Electroweak chiral Lagrangians and the Higgs properties at the one-loop level

Abstract

In these proceedings we explore the use of (non-linear) electroweak chiral Lagrangians for the description of possible beyond the Standard Model strong dynamics in the electroweak sector. Experimentally one observes an approximate electroweak symmetry breaking pattern $SU(2)_L\times SU(2)_R/SU(2)_{L+R}$. Quantum Chromodynamics shows a similar chiral structure and, in spite of the differences (in the electroweak theory $SU(2)_L\times U(1)_Y$ is gauged), it has served for years as a guide for this type of studies. Examples of one-loop computations in the low-energy effective theory and the theory including the first vector and axial-vector resonances are provided, yielding, respectively, predictions for $\gamma\gamma\to Z_LZ_L,W^+_LW^-_L$ and the oblique parameters $S$ and $T$.