Probing anomalous tWb interactions with rare B decays
  Precision studies of top quark properties are currently underway at the LHC and Tevatron colliders with the prospect of probing anomalous t-W -b interactions. In the mean time, recent experimental results for the B_{d,s} - \bar{B}_{d,s} oscillation observables, the branching ratio B_s->\mu^+\mu^-, as well as the forward - backward asymmetry in B->K\starl^+l^-, accompanied by the accurate theoretical predictions for the relevant observables obtained within the SM motivate a combined study of these observables in the presence of anomalous t - W - b vertices. We investigate contributions of such anomalous couplings to the B->X_s l^+l^- decay mode, and combining them with the modifications of the B_{d,s} - \bar{B}_d,s, B->X_s{\gamma} observables, we determine indirect bounds on the real and imaginary parts of the anomalous t - W - b interactions. We find these to be mostly superior to present direct constraints coming from top decay and production measurements at the LHC and Tevatron. Finally, we predict the allowed effects in the branching ratios of the B_s->\mu^+\mu^- and B->K^{(*)}\nu \bar{\nu}, as well as the forward-backward asymmetry in B->K^*l^+l^-. We find that improved knowledge of these observables in the future could further constrain some of the anomalous tWb interactions. 
Jure Drobnak, Svjetlana Fajfer and Jernej F. Kamenik
hep-ph hep-ex