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Gluon color shift

  1. Jul 11, 2005 #1
    I had a thought the other day - following from general relativity, a photon experiences a gravitational red shift in frequency. Searching for a research project, I toyed with the idea of a chromodynamic red shift if a photon were to pass through a strong field. However, since the photon has no color charge, i could not see any kind of a shift occuring. Here is the question i pose: could a gluon undergo an analgous "colour shift" within a hadron?
  2. jcsd
  3. Jul 12, 2005 #2


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    The "colo(u)rs" in reference to gluons and quarks are merely labels. They have nothing to do with color for light. They could just as well be called cat, dog, and pig.
  4. Jul 12, 2005 #3


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    Red shift involves a change in frequency of light. I'm not aware of a weak force or strong force analog to frequency.
  5. Jul 19, 2005 #4
    Er no, the gluon's colour is not an actual colour, it is a quantumnumber that arises because of certain symmetry relations under which the physics of the strong force must be invariant. This is just like how the L-operator (J, more generally) arises because of invariance of wavefunction-probability under rotations in QM.

    Then keep in mind that the cosmological/gravitational red shift is not the same as the Doppler red shift which arises because of relative motion of two bodies. The first arises because of space time expansion. If the star is moving away from us during a rotation around another star for example, we see a Doppler like red shift, but again that is no gravitational redshift that arises because the star moves away with the expanding space time continuum.

    Last edited: Jul 19, 2005
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