QCD and confinement specify that hadrons must be color-neutral. My understanding is that this means you can have mesons (quark + antiquark) or baryons with 3 quarks, one of each color: Red+green+blue=neutral.
In a meson, does the color of the quark and antiquark matter? Must a red quark be paired with a red antiquark; or does the color change constantly due to the exchange of gluons which also carry color charg?
[Physics] Does the color of a quark matter in a meson
color-chargemesonsquantum-chromodynamics
Related Solutions
It is not clear how much you know about elementary particles and interactions.
This is the table of elementary particles in the standard model of physics
And these are the forces with which the elementary particles interact and finally create matter as we see it everyday.
The quarks within the proton and neutron interact mainly with the strong force, because they are so close to each other that the other forces are insignificant to first order.
This is a simplified diagram of what happens in a proton, which is made up of three quarks.
The Tiny White Lie: Wikipedia's sterotypical image of a proton as two up quarks and a down quark bound together.
The reality is more complicated because of the strong force:
Snapshot of a proton -- and imagine all of the quarks (up,down,and strange -- u,d,s), antiquarks (u,d,s with a bar on top), and gluons (g) zipping around near the speed of light, banging into each other, and appearing and disappearing. (M.Strassler 2010)
The quarks and gluons exchange color charge when interacting in the soup in such a manner as to keep the whole proton color neutral.
The bottom line is that the quarks change color because they are interacting with each other and a sea of quarks and antiquarks within the nucleus due to the strong force, and interaction=color-charge exchanges also.
( The interactions are similar but not the same with molecules in a liquid, they keep exchanging photons interacting with each other, but photons carry no charge, whereas gluons carry color charge )
One is talking quantum mechanics and attributed quantum numbers to elementary particles.
A simple quantum number is charge and it it assigned to quarks ( and antiquarks) as +/-1/3 or +/-2/3 as in the table
Charge is connected with the electromagnetic force.
Flavor is assigned as a quantum number to each quark, and it is connected with the weak interaction.
Each quark at the same time is connected with the strong color force of quantum chromo dynamics. So it can also come in the three color quantum numbers, for identification called red blue and green ( analogous to the weak Strange Charm Bottom Top).
The identifications are not random, they are within the SU(3)xSU(2)xU(1) group representations and algebra of the standard model of particle physics.
The quark forces are attractive only in "colorless" combinations .
Attractive is a wrong attribute. Color is always attractive, but it can be "nullified" in certain color combinations so that stable bound states of quarks appear, as with the rest of the quote.
Flavor characterizes the weak interactions of the quarks. Color the strong ones.
Best Answer
The color charges are paired (color with anticolor), but there's no gauge invariant meaning to the identification of the color (RGB). And due to QM, the quark states are a superposition over all the colors (and antiquarks over the anticolors). The wikipedia page is pretty clear: http://en.wikipedia.org/wiki/Color_charge. As it notes, you also can't distinguish a color from a certain superposition of the two non-complementary anticolors (e.g., R from a combination of anti-G + anti-B).