Mass and Decay Constant of $I=1/2$ Scalar Meson In QCD Sum Rule

Abstract

We calculate the mass and decay constant of $I=1/2$ scalar mesons composed of quark-antiquark pairs based on QCD sum rule. The quauk-antiquark pairs can be $s\bar{q}$ or $q\bar{s}$ ($q=u,d$) in quark model, the quantum numbers of spin and orbital angular momentum are S=1, L=1. We obtain the mass of the ground sate in this channel is $1.410\pm 0.049$GeV. This result favors that $K_{0}^{\ast}(1430)$ is the lowest scalar state of $s\bar{q}$ or $q\bar{s}$. We also predict the first excited scalar resonance of $s\bar{q}$ is larger than 2.0 GeV.