The possible $\Sigma^0$-$\Lambda$ mixing in QCD sum rules
  We calculate the on-shell $\Sigma^0$-$\Lambda$ 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. 
Shi-Lin Zhu(1,2), W.-Y.P.Hwang(3) and Ze-sen Yang(1), ((1) Physics   department, Peking Uinversity, (2) Institute of Theoret...