Exotic states from lattice QCD (ended after funding period 2)

Y. Chen (IHEP) / C. Urbach (UB)

In this project, we shall investigate the nature of the scalar mesons and charmonium-like XYZ particles using lattice QCD with N_f = 2 + 1 + 1 dynamical quark flavors – based on configurations generated by the European Twisted Mass Collaboration (ETMC). In the first funding period of this CRC, we have made great effort to generate the perambulators, which encode the all-to-all quark propagators, for each quark flavor and on each gauge ensemble by the use of the sophisticated distillation method. With these perambulators, quark annihilation diagrams can be elegantly dealt with. In the second funding period, we shall start with the lightest scalar mesons as well as the X(3872) states and then study the production rates of ordinary mesons in the radiative decays of J/ψ to identify the decay productions as either conventional mesons or exotic mesons