Can Color Singlets Be Formed for Baryons and Mesons?

[nigelscott]

I am trying to conceptually understand how form a color singlet for baryons and mesons. For example, the Wikipedia article http://en.wikipedia.org/wiki/Isospin shows how to construct the proton and neutron states in terms of isospin and spin. How does one create a color singlet corresponding to these states?

 

[Orodruin]

Each of the valence quarks carry a colour charge. The completely anit-symmetric colour state containing three objects in the fundamental (3) representation of SU(3) is a colour singlet.

 

[ChrisVer]

The color (r,g,b) symmetry is pretty much like the flavor symmetry for 3 flavors (u,d,s)...
So you form a singlet out of colors, in the same way you can form a singlet of three flavors (which is antisymmetric) ...

 

[nigelscott]

yes, I understand the formation of the color singlet from 3 x 3 x 3 = 1 + 8. What I don't understand is how you create a proton wavefunction that embodies spin 1/2, isospin 1/2 and is colorless. In the Wikipedia article, the wf is the product of 3 matrices. To create a colorless photon do you just multiply these by some kind of 'color' matrix that produces the desired result?

 

[Orodruin]

The state belongs to the tensor product space of the single particle state spaces, which in turn are tensor products of the spin, isospin, and colour states, as well as with the spatial state.