The possible ${\mathrm{\Sigma }}^0$-$\mathrm{\Lambda }$ mixing in QCD sum rules

We calculate the on-shell ${\mathrm{\Sigma }}^0$-$\mathrm{\Lambda }$ mixing parameter $\theta$ with the method of QCD sum rule. Our result is $\theta (m^2_{\Sigma^0}) =(-)(0.5\pm 0.1)$MeV. The electromagnetic interaction is not included.