Interplay of t --> b W Decay and B_q Meson Mixing in Minimal Flavor Violating Models

TL;DR

This paper explores how anomalous top quark decays and B meson mixing, within a minimal flavor violation framework, can reveal new physics effects, with potential deviations detectable at the LHC.

Contribution

It provides a model-independent analysis of anomalous t W d_j interactions affecting B meson mixing and top decay observables, linking flavor physics and collider signatures.

Findings

Anomalous t W d_j interactions can significantly affect B meson mixing.

W helicity fractions in top decays can deviate up to 30% from Standard Model predictions.

Deviations in F_L are within the reach of LHC precision measurements.

Abstract

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 t W d_j interactions as a possible source of new effects in B_{d,s} - bar B_{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,s} meson mixing and evolving it down to the B-mass scale, we extract the preferred ranges of the anomalous t W d_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 --> b W decays and find that the W helicity fractions F_{L,+} 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.