On the observable spectrum of theories with a Brout-Englert-Higgs effect

TL;DR

This paper classifies the physical spectra of gauge theories with various Higgs sectors, highlighting discrepancies from elementary particles, especially in GUT-like models, due to the limitations of the Fr"ohlich-Morchio-Strocchi mechanism.

Contribution

It provides a comprehensive classification and prediction of the observable spectrum in generalized gauge theories with Higgs sectors, extending beyond the standard model.

Findings

Discrepancies between elementary fields and physical particles are common in extended gauge theories.

The spectrum in GUT-like theories can significantly differ from elementary field predictions.

The Fr"ohlich-Morchio-Strocchi mechanism's applicability varies across different gauge theories.

Abstract

The physical, observable spectrum in gauge theories is made up from gauge-invariant states. The Fr\"ohlich-Morchio-Strocchi mechanism allows in the standard model to map these states to the gauge-dependent elementary $W$, $Z$ and Higgs states. This is no longer necessarily the case in theories with a more general gauge group and Higgs sector. We classify and predict the physical spectrum for a wide range of such theories, with special emphasis on GUT-like cases, and show that discrepancies between the spectrum of elementary fields and physical particles frequently arise.