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

Abstract

The physical, observable spectrum in gauge theories is made up from gauge-invariant states. The Fröhlich-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.

Comments: 20 pages, 9 tables v3: Minor modification, version equivalent to published one v2: Intro extended, presentation reworked, 20 pages, 9 Tables