The colors of the quarks

1. Jun 20, 2008

abdullahbameh

the colors of the quarks!!!!

can any body tell me
if the colors of the quarks does really exist (( green , blue , red)) ((anti green, anti blue, anti red ))) or it is just a way to avoid the exclusion principle??
and they are fermions means they can not exist in the same state and have half integral spin.

Last edited: Jun 20, 2008
2. Jun 20, 2008

humanino

The number of colors can be measured in different ways. On way, you collide electrons and positrons, and you look at the ratio of the probability for a quark-antiquark pair, to the probability to get (say) a muon-antimuon pair (see Drell-Yan process as well, but this is more complicated for this purpose). This is sensitive to both the number of generations (flavor) involved, which depends on energy, and the number of colors. This definitely rules out any scenario except 3 colors. Another way, the neutral pion lifetime, is quite unambiguous as well. Then, the physics of jets as come to such a richness that I cannot summarize now. For instance, the scaling violations in jet production, we can even compare quark and gluon jets, everything points to SU(3).

3. Jun 20, 2008

tiny-tim

Hi humanino!

But do the colours exist as discrete characteristics, in the same way that charge does?

Charge can be either + or -, but not, for example, halfway between + and -.

Can a quark have a colour, for example, halfway between red and green?

4. Jun 20, 2008