A Laplace Sum-Rules Analysis of Heavy Pseudoscalar ($J^{PC}=0^{-+}$)   Hybrids
  We use QCD sum-rules to predict ground state masses for pseudoscalar ($J^{PC}=0^{-+}$) charmonium and bottomonium hybrids. We find that the inclusion of a six-dimensional gluon condensate contribution is needed to stabilize the analyses. For the charmonium hybrid, we find a mass of $(3.82\pm0.13)$ GeV; for the bottomonium hybrid, we find a mass of $(10.64\pm0.19)$ GeV. We comment on possible phenomenological implications concerning the Y(3940). 
D. Harnett, R. Berg, R. T. Kleiv, T. G. Steele
hep-ph