The fate of <em>irrelevant</em> operators in Higgs-less effective theories

por Johannes HIRN (IFIC,Valencia)

martes 26 oct. 2004 12:00 → 13:00 Europe/Madrid

Sala Seminarios IFIC (Edf. Institutos de Investigación)

When constructed with Standard Model fields, the effective operators that generate lepton-number violation, non-universal fermion-vector couplings and contributions to the $S$ and $T$ parameters, are \it{irrelevant}. This is not the case in the absence of a light Higgs boson: in the low-energy effective theory for Higgs-less electroweak symmetry breaking (defined as a momentum expansion with order-by-order renormalization), the corresponding operators appear at the leading (chiral) order. To take into account the experimentally observed suppression of the incriminated terms, we propose a consistent expansion in which they are relegated to higher orders.