Dynamical Scenarios for $SU(2)_c$ Symmetric New Physics Interactions

We study a picture of effective interactions among the $W$ and Higgs bosons which is consistent with the precision tests at present energies, and at the same time allows for large observable New Physics (NP) effects in the bosonic sector. Toy dynamical models containing new heavy particles are used to indicate how such a picture could be created by integrating out the heavy particles. In these models custodial $SU(2)_c$ symmetry is realized at a certain large scale $\Lambda_{NP}$, either naturally or at a certain limit of a single coupling. In the derivation of the effective lagrangian we keep operators of dimension up to six. These operators involve only the known gauge boson and Higgs particles. They provide a valid description of NP up to an energy scale which is just below the mass of the new heavy degrees of freedom.