QCD, a part of standard model?

BuckeyePhysicist
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How is it not an exactly accurate understanding that QCD is a part/sector of the standard model of particle physics ? Or, it actually is?
 
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BuckeyePhysicist said:
How is it not an exactly accurate understanding that QCD is a part/sector of the standard model of particle physics ? Or, it actually is?


It is. Quarks feel both the elecromagnetic force (they're electrically charged) and the weak force (they change identities, manifesting weak decay, and emitting both weak bosons and leptons), and the Salam-Weinberg unified Electroweak force therefore acts on them. Because these events are weak compared to the strong (color) force, it is sometimes permissible and possible to consider the QCD model, or even its first flavor (up and down quarks and their antiparticles) in isolation, but this is in no way intended to imply that for example, beta decay doesn't exist!
 
Moreover, the experimental fitting of scattering amplitudes gets its right value if we have a multiplicity three for the quarks. So definitively SU(3) is included in the standard model.
 

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