A first study of the semi-leptonic decay of the $\Lambda_b$ baryon
  We present the preliminary results of the first Lattice study of the baryonic Isgur and Wise function obtained from the matrix element of the weak current between $\Lambda$-baryon external states. Its dependence on the heavy and light quark masses is studied. Some result on the semi-leptonic decay $\Lambda_b\to\Lambda_c +l\nu$ are given. 
Nicoletta Stella (UKQCD Collaboration)