Choice of heavy baryon currents in QCD sum rules

Abstract

In this paper we investigate the effects due to the mixing of two interpolating currents for ground-state baryons within the framework of heavy quark effective theory using the QCD sum rule approach. Both two-point and three-point sum rules, and thus the mass, coupling constant, and Isgur-Wise function sum rules are considered. It is interesting to contrast those results with each other. Based on the Isgur-Wise functions obtained in this paper, we also analyze the effects of current mixing to $\ensuremath{\Lambda}$ type and and $\ensuremath{\Sigma}$ type semileptonic decays ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}\mathcal{l}\overline{\ensuremath{\nu}},{\ensuremath{\Sigma}}_{b}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{c}\mathcal{l}\overline{\ensuremath{\nu}},$ and ${\ensuremath{\Sigma}}_{b}\ensuremath{\rightarrow}{\ensuremath{\Sigma}}_{c}^{*}\mathcal{l}\overline{\ensuremath{\nu}}.$ Decay widths corresponding to various mixing parameters are obtained and can be compared to the experimental data.