$Z_c^+(3900)$ decay width in QCD sum rules

Abstract

We identify the recently observed charmonium-like structure $Z_c^\pm(3900)$ as the charged partner of the X(3872) state. Using standard techniques of QCD sum rules, we evaluate the three-point function and extract the coupling constants of the $Z_c \, J/ψ\, π^+$ and $Z_c \, η_c \, ρ^+$ vertices and the corresponding decay widths in these channels. The good agreement with the experimental data gives support to the tetraquark picture of this state.

new section and two more figures added