Negative S parameter from holographic technicolor

We present a new class of 5D models, Holographic Technicolor, which fulfills the basic requirements for a candidate of comprehensible 4D strong dynamics at the electroweak scale. It is the first Technicolor-like model able to provide a vanishing or even negative tree-level S parameter, avoiding any no-go theorem on its sign. The model is described in the large-N regime. S is therefore computable: possible corrections coming from boundary terms follow the 1/N suppression, and generation of fermion masses and the S parameter issue do split up. We investigate the model's 4D dual, probably walking Technicolor-like with a large anomalous dimension.
Version accepted for publication in PRL. Introduction and conclusion extended