Lowest vector tetraquark states: Y(4260 / 4220) or $$Z_c(4100)$$ Zc(4100)

Abstract

Abstract In this article, we take the Y(4260 / 4220) as the vector tetraquark state with $$J^{PC}=1^{--}$$ JPC=1-- , and construct the $$C\gamma _5\otimes {\mathop {\partial }\limits ^{\leftrightarrow }}_\mu \otimes \gamma _5C$$ Cγ5⊗∂↔μ⊗γ5C type diquark-antidiquark current to study its mass and pole residue with the QCD sum rules in details by taking into account the vacuum condensates up to dimension 10 in a consistent way. The predicted mass $$M_{Y}=4.24\pm 0.10\,\mathrm {GeV}$$ MY=4.24±0.10GeV is in excellent agreement with experimental data and supports assigning the Y(4260 / 4220) to be the $$C\gamma _5\otimes {\mathop {\partial }\limits ^{\leftrightarrow }}_\mu \otimes \gamma _5C$$ Cγ5⊗∂↔μ⊗γ5C type vector tetraquark state, and disfavors assigning the $$Z_c(4100)$$ Zc(4100) to be the $$C\gamma _5\otimes {\mathop {\partial }\limits ^{\leftrightarrow }}_\mu \otimes \gamma _5C$$ Cγ5⊗∂↔μ⊗γ5C type vector tetraquark state. It is the first time that the QCD sum rules have reproduced the mass of the Y(4260 / 4220) as a vector tetraquark state.