Improved analysis for the baryon masses to order ΛQCD/mQ from QCD sum rules -: art. no. 094036

We use the QCD sum rule approach to calculate the masses of the Lambda(Q) and Sigma(Q) baryons to Lambda(QCD)/m(Q) order within the framework of heavy quark effective theory. We compare the direct approach and the covariant approach to this problem. Two forms of current have been adopted in our calculation and their effects on the results are discussed. Numerical results obtained in both the direct and covariant approaches are presented. The splitting between spin 1/2 and 3/2 doublets derived from our calculation is Sigma(Q)(*2)-Sigma(Q)(2)similar or equal to0.35+/-0.03 GeV2, which is in good agreement with experiment.