Improved Determination of the Mass of the $1^{-+}$ Light Hybrid Meson From QCD Sum Rules

Abstract

We calculate the next-to-leading order (NLO) $α_s$-corrections to the contributions of the condensates $<αG^2>$ and $<\bar qq>^2$ in the current-current correlator of the hybrid current $g\barq(x)γ_νiF_{μν}^aT^aq(x)$ using the external field method in Feynman gauge. After incorporating these NLO contributions into the Laplace sum-rules, the mass of the $J^{PC}$=$1^{-+}$ light hybrid meson is recalculated using the QCD sum rule approach. We find that the sum rules exhibit enhanced stability when the NLO $α_s$-corrections are included in the sum rule analysis, resulting in a $1^{-+}$ light hybrid meson mass of approximately 1.6 GeV.