Heavy Baryons:. a Combined Large Nc and Heavy Quark Expansion for Electroweak Currents

The combined large N_c and heavy quark limit for baryons containing a single heavy quark is discussed. The combined large N_c and heavy quark expansion of the heavy quark bilinear operators is obtained. In this expansion, the corrections proportional to m_N/m_Q are summed to all orders. In particular, the expansion can be used to determine semileptonic form factors of heavy baryons in the combined limit.