# The spin-flavor wavefunction of Sigma+

• I
Hi, guys.

If I want to write the spin-flavor wavefunction of ##\Sigma_+## starting only from knowing that the quark content of the proton is ##uud##, how can I procced?
I started by applying the ladder operators in order to get the baryon octet vertexes. I am now having problems with:
1. determining the flavor wavefunction for the center octet states (including ##\Sigma_+##).
2. determining the spin wavefunction for ##\Sigma_+##. Even if I suppose that the its spin state is ##|1/2,1/2\rangle##, there is more than one way for this to happen when we combine 3 spin 1/2 quarks...
Does anyone know a text where I can find something like this done in a comprehensive and detailed way? Or, alternatively, can you tell me a way to do it?

ChrisVer
Gold Member
Aren't sigma baryons strange ones? Are you using an SU(3) flavor symmetry?
As for the quarks they would be uus ? If you have more than 1 combination then you write them all, as you did for the proton [when you had the mixed symmetric states].
the flavor states can be obtained in a similar way by combining u,u and s.

The problem is that I did not understand the derivation of the proton wavefunction also: I found Griffiths, and for that matter every other text I found on the subject, quite confusing. Do you happen to know a place where it is clearly and thoroughly explained?

Using Thomson's book I understood the derivation of the proton spin-flavour wavefunction. I will try to apply what I learned to this case.

ChrisVer
Gold Member
what is confusing?

what is confusing?
To make myself clear, I posted my attempt. I arrived at the correct wavefunction, but I have a problem with it: even though it seems symmetric, I would expect it to be only mixed symmetric (only symmetric in 1,2), since ##X## is only symmetric in 1,2 and ##\phi## is completely symmetric...

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ChrisVer
Gold Member
Why is phi symmetric? aren't you using a uds? I am sorry but I don't see why you wouldn't consider the antisymmetric singlet.

I am sorry but I don't see why you wouldn't consider the antisymmetric singlet.
When determining ##X##?

ChrisVer
Gold Member
when determining Phi...
you should have a symmetric one (in the triplet I=1 combination) : $uds + dus$
and an antisymmetric one (in the singlet I=0 combination) : $uds - dus$
they both correspond to I3=0

Meir Achuz
Homework Helper
Gold Member
Look at look at PR 172, 1807 for simple spin – flavor wave functions for baryons.

Look at look at PR 172, 1807 for simple spin – flavor wave functions for baryons.
What is PR?

vanhees71