Speaker
Prof.
Ulrich Nierste
Description
Abstract:
I present new results for the QCD corrections to the leading term in the
1/m_b expansion of the B-B-bar decay matrix element, which is now
completely determined to three-loop order. These results permit a more
precise Standard-Model prediction of the width differences Delta
Gamma_{d,s} and the CP asymmetries in flavour-specific
(e.g. semi-leptonic) decays, a_{fs}^{d,s}, for the Bd-Bd-bar and
Bs-Bs-bar mixing complexes. The perturbative uncertainty of the
well-measured Delta Gamma_s now matches the experimental error. I
further discuss the benefits of better measurements of Delta Gamma_d and
a_{fs}^d, which will provide novel insight into possible new physics in
Bd-Bd-bar mixing.
