Like the title say, does quark color matter in counting contributions in a early universe plasma (QGP), as when adding up the total plasma energy density, or is it just spin? The book I have (Pathria) only does one example and doesn't really firmly say one way or the other. I kind of thought it was to account for all degeneracy but the table in the book only has "spin degeneracy".
E.g.: $u_{total}(T) = X\,u_{\gamma}(T) = \left(2 + 8 + 7/2 \right)\,\frac{u_{\gamma}(T)}{2}$ where the terms are for, photons, gluons, and charm/strange quarks. (I know these together do not make sense, but it is just an example).
