Heavy resonances and the oblique parameters S and T

TL;DR

This paper investigates how heavy resonances in a non-linear electroweak symmetry breaking model affect the oblique S and T parameters, constraining resonance masses to be above 3 TeV through one-loop calculations.

Contribution

It provides a one-loop analysis of oblique parameters in a non-linear Higgs sector with heavy resonances, extending previous simplified models.

Findings

Resonance masses are constrained to be above 3 TeV.

The oblique parameters are consistent with previous estimates.

Heavy resonances influence electroweak precision observables.

Abstract

It has been confirmed experimentally the existence of a mass gap between Standard Model (SM) and eventual Beyond Standard Model (BSM) fields. Therefore, the use of effective approaches to search for fingerprints of New Physics is very appealing. A non-linear realizations of the Electroweak Symmetry Breaking is considered here, where the Higgs is a singlet with free couplings and the SM fields are also coupled to bosonic heavy resonances. A one-loop-level calculation of the oblique S and T parameters is presented here. This analysis allows us to constrain resonance masses to be above the TeV scale, $M_R\!>\! 3\,$TeV, in good agreement with our previous determinations, where these observables were computed with a more simplified Lagrangian.