Strong $Z_c^{+}(3900)\rightarrow J/\psi \pi^{+}; \eta_{c} \rho^{+}$ decays in QCD

Understand

The widths of the strong decays $Z_c^{+}(3900)\to J/\psi \pi^{+}$ and $Z_c^{+}(3900)\to \eta_{c} \rho^{+}$ are calculated.

• To this end, the mass and decay constant of the exotic $Z_c^{+}(3900)$ state are computed by means of a two-point sum rule.
• The obtained results are then used to calculate the strong couplings $g_{Z_{c}J/\psi \pi }$ and $g_{Z_{c}\eta_{c} \rho }$ employing QCD sum rules on the light-cone supplied by a technique of the soft-meson approximation.
• We compare our predictions on the mass and decay widths with available experimental data and other theoretical results.