Heavy states and electroweak effective approaches

TL;DR

This paper explores how effective field theories, specifically the electroweak effective theory, can be used to connect potential new heavy states with observable low-energy constants, constraining resonance masses based on experimental data.

Contribution

It introduces a method to relate high-energy resonance parameters to low-energy constants within the electroweak effective theory framework, improving constraints on new physics.

Findings

Boundaries on resonance masses derived from low-energy constants.

Effective resonance Lagrangian couples SM states to new resonances.

Constraints consistent with current experimental data.

Abstract

The existence of a mass gap between the Standard Model (SM) and possible new states encourages us to use effective field theories. Here we follow the non-linear realization of the electroweak symmetry breaking: the electroweak effective theory (EWET), also known as Higgs effective field theory (HEFT) or electroweak chiral Lagrangian (EWChL). At short distances an effective resonance Lagrangian which couples the SM states to bosonic and fermionic resonances is considered. After integrating out the resonances and assuming a well-behaved high-energy behavior, we estimate or bound purely bosonic low-energy constants in terms of only resonance masses. Current experimental information on these low-energy constants allows us to constrain the high-energy resonance masses.