Z_c(3900)/Z_c(3885) as a virtual state from pi J/psi -bar{D}^*D interaction

Abstract

In this work, we study the {pi !}J{!/}psi and bar{D}^*D invariant mass spectra of the Y(4260) decay to find out the origin of the Z_c(3900) and Z_c(3885) structures. The {pi !}J{!/}psi -bar{D}^{*}D interaction is studied in a coupled-channel quasipotential Bethe–Saltpeter equation approach, and embedded to the Y(4260) decay process to reproduce both {pi ^{-}!}J{!/}psi and D^{*-}D^0 invariant mass spectra observed at BESIII simultaneously. It is found out that a virtual state at energy about 3870 MeV is produced from the interaction when both invariant mass spectra are comparable with the experiment. The results support that both Z_c(3900) and Z_c(3885) have the same origin, that is, a virtual state from {pi !}J{!/}psi -bar{D}^*{D} interaction, in which the bar{D}^*{D} interaction is more important and the coupling between bar{D}^*{D} and {pi !}J{!/}psi channels plays a minor role.