Spectrum of the SU(2) scalar-fermion-gauge system under the influence of the Brout-Englert-Higgs effect

TL;DR

This paper investigates the physical spectrum of a gauge-invariant SU(2) scalar-fermion-gauge system influenced by the Brout-Englert-Higgs effect using non-perturbative lattice methods, extending understanding of the FMS mechanism to fermionic observables.

Contribution

It provides the first non-perturbative lattice analysis of a fermionic gauge-invariant system under the FMS mechanism, identifying physical states and suitable simulation points for collider studies.

Findings

Determined the physical spectrum consistent with the FMS mechanism.

Identified simulation points for future scattering and collider analyses.

Extended the FMS mechanism understanding to fermionic sectors.

Abstract

Gauge invariance requires physical states to be composite, even in the weak sector of the Standard Model (SM). The Fr\"ohlich-Morchio-Strocchi (FMS) mechanism resolves this subtlety and predicts additional Higgs contributions in SM processes. While this has been supported by theoretical investigations in the bosonic sector, its impact on fermionic observables remains largely unexplored. We use non-perturbative lattice techniques within a gauge-invariant framework to study a proxy theory of the weak sector with dynamical fermions. We determine the physical spectrum of the theory and interpret the results in the context of the FMS mechanism. Additionally, we identify suitable simulation points for a scattering analysis as a first step toward cross-sections relevant to (future lepton) colliders.