Study of newly found charmonium-like (XYZ) resonances using lattice QCD

Recently there has been tremendous interest both experimentally and theoretically to study heavy hadrons with the discovery of a large number of resonances with heavy quark content. Conventional quark models,which are very successful to study heavy hadrons, are unable to explain these states. Lattice QCD provides a unique method to study these states and can provide important information about the structures of these resonances. In this talk, I will discuss our recent lattice study of charmonium-like states with $J^{PC}=1^{++}$ in three different isospin (I=0 and 1) channels. This simulation using a large basis of $\bar cc$, two-meson and diquark antidiquark interpolating fields, with diquarks in both anti-triplet and sextet color representations, aims at a first principle study of X(3872) and Y(4140), which were observed in X(3872)->$J/\psi\rho$, $J/\psi\omega$,$D\bar{D}*$ and Y(4140)->$J/\psi\phi$. Along the way, I will briefly discuss how masses and widths of hadron resonances are extracted from lattice QCD and our results.