He, J (reprint author), Chinese Acad Sci, Inst Modern Phys, Div Theoret Phys, Lanzhou 730000, Peoples R China.
In this paper it is proposed that the charged charmonium-like state Z(c)(3900) is a resonance above threshold from the D (D) over bar* interaction. The D (D) over bar* interaction is described by the one-bosn-exchange model with light meson exchanges plus a short-range J/psi exchange. The scattering amplitude is calculated within a Bethe-Saltpeter equation approach and the poles near the D (D) over bar* threshold are searched. In isoscalar sector, two poles found under the D (D) over bar* threshold-i.e., bound states-have quantum numbers I-G(J(PC)) = 0(-)(1(+-)) and 0(+)(1(++)). The latter can be related to the X(3872). In the isovector sector, a bound state with I-G(J(P)) = 1(+)(1(+)) is found with a large cut off about 3 GeV. If a cut off about 2 GeV is adopted with which a pole carrying quantum number of the X(3872) is produced at energy about 3871 MeV, the pole for the bound state with 1(+)(1(+)) runs across the threshold to second Rienman sheet and becomes a resonance above the D (D) over bar* threshold, which can be identified with the Z(c)(3900). With such cut off, the D (D) over bar* invariant mass spectrum is also investigated and the experimental results by BESIII can be reproduced
Major State Basic Research Development Program in China [2014CB845405]
; National Natural Science Foundation of China [11275235, 11035006]
; Chinese Academy of Sciences (the Knowledge Innovation Project) [KJCX2-EW-N01]