Question

How well is the $\rho$ and $\omega$ coupling universality measured?

Answer 1

Hello user☺☺

These ideas died away with QCD, when the

ρ

ρ

could no longer be considered an elementary particle or an elementary string state. But they were revived somewhat in the 1980s, as people began to consider hidden local symmetry, where there is an infinite tower of gauge symmetries. Hidden gauge symmetry seems sort of silly and umotivated at first, but the proper motivation is within string theory, and AdS/QCD explains how this picture can emerge, the tower of gauge symmetries are a Kaluza-Klein tower in an extra dimension, and the local-hidden-symmetry picture can appear naturally from strings. This makes all this stuff interesting again, both theoretically and experimentally.

Answer 2

In attachment.................,