The oblique S parameter in higgsless electroweak models

TL;DR

This paper calculates the oblique S parameter at one-loop level in Higgsless electroweak models using an effective Lagrangian with resonances, applying short-distance constraints and dispersive methods.

Contribution

It provides a detailed one-loop computation of the S parameter in Higgsless models with a general effective Lagrangian including vector and axial-vector resonances.

Findings

One-loop S parameter estimation consistent with short-distance constraints.

Implementation of a chiral symmetry breaking pattern with resonances.

Application of dispersive approach for electroweak precision parameters.

Abstract

We present a one-loop calculation of the oblique S parameter within Higgsless models of electroweak symmetry breaking. We have used a general effective Lagrangian with at most two derivatives, implementing the chiral symmetry breaking SU(2)_L x SU(2)_R -> SU(2)_{L+R} with Goldstones, gauge bosons and one multiplet of vector and axial-vector resonances. The estimation is based on the short-distance constraints and the dispersive approach proposed by Peskin and Takeuchi.