Interplay of t → bW decay and Bd,s(B)over-bard,s mixing in Minimal Flavor Violating Models

Precise measurements of the top quark decay properties at hadron colliders offer interesting new possibilities of testing the standard model. At the same time, recent intriguing experimental results concerning CP violation in the B-d and B-s systems have stimulated many studies of physics beyond the standard model. We investigate anomalous tWd(j) interactions as a possible source of new effects in B-d,B-s-(B) over bar (d,s) oscillations within a model independent approach based on the assumptions of Minimal Flavor Violation. After matching our effective operators onto the low-energy effective Lagrangian describing B-d,B-s meson mixing and evolving it down to the B-mass scale, we extract the preferred ranges of the anomalous tWd(j) interactions at the weak scale. These values are then compared to previously considered constraints coming from the rare radiative B -> X-s gamma decay. Finally, we reconsider the associated effects in the t -> bW decays and find that the W helicity fractions F-L,F-+ can deviate by as much as 15%, 30% from their standard model values, respectively. The deviations in F-L in particular, can reach the level of expected precision measurements at the LHC. (C) 2011 Elsevier B.V. All rights reserved.