A warning to readers: whereas originally the denomination “Standard Model Extension” was universally used to describe a
framework implementing the restriction to powercounting-renormalizable correction terms, recently (see, e.g., Ref. [123
]) some
theorists describe as “Standard Model Extension” the generalization that includes correction terms that are not powercounting
renormalizable, while they describe as a “Minimal Standard Model Extension” the case with the original restriction to
powercounting-renormalizable correction terms. Still, even as I write this review, many authors (in particular the near totality
of experimentalists involved in such studies) continue to adopt the original description of the “Standard Model
Extension”, restricted to powercounting-renormalizable correction terms, and this may create some confusion
(for example experimentalists reporting results on the “Standard Model Extension” are actually, according to
the terminology now used by some theorists, describing experimental limits on the “Minimal Standard Model
Extension”).