Indications of the possible observation of the lowest-lying 1^{-+} QCD state

Abstract

We discuss properties of 1^{-+} exotic mesons within the framework of the QCD field-theoretic approach. We estimate the mass of the lowest-lying 1^{-+} exotic meson using renormalization-improved QCD sum rules, and find that the mass lies around $1.26\pm 0.15$ GeV, in good agreement with the $\pi_1(1400)$ data. This state should be expected in QCD. We find that the mass for the lowest-lying strange 1^{-+} meson is $1.31\pm 0.19$ GeV. Our result hints that the K^*(1410) may be the lowest-lying 1^{-+} nonet state.