Fate of the Tetraquark Candidate Zc(3900) from Lattice QCD

The possible exotic meson Z(c)(3900), found in e(+)e(-) reactions, is studied by the method of coupled-channel scattering in lattice QCD. The interactions among pi J/psi, rho eta(c), and (D) over barD* channels are derived from (2 + 1)-flavor QCD simulations at m(pi) = 410-700 MeV. The interactions are dominated by the off-diagonal pi J/psi-(D) over barD* and rho eta(c)-(D) over barD* couplings, which indicates that the Z(c)(3900) is not a usual resonance but a threshold cusp. Semiphenomenological analyses with the coupled-channel interaction are also presented to confirm this conclusion.