Improved analysis of the bounds from the electroweak precision tests on the 4-site model

TL;DR

This paper provides a comprehensive analysis of electroweak precision tests on the 4-site Higgsless model, revealing constraints on extra gauge bosons and their potential detectability at the LHC.

Contribution

It introduces a complete numerical method for analyzing electroweak bounds on the 4-site model, considering correlations among measurements and going beyond previous approximations.

Findings

Extra gauge bosons must be heavier than 250 GeV.

Couplings of new gauge bosons can be comparable to SM couplings.

The 4-site model is not fermiophobic, allowing potential discovery at LHC.

Abstract

We present a new complete analysis of the electroweak precision observables within the recently proposed 4-site Higgsless model, which is based on the SU(2)_L x SU(2)_1 x SU(2)_2 x U(1)_Y gauge symmetry and predicts six extra gauge bosons, W_{1,2} and Z_{1,2}. Within the epsilon_i (i=1,2,3,b) parametrization, we compute for the first time the EWPT bounds via a complete numerical algorithm going beyond commonly used approximations. Both epsilon_{1,3} impose strong constraints. Hence, it is mandatory to consider them jointly when extracting EWPT bounds and to fully take in to account the correlations among the electroweak precison measurements. The phenomenological consequence is that the extra gauge bosons must be heavier than 250 GeV. Their couplings to SM fermions, even if bounded, might be of the same order of magnitude than the SM ones. In contrast to other Higgsless models, the 4-site model is not fermiophobic. The new gauge bosons could thus be discovered in the favoured Drell-Yan channel already during the present run of the LHC experiment.