The I^G J^{PC}=1^- 1^{-+} Tetraquark States

Abstract

We study the tetraquark states with I^G J^{PC}=1^- 1^{-+} in the QCD sum rule. After exhausting all possible flavor structures, we analyses both the SVZ and finite energy sum rules. Both approaches lead to a mass around 1.6 GeV for the state with the quark contents q q q_bar q_bar, and around 2.0 GeV for the state with the quark contents q s q_bar s_bar. The flavor structure 3_bar * 6_bar + 6 * 3 is preferred. Our analysis strongly indicates that both pi1(1600) and pi1(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 b1(1235) pi, which is sometimes considered as the characteristic decay mode of the hybrid mesons.

18 pages, 14 figures, revised version to appear in Phys. Rev. D