Assertion: muon's mass | /r/HasAspect | a field origin
Facets:
value: according to contemporary theory
type: OTHER
Source sentences:
text: The existence of μ-e universality raises for the theory of elementary particles an important and as yet unresolved problem: since, according to contemporary theory, the mass of particles has a field origin—that is, is determined by the interactions in which a particle participates—