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friend
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Each quark as a flavor charge and a color charge. Are these two properties totally independent of each other? Thanks.
Quark flavor and color independent?
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In summary: But it does seem to suggest that a gluon travels only from one type of quark to its anti-quark version.No.
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mfb
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Yes.
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friend
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So, for example an up quark, u, can have any of the following colors: red, green, blue, anti-red, anti-green, and anti-blue? And an anti-up quark, u, can have any of those colors or anti-colors, too. Is this right? Thanks.mfb said:
PS. how do I do an overstrike in this forum?
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No, a quark cannot carry anti-colour. It is in the ##\bf 3## representation of SU(3), not in the ##\bf \bar 3## representation.friend said:
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friend
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OK. So now I'm learning something (I think). Correct me if I'm wrong. Quarks of any flavor or anti-flavor, e.g., ##u## or ##\bar u##, can only have red, greed, or blue color. But only the gluons can have anti-color in combination with a color. Is this right? Thanks ever so much.Orodruin said:
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friend
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I think there needs to be a correction. I found this site and similar that says quarks have a color charge (red, green, blue), but anti-quarks have anti-color (anti-red, anti-green, anti-blue). The link given is to a site claiming to be sponsored by DOE and NSF. If this is not credible, can someone point me to a more reliable source that confirms this? Thanks.friend said:
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Yes, anti-quarks transform according to ##\bf\bar 3##. Gluons transform according to the adjoint representation ##\bf 8## and gluons are therefore traceless colour-anticolour combinations.
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friend
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On the Wikipedia site for quarks, I found this diagram. There is no reference to individual quarks. But it does seem to suggest that a gluon travels only from one type of quark to its anti-quark version. For example, in the diagram, the ##g####g\bar b## gluon is between the ##q####g## quark and the ##\bar q####b## anti-quark. Does this mean that the ##g####g\bar b## gluon must travel between any quark of color green and any anti-quark of color blue? (I thought anti-quarks can only have anti-color.) Or does this mean that the ##g####g\bar b## gluon can only travel between a ##u## quark and a ##\bar u## anti-quark, or can only travel between a ##d## quark and a ##\bar d## anti-quark, or can only travel between a ##s## quark and a ##\bar s## anti-quark, etc? I'd appreciate any help in reading this diagram. Thanks.
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mfb
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No, and I don't know how you got that idea. Check Feynman diagrams of gluon exchange.friend said:
No.friend said:
Correct.friend said:
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That diagram is group-theoretical in origin and shows the charges under the diagonal SU(3) generators. It has nothing to do with gluons "travelling" between quarks. In order to understand the diagram you need to understand group representation theory, which it is not clear to me from this thread if you do or not.
Also note that when you encounter Feynman diagrams they are really not pictures of particles flying around (although physicists will often talk about them in a manner that might suggest that to a layman), they are graphical representations of mathematical terms in a series expansion. There is also some caveats for representing colour in Feynman diagrams ...
Also note that when you encounter Feynman diagrams they are really not pictures of particles flying around (although physicists will often talk about them in a manner that might suggest that to a layman), they are graphical representations of mathematical terms in a series expansion. There is also some caveats for representing colour in Feynman diagrams ...
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friend
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I don't see the problem. Use whatever language you're would like. I'm sure things can get complicated with superpositions and different basis. But the language used in the figure means something. Correct me if I'm wrong, but it seems obvious that ##\bar q## is an anti-quark whereas ##q## is a quark. The down pointing blue triangle must mean anti-blue, since anti-quarks on take only anti-colors. And the ##g\bar b## in the symbol ##g####g\bar b## seems to indicate what color is being changed by that gluon. If someone could explain what pair of quarks can possibly be changed by ##g####g\bar b## and how they are changed, this would be very helpful.
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friend
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This video seems to be in the same spirit as the diagram above. The author is Dr. Vitaly Velizhanin. I'm sure it's probably an oversimplification. But is it actually wrong? Does it neglect other possible interactions with any of the gluons it depicts? For it seems to depict a gluon of a certain color/anti-color coming from only one type of quark and being accepted by only one other type of quark. Thanks.
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1. What is quark flavor and color independence?
Quark flavor and color independence is a fundamental concept in particle physics that describes how quarks, which are subatomic particles, interact with each other. It states that the properties of quarks, such as their mass and charge, are independent of their flavor (type) and color (a property that describes how quarks interact through the strong nuclear force).
2. Why is quark flavor and color independence important?
This concept is important because it helps us understand how quarks interact and form different types of particles, such as protons and neutrons. It also provides a framework for understanding the fundamental forces and interactions within the nucleus of an atom.
3. How was quark flavor and color independence discovered?
Quark flavor and color independence was first proposed in the 1960s by physicists Murray Gell-Mann and George Zweig, and was later confirmed through experiments at particle accelerators, such as the Stanford Linear Accelerator Center (SLAC) and the Large Hadron Collider (LHC).
4. Are there any exceptions to quark flavor and color independence?
While quark flavor and color independence is a fundamental principle, there are some exceptions. For example, in extreme conditions, such as in the early universe or within a neutron star, the properties of quarks can change and they may no longer behave independently of each other.
5. How does quark flavor and color independence relate to the Standard Model of particle physics?
Quark flavor and color independence is one of the key principles of the Standard Model, which is the current theory that describes the fundamental particles and forces of the universe. It is essential for the model to accurately predict the behavior of particles and their interactions.
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