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Name:  Ricardo
Status:  student
Age:  19
Location: N/A
Country: N/A
Date: 2000-2001


Question:
Why 8 gluons?


Replies:
As far as I know, gluons have a color charge, it is the combination of a color ith an anticolor.

I have read in many places that due to SU(3) simmetry properties, there are only 8 gluons, but I can't figure out wich one are them.

Using a simple combination, gluons could be red-antiblue, red- antigreen, red-antired, blue-antired, blue-antigreen, blue-antiblue, green-antiblue, green-antired and green-antigreen. (9 kinds of gluons)

Since three of them have a white color (red-antired, blue-antiblue and green-antigreen) I can eliminate them, but then I only have 6 gluons.

Where does the number 8 come from?

To be truly white, the gluon must be red-antired, green-antigreen, AND blue-antiblue. Based on the mathematics of wave function probability, the white gluon is (red-antired + blue-antiblue + green-antigreen)/sqrt(3). The square root of three is to keep things the correct size. There are tow wave functions that are not actually white: (red-antired - green-antigreen)/sqrt(6) and (red-antired + green-antigreen - 2*blue-antiblue)/sqrt(6). These two gluons can interact without changing the color of a quark, but they are not truly white. A white particle can have no preference for red, green, or blue.

Kenneth Mellendorf



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