Graduate Questions about magnetic monopoles

[phoenix95]

So far as I know there are no monopoles in the electro-weak sector of standard model. So people look for it in the GUT and SUSY sectors. However, they are predicted to be heavy(order of Planck mass). There have been studies from LHC attempting to detect monopoles. So here are my questions:

1. If monopoles are too heavy to be detected at LHC, then why look for them? Are there theories why predict them to be lighter than GUTs? Or am I missing anything?
2. Why all cosmology theories only talk about monopoles of GUTs? One can construct monopoles from SU(3) of strong interaction and/or flavor as well, can't they?

 

[Vanadium 50]

Should experimenters only look for things predicted by theory? We would never have discovered the muon that way.

 

[phoenix95]

I think I figured out the answers to my question:

2. Why all cosmology theories only talk about monopoles of GUTs? One can construct monopoles from SU(3) of strong interaction and/or flavor as well, can't they?

SU(3) of the color, doesn't intrinsically carry an electromagnetic charge. Or to put it more appropriately: The electromagnetic charge is constructed from flavor generators of SU(3) and not color. But the flavor symmetry is explicitly broken. Hence there are no monopoles in SU(3) (flavor or color).

1. If monopoles are too heavy to be detected at LHC, then why look for them? Are there theories why predict them to be lighter than GUTs? Or am I missing anything?

Well, if they do then it corresponds to a gauge group that has a weaker coupling compared to GUTs. It can also be viewed like this: GUTs simply present a falsifiable argument saying "Monopoles cannot be detected at present scales available", and the experiments are simply testing that.

I hope someone can correct me if I am wrong in any of the above.

Should experimenters only look for things predicted by theory? We would never have discovered the muon that way.

I absolutely agree. Experimenters should be the impudent brats as they are since otherwise theorists can only be writing fantasies.

 

[Demystifier]

GUT theories predict that monopoles are created at high energies (but not as high as Planck energy) at an early cosmological era. If so, they should be still visible in the present Universe (unless inflation diluted them).