IGJPC=1-1-+ tetraquark states

We study the tetraquark states with I(G)J(PC) = 1(-)1(-+) in the QCD sum rule. After exhausting all possible flavor structures, we analyze both the Shifman-Vainshtein-Zakharov (SVZ) and finite energy sum rules. Both approaches lead to a mass around 1.6 GeV for the state with the quark contents qq (q) over bar(q) over bar, and around 2.0 GeV for the state with the quark contents qs (q) over bar(s) over tilde. The flavor structure ((3) over bar circle times (6) over bar) circle plus (6 circle times 3) is preferred. Our analysis strongly indicates that both pi(1)(1600) and pi(1)(2015) are also compatible with the exotic tetraquark interpretation, which are sometimes labeled as candidates of the 1(-+) hybrid mesons. Moreover one of their dominant decay modes is a pair of axial- vector and pseudoscalar mesons such as b(1)(1235)pi, which is sometimes considered as the characteristic decay mode of the hybrid mesons.