addition,we observed that the spin averaged mass of the spin-triplet 1P charmonia is in good agreement with h_(c),as expected by the non-relativistic quark model and measured by experiments.展开更多
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030302)the National Key Research and Development Program of China(2020YFA0406400)the National Natural Science Foundation of China(NSFC)(11935017,11775229,12075253,12070131001)(CRC 110 by DFG and NNSFC)。
文摘In this work,we generate gauge configurations with N_(f)=2 dynamical charm quarks on anisotropic lattices.The mass shift of 1S and 1P charmonia due to the charm quark annihilation effect can be investigated directly in a manner of unitary theory.The distillation method is adopted to treat the charm quark annihilation diagrams at a very precise level.For 1S charmonia,the charm quark annihilation effect barely changes the J/ψmass,but lifts theη_(c) mass by approximately 3-4 MeV.For 1P charmonia,this effect results in positive mass shifts of approximately 1 MeV for χ_(c)1 and h_(c),but decreases the χ_(c)2 mass by approximately 3 MeV.We did not obtain a reliable result for the mass shift of χ_(c)0.In addition,we observed that the spin averaged mass of the spin-triplet 1P charmonia is in good agreement with h_(c),as expected by the non-relativistic quark model and measured by experiments.
