Effects of the Electroweak Symmetry Breaking Sector in Rare B and K Decays

The effects of the electroweak symmetry breaking sector in rare $B$ and $K$ decays are considered in the presence of new strong dynamics at a large energy scale. In the context of the low energy effective lagrangian of the symmetry breaking sector, we focus on the contributions that are not constrained by bounds on oblique corrections or anomalous triple gauge boson vertices. We find that these have very little effect in $b\to s\gamma$, but potentially large contributions appear in $b\to s\ell^+\ell^-$ and $b\to s\nu\bar\nu$ as well as in $b\to s g$ processes. Deviations from the standard model in rare $K$ decays such as $K^+\to\pi^+\nu\bar\nu$ and $K_L\to\pi^0\nu\bar\nu$ are shown to be correlated with the ones in the $B$ modes. The distinct resulting pattern of deviations from the standard model in rare decays is a characteristic feature of a strongly interacting electroweak symmetry breaking sector.