Particle Octet: Explaining No Spin 1/2 Particles

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Discussion Overview

The discussion revolves around the properties of spin 1/2 particles in the context of quark combinations, specifically addressing the particle octet and the implications of quark statistics and wavefunctions. Participants explore theoretical aspects related to the symmetry of wavefunctions and the statistical behavior of quarks.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions the validity of a statement regarding the inability to have three identical quarks in a spin 1/2 state due to symmetry requirements.
  • Another participant clarifies that quarks are fermions and follow Fermi-Dirac statistics, emphasizing the complexity of the total wavefunction which includes spin, spatial, and color dependencies.
  • A participant notes that the exercise in the book does not yet address color and suggests that it implies quarks appear to follow boson statistics, which they consider a minor point.
  • Laura seeks feedback on the wavefunctions she developed for particles with uds quarks, describing them as linearly independent and symmetrical.

Areas of Agreement / Disagreement

Participants express disagreement regarding the interpretation of quark statistics and the implications for the wavefunctions of spin 1/2 particles. The discussion remains unresolved as differing viewpoints on these concepts are presented.

Contextual Notes

Participants highlight the complexity of the total wavefunction for quarks, which includes multiple dependencies that are not fully addressed in the initial exercise. There is an acknowledgment of the limitations in the exercise's treatment of color and statistics.

lark
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Would anyone like to tell me if I did this right? see attached .gif. It's an exercise in a book I'm reading, about explaining why there aren't any spin 1/2 particles with uuu, ddd, or sss quarks, 1 each of uud, uus, etc., and 2 of uds quarks: the particle octet.
Laura
 

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I can't make out the thumbnail or make sense of it.
You can't have three u quarks in a spin 1/2 state, because the spin 1/2 state has mixed symmetry, and only purely symmetric states are allowed for three identical quarks in a completely symmetric spatial state.
 
lark said:
Would anyone like to tell me if I did this right? see attached .gif. It's an exercise in a book I'm reading, about explaining why there aren't any spin 1/2 particles with uuu, ddd, or sss quarks, 1 each of uud, uus, etc., and 2 of uds quarks: the particle octet.
Laura

The first statement makes no sense. You say that quarks follow Bose statistics even though they are fermions!

Of course they follow Fermi-Dirac statistics!
But it's a bit complicated because the total wavefunction has a spin dependence, a spatial dependence but a colour dependence as well. All this must be taken into account.
 
nrqed said:
The first statement makes no sense. You say that quarks follow Bose statistics even though they are fermions
That exercise is before the book talks about color, it just says the quarks (appear to) follow boson statistics.

Other than that, which is kind of a minor point, does anyone have any comments? Are the wavefunctions for the particles with uds quarks right? That was mostly what I was asking about, because I just came up with a couple of wavefunctions that are linearly independent and look nice and symmetrical.

Laura
 
Last edited:

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