The SVZ sum rules and the heavy quark limit for $\Lambda_{Q}$

Abstract

In this work, we evaluate the accuracy of the leading order results in Shifman-Vainshtein-Zakharov (SVZ) sum rules and the leading power results in the heavy quark limit for the mass of $\Lambda_{Q}$. Up to dim-5 condensate contributions are considered. By comparing with the experimental results, we find that the leading order results in SVZ sum rules can reach about 5\% accuracy both for $\Lambda_{b}$ and $\Lambda_{c}$, and it seems that better results can be obtained from the sum rules of the heavy quark limit both for $\Lambda_{b}$ and $\Lambda_{c}$. We re-check that the SVZ sum rules in the heavy quark limit coincide with the HQET sum rules. As a byproduct, we also have an exploratory discussion on the $ud$ diquark in $\Lambda_{Q}$.