mass of $1^{-+}$ fourqurk-hyrbird mixed states

We calculate the mass of $J^{PC}=1^{-+}$ light exotic mesons by QCD sum rules, the mass are extracted from fourquark-hybrid correlation functions. We construct several $1^{-+}$ fourquark molecule currents and hybrid currents, and get one mass around $1.2\text{-}1.4\text{GeV}$ and another one around $1.45\text{-}1.67\text{GeV}$. They can be identified as $\pi_1(1400)$ and $\pi_1(1600)$. We also find fourquark current commonly mix with hybrid-like currents under renormalization. The two $1^{-+}$ states are mixed states of fourquark and hybrid.