X(3872): a - molecule with attractive diquarks

The systems are investigated by a quark model with the quark correlation, which has successfully described baryon and meson mass spectra. The results show that there can be a bound state of isospin 1, JPC=1++. This state is considered as a coupled state of the J/ψ-ρ and D-D* molecules. The size of the DD* component is smaller because the quark interaction is more attractive. We argue that this state can be X(3872).