This class is used to deliver both information defined in the Standard Model (or potentially just QED X QCD) as a low-energy effective theory (as opposed to correspending information defined in a high-energy model) as well as a corresponding high energy theory.
Implementations for type_equivalency class, a simple container used for storing info about which types have been defined as equivalent for depencency resolution purposes.
Simple function for returning SM Higgs partial and total widths as a function of virtuality, as read from data files from CERN Yellow Paper arXiv:1307.1347.