QCD Sum Rules Calculation of Heavy $\mathrm{\Lambda }$ Semileptonic Decay

We set up sum rules for heavy lambda decays in a full QCD calculation which in the heavy quark mass limit incorporates the symmetries of heavy quark effective theory. For the semileptonic ${\text{La}}_c$ decay we obtain a reasonable agreement with experiment. For the ${\text{La}}_b$ semileptonic decay we find at the zero recoil point a violation of the heavy quark symmetry of about 20%.