Lattice studies of charmonia and exotics

Abstract

The lattice QCD simulations of charmonia and exotic charmonium-like states are reviewed. I report on the first exploratory simulation of charmonium resonances above open charm threshold which takes into account the strong decay. The puzzles related to the first-excited scalar charmonia are discussed. Evidence for X(3872) is presented along with investigation of its Fock components. The $Z_c^+(3900)$ seems to emerge from the HALQCD approach as a result of the coupled channel effect $J/\psi \pi -D\bar D^*$. The indication for the pentaquark bound state $\eta_c N$ is presented.