We investigate whether the final state interaction (FSI) effect plays a
significant role in the large hidden charm decay width of X(3872) and Y(3940)
using a model. Our numerical result suggests (1) the FSI contribution to
X(3872)→J/ψρ is tiny; (2) Γ[Y(3940)→DDˉ∗+h.c.→J/ψω] from FSI is around several keV, far
less than Belle's experimental value 7 MeV.Comment: 5 pages, 3 figures, 1 table. Version to appear in Physics Letters