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

TL;DR

This paper refines the QCD sum rule calculations for the mass of the $1^{-+}$ light hybrid meson by including higher-dimensional condensates and updated parameters, suggesting $ ext{pi}_1(2015)$ as a promising hybrid candidate.

Contribution

It introduces the calculation of dimension-8 condensates and updates analysis methods, providing a more comprehensive mass estimate for the light hybrid meson.

Findings

Mass range 1.72--2.60 GeV for the hybrid meson.

Supports $ ext{pi}_1(2015)$ as a better hybrid candidate.

Highlights the impact of higher-dimensional condensates on mass predictions.

Abstract

We calculate the coefficients of the dimension-8 quark and gluon condensates in the current-current correlator of $1^{-+}$ light hybrid current $g\bar{q}(x)\gamma_{\nu}iG_{\mu\nu}(x)q{(x)}$. 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 $\langle g^3G^3\rangle$, 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 $\pi_{1}(1400)$.