# Analogy for magnetism in the nuclear strong force?

1. ### pantheid

50
Whenever people begin to explain the nuclear strong force, they relate it to electricity. I was wondering if color charges, besides also interacting with one another in a way thats analogous to electricity, can also interact in a way thats analogous to magnetism. I have asked some professors and they said "maybe," but were unfamiliar with it.

2. ### The_Duck

997
Yes, the strong force involves both "chromoelectricity" and "chromomagnetism." One of the deep insights of special relativity is that electricity and magnetism are two aspects of the same thing, one total electromagnetic field. Similarly there is a chromoelectric field and a chromomagnetic field that are both aspects of one total color field.

3. ### dauto

There are in fact eight of each (though in QFT the 4-potential is most often considered the fundamental fields and the electromagnetic field is considered a derived field.)

4. ### Bill_K

4,157
Do quarks have an anomalous chromomagnetic moment?

5. ### pantheid

50
sorry, but eight of what exactly?

6. ### pantheid

50
And can someone explain how a chromomagnetic field would work if all color-charges must be in bound states?

7. ### RGevo

90
There are colour effects inherent in descriptions of particle collisions.

See the Lund string model for example. Colour effects are all around at the Lhc where coloured objects are interacting.

Some of these models which include dipole colour interactions are approximations of things we still haven't calculated to high enough accuracy yet.

8. ### RGevo

90
And these things happen after a collision before these coloured objects form into bound objects(hadronization which occurs at a later time scale)

9. ### dauto

Eight independent set of fields, each equivalent (up to a certain point) to the set of electromagnetic fields.

10. ### The_Duck

997
I assume so; for example in QCD at one loop you can draw a diagram correcting the quark-quark-gluon vertex that looks exactly like the one-loop QED diagram that corrects the electron-electron-photon vertex and which gives rise to the anomalous magnetic dipole moment of the electron. So at least in perturbation theory you can use that to calculate an anomalous chromomagnetic dipole moment.

That might only work perturbatively, though. In QED you can define the magnetic dipole moment as the derivative of the energy of the one-electron state with respect to the external magnetic field. But in QCD quarks are confined so it's hard to speak of a one-quark state. Maybe nonperturbatively the magnetic dipole moment of a quark is ill-defined?

The fields are also confined; within a proton, say, there is a bundle of quarks all bound together by chromoelectric and chromomagnetic fields. These fields cannot extend far outside the proton, just as the quarks cannot stray outside proton.

Why are you worried about chromomagnetic fields as opposed to chromoelectric fields?

Last edited: Oct 19, 2013
11. ### pantheid

50
The fields are also confined; within a proton, say, there is a bundle of quarks all bound together by chromoelectric and chromomagnetic fields. These fields cannot extend far outside the proton, just as the quarks cannot stray outside proton.

Why are you worried about chromomagnetic fields as opposed to chromoelectric fields?[/QUOTE]

I think the question of how they work is pretty interesting, and I want to include some description of it in a paper I'm writing for class.

12. ### clem

1,276
Yes, it leads to a strong spin-spin interaction just like the atomic hyperfine interaction.
This has been known since the start of the quark model, but seems to have been forgotten.