The decay width of the Z_c(3900) as an axialvector tetraquark state in solid quark\u2013hadron duality

Abstract

In this article, we tentatively assign the Z_c^pm (3900) to be the diquark–antidiquark type axialvector tetraquark state, study the hadronic coupling constants G_{Z_cJ/psi pi }, G_{Z_ceta _crho }, G_{Z_cD bar{D}^{*}} with the QCD sum rules in details. We take into account both the connected and disconnected Feynman diagrams in carrying out the operator product expansion, as the connected Feynman diagrams alone cannot do the work. Special attentions are paid to matching the hadron side of the correlation functions with the QCD side of the correlation functions to obtain solid duality, the routine can be applied to study other hadronic couplings directly. We study the two-body strong decays Z_c^+(3900)rightarrow J/psi pi ^+, eta _crho ^+, D^+ bar{D}^{*0}, bar{D}^0 D^{*+} and obtain the total width of the Z_c^pm (3900). The numerical results support assigning the Z_c^pm (3900) to be the diquark–antidiquark type axialvector tetraquark state, and assigning the Z_c^pm (3885) to be the meson–meson type axialvector molecular state.