Computing non-factorizable pQCD corrections to hadronic B^0 - \bar B^0   mixing matrix element within sum rules technique for three point Green   functions
  In this talk I report on the results of a recent calculation of the \alpha_s corrections to a three-point correlation function at the three-loop level in QCD perturbation theory, which allows one to extract the matrix element of B^0 -\bar B^0 mixing with next-to-leading order accuracy. The evaluation of mixing parameter at NLO allows for a consistent analysis of B^0 -\bar B^0 mixing since the coefficient functions of the effective Hamiltonian for this process are known with the necessary accuracy. 
A. A. Pivovarov