Does the strength of the strong interaction depend on the colour of the quarks?

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Discussion Overview

The discussion revolves around the relationship between the colour charge of quarks and the strength of the strong interaction. Participants explore whether the strength of this interaction varies based on the colour of the interacting quarks, as well as the conceptual underpinnings of colour charge in quantum mechanics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that colour charge is necessary to avoid violating the Pauli exclusion principle when quarks are in the same state, questioning the link between colour and the attractive potential of the strong interaction.
  • Another participant asserts that the strength of the strong interaction is independent of colour, stating it is defined as such.
  • A different participant reiterates that the strength is colour independent but questions why colour is associated with the quantum number needed to address the Pauli exclusion principle.
  • One participant proposes that it is simpler to have a single property (colour) rather than introducing multiple properties to explain the strong force.
  • Another participant notes that if there were two different quantum numbers, one would expect to observe a different spectrum, referencing the formation of "white" singlets for unconfined particles.
  • A later reply warns that simply duplicating colour would complicate the antisymmetrization of the wavefunction.

Areas of Agreement / Disagreement

Participants express differing views on whether the strength of the strong interaction depends on the colour of the quarks. While some assert that it is independent, others question the rationale behind this definition and explore the implications of introducing multiple quantum numbers.

Contextual Notes

There are unresolved assumptions regarding the definitions of colour charge and its implications for the strong interaction, as well as the potential effects of introducing additional quantum numbers.

jeebs
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My understanding of colour so far is that if we had, say, a baryon with quark content uuu, we would need to invoke a new quantum number that would allow each quark not to be in the same quantum state to avoid violating the Pauli principle.

Now apparently this new quantum number is called colour charge, and is the source of the strong interaction in the way that electric charge is for electromagnetism. Two questions:
Why has it been decided that this thing we call colour is responsible for generating an attractive potential? Is it just that we do not assign colour to anything that doesn't involve quarks, and quarks are the only ones who participate in the strong interaction, so the two must be related?
Does the strength of the strong interaction vary between which quarks are doing the interacting, for example, does red and blue attract stronger than red and green etc?
 
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We name the thing that causes the strong force "color". It's true by definition.

The strength is color independent.
 
Vanadium 50 said:
We name the thing that causes the strong force "color". It's true by definition.

The strength is color independent.

but why have we linked what causes the strong force with the quantum number that had to be introduced to get around Pauli exclusion?
 
Occam. Why invent two new properties if only one will do?
 
Plus, if there were two different quantum numbers, we should observe a different spectrum, should we? Note the fundamental trick of obtaining "white" singlets for unconfined particles.
 
You will definitely have trouble antisymmetrizing the wavefunction if you blindly add a duplicate of color.
 

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