Evidence for X(3872) from DD* Scattering on the Lattice

A candidate for the charmonium(like) state X(3872) is found 11 +/- 7 MeV below the D (D) over bar* threshold using dynamical N-f = 2 lattice simulation with J(PC) = 1(++) and I = 0. This is the first lattice simulation that establishes a candidate for X(3872) in addition to the nearby scattering states D (D) over bar* and J/psi omega which inevitably have to be present in dynamical QCD. We extract large and negative D (D) over bar* scattering length a(0)(DD)* = -1.7 +/- 0.4 fm and the effective range r(0)(DD)* = 0.5 +/- 0.1 fm, but their reliable determination will have to wait for a simulation on a larger volume. In I = 1 channel, only the D (D) over bar* and J/psi rho scattering states are found and no candidate for X(3872). This is in agreement with the interpretation that X(3872) is dominantly I = 0, while its small I = 1 component arises solely from the isospin breaking and is therefore absent in our simulation with m(u) = m(d).