Spectator Effects in Heavy Quark Effective Theory at O(1/m_Q^3)
  We complete the one loop renormalization of the HQET lagrangian at O(1/m_Q^3) including four fermion operators with two heavy and two light quark fields in the operator basis. It is shown that as a consequence the short distance coefficients of the operators bilinear in the heavy quark field receive nontrivial corrections. 
Christopher Balzereit