title: B0-B(-)0 mixing beyond factorization in QCD sum rules.
abstract: We present a calculation of the B0-B(-)0 mixing matrix element in the framework of QCD sum rules for three-point functions. We compute alpha(s) corrections to a three-point function at the three-loop level in QCD perturbation theory, which allows one to extract the matrix element with next-to-leading order (NLO) accuracy. This calculation is imperative for a consistent evaluation of experimentally measured mixing parameters since the coefficient functions of the effective Hamiltonian for B0-B(-)0 mixing are known at NLO. We find that radiative corrections violate factorization at NLO; this violation is under full control and amounts to 10%. The resulting value of the B parameter is found to be B(B)(m(b))=1+0.1(PT)-0.05(non-PT).
authors: Institut für Physik, Johannes-Gutenberg-Universität, Staudinger Weg 7, D-55099 Mainz, Germany.
authors: J G
authors: JG
authors: Körner
authors: A I
authors: AI
authors: Onishchenko
authors: A A
authors: AA
authors: Petrov
authors: A A
authors: AA
authors: Pivovarov