New predictions on the mass of the $1^{-+}$ light hybrid meson from QCD sum rules

Abstract

We calculate the coefficients of the dimension-8 quark and gluon condensates in the current-current correlator of $1^{-+}$ light hybrid current $g\bar{q}(x){\gamma }_{\nu }i{G}_{\mu \nu }(x)q(x)$. With inclusion of these higher-power corrections and updating the input parameters, we re-analyze the mass of the $1^{-+}$ light hybrid meson from Monte-Carlo based QCD sum rules. Considering the possible violation of factorization of higher dimensional condensates and variation of $⟨g^3{G}^3⟩$, we obtain a conservative mass range 1.72--2.60\,GeV, which favors ${\pi }_1(2015)$ as a better hybrid candidate compared with ${\pi }_1(1600)$ and ${\pi }_1(1400)$.

12pages, 2 figures, the version appearing in JHEP