# Symmetry of electromagnetism

1. Aug 28, 2004

### kurious

Quarks can't exist in isolation and the electric charge on quarks can't exist in isolation from the electric charges of other quarks either.The electric charge of leptons like the electron can exist in isolation.Isn't electromagnetism showing a kind of asymmetry here: symmetry could be restored if the electron was made of quarks!
The electron has a mass many times smaller than the rest masses of up and down quarks which are classified as light quarks.Light quarks have more gluons which account for most of the rest mass of hadrons that are composed of them.An electron made from quarks would be expected to have even more
gluons between its quarks than a proton.This would mean that the colour force would be stronger between quarks in an electron than between quarks in a proton.The residual colour force - the strong force - between electrons- would be expected to have a force carrier with a higher mass than the strong force carrier for hadrons, the meson (using Yukawa's argument for
force carriers).We would expect to observe electrons attracting or repelling one another at very short distances because of their residual colour force.
But the electric repulsion of one electron for another could swamp the effect,
so it goes unnoticed.Any thoughts on this - I'll try and do a calculation of
the forces later.

Last edited: Aug 28, 2004
2. Aug 28, 2004

### humanino

The problem is that it is the color charge that is confined, not the electric charge. Besides, your idea that you can built a light particle such as an electron from quarks seems hopelesly wrong. The $$\pi$$ mesons, which are the lightest strongly interacting particles, already are more than 250 times heavier that the electron ! How could you built anything lighter than a $$\pi$$ meson out of quarks ? You are perfectly right when you indicate that it is the glue that creates the mass. Indeed, you would need to have a different configuration of the glue field, leading to both less energy (mass) content and stronger coupling between the constituents (much stronger). Those two requirements seem to me incompatible.

3. Aug 28, 2004

### kurious

Humanino:

The problem is that it is the color charge that is confined, not the electric charge
Kurious:
But the electric charges of 1/3 and 2/3 are effectively confined too - they cannot exist as independent entities, just as parts of hadrons.

The reason that electrons and positrons do not form analogues to atomic nuclei could be because of gravity.If a strong force carrier is to hold positron-electrons together as mesons keep neutrons and protons together, then the carrier must be able to escape from the electron or positron.A simple Newtonian calculation shows
(v^2 = 2GM/r) that the electron needs a radius of 10^-59 metres in order to stop any force-carrier that bears mass from escaping (I set escape velocity to the speed of light).So an electron with quarks giving it this radius would not show any evidence of a residual colour force.The quarks in the electron would have to be a new generation of light quarks (they would have the configuration -2/3 -2/3 +1/3 - the configuration of an anti-proton, so the electron would be a light version of an antiproton).The colour force would have to be generated by a few gluons that have a higher emission/absorption probability than we would expect for the normal colour force.

Last edited: Aug 28, 2004
4. Aug 28, 2004

### humanino

Indeed. I was noticing that confinement has absolutely nothing to do with watsoever QED. Confinement is a deep problem in QCD. Were the quarks electrically neutral, confinement would be the same.

I am sorry, I keep thinking their is some deep reason failing your model. The radius you quote does not even make sens (cf Planck length).

Here is an objection : you are trying to build a theory far away from any observational possibility, this is not science.

5. Aug 28, 2004

### kurious

Humanino:
Here is an objection : you are trying to build a theory far away from any observational possibility, this is not science.

Kurious:
Then I must bring a quantitative observational possibility into this discussion.
The planck length is not proven to be the shortest length in the universe.
However, there is also the possibility that a quantized gravitational field would
make gravity stronger at a bigger value of the radius.
I'll do a calculation for the energy of a force carrier at a distance
of 10^-59 metres.
A gluon moving at the speed of light would take 10^-67 seconds
to cross 10^-59 metres.
Using E x t = h bar we get E = 10^33 Joules.

This is ridiculous: it amounts to a mass of 10^16 kg per gluon!!

Let's look at the residual colour force.We know from particle accelerators that no reisdual force has been noticed up to 10^-18 metres between positrons and electrons.
Using E x t = hbar we get a force carrier for the postulated residual force, with a mass less than the electron's - 10^-31 kg - with a velocity of 100 metres per second over a distance of 10^-18 metres.The velocity would have to be even slower for a smaller exchange distance between positron and electron.This suggests that a particle that can cause the residual colour force for electrons and positrons is subject to a large force that slows it down and gravity is the most likely cause if the exchange particle is neutral.
What is the magnitude of the maximum force a particle accelerator has put on an electron?This will give us the minimum force holding the quarks in an electron together.Then we can get some idea of the mass of the residual force carrier.

Last edited: Aug 28, 2004
6. Aug 29, 2004

### kurious

If the postulated residual force carrier moves at a maximum of 100 m/s then this is the maximum speed it can impart to a positron or electron.
An electron moving close to the speed of light through a bubble chamber of a particle accelerator experiment would take 10^-7 seconds to cross 10 metres.
It would thus move a maximum distance towards a positron beam moving parallel to its direction of motion of 100 x 10^-7 = 10^-5 metres.
Leptons masses are known to at least 6 decimal places so I would expect
that this size of displacement could be noticed in an accelerator experiment.
Of course, this is a maximum displacement and would be achievable if the force-carrier could transfer all its momentum to an electron in around
10^ -8 seconds.As it would only take the carrier 10^-20 seconds to travel 10^-18 metres at 100m/s this is likely to happen.The real limiting factor in detecting the postulated residual force carrier would be how often the carrier is emitted.If one carrier was emitted every second or so then no residual force would be noticed in an accelerator experiment.Or the effect of the force would be considered to be statistical noise.
A question I would like answered is: if the strong force is mediated by mesons
which are a residual colour force,why are mesons a residual colour force when the colour force is mediated by gluons?

Last edited: Aug 29, 2004
7. Aug 29, 2004

### marlon

Kurious, we don't mind that a certain theory or model is questioned and looked at critically. Yet i think you should try to be more specific, ok ? I mean , don't just give some results, you think are correct, instead give us your whole thinking -process so that we can follow you better. Now this discussion is just very hmmm, eeh, speculative and vague.

How do you come to these results ??? What are the thoughts behind them ???
µWhat do you wanna achieve??? What are your calculations ???

regards
marlon

8. Aug 29, 2004

### kurious

I think I have been specific.However, I will state again what I am trying to do.
There is an asymmetry for electromagnetism from the point of view that the electric charge on electrons can exist independently of other charged particles, whereas the electric charge on quarks only exists in the presence of other electrically charged quarks.The laws of physics are generally symmetrical.An electron made of a new family of quarks would restore symmetry because then no electric charges could truly exist in isolation whether in electrons or in protons and neutrons ( I read somewhere that some GUTs advocate electrons being made from quarks).
Now, the colour force in an electron made from quarks , would be expected to be associated with a strong force for electron-positron interactions.
The mesons that mediate the strong force associated with protons and neutrons have a mass of the same order of magnitude as the neutron and proton masses.
Assuming the same holds true for a strong force mediator for the electron and positron,
then we would expect the strong force mediator for them to have a mass of around
10^-31 kg.In my previous post I have attempted to show that an electron travelling parallel to a beam of positrons and separated from the positrons by 10^-18 m (a distance that has not yet been probed by acclerators), would be attracted to the positrons by the strong force for electron-positrons and this would give the electron a maximum deflection of
10^-5 metres over a distance of 10 metres.But this calculation has not included the electric force between electrons and positrons at 10^-18 metres.

Last edited: Aug 29, 2004
9. Aug 29, 2004

### marlon

The symmetry aspect you are referring to has been made complete by Dirac in the late 40s. He included the existence of the magnetic monopole which has been widely accepted over the years. These monopoles origin from points in the spacetime-manifold where the gauge-transformations are no loger valid, e.g. where singularities occur. But the biggest problem was NOT electrical in nature, it was the fact that there was no dual variant of the electric charged particle. Implementing the Dirac-string (antisymmetrical tensorfield) one can incorporate the existance of magnetic monopoles and taking the covariant derivative of this field yields the magnetic current which is constituted out of them monopoles.

you gotta be careful when you are talking about distance scales because the problems arising from these different scales are already "solved". I mean that the problems (where and where not do we apply perturbation theory ?) they generate are well known.

regards
marlon

10. Aug 29, 2004

### marlon

you are referring to the Quarkconfinement-situation. Yet you are mixing two things : the assymetry in EM does not occur from these fenomena, but from the magnetic monopole as stated in the above post. The properties of quarks is well described via the asymptotical freedom, but this has nothing to do with the assymetry in EM...

regards
marlon

11. Aug 29, 2004

### kurious

marlon:
you are referring to the Quarkconfinement-situation. Yet you are mixing two things : the assymetry in EM does not occur from these fenomena, but from the magnetic monopole

Kurious:
I was aware of Dirac's thinking.
But I am talking about electric charges on the one hand
seeming to be things that can exist on their own (free electrons),
and the other hand being only found in the presence of other electric charges
(in quarks). If a charge of +1 can be caused by confinement of quarks, why can't a charge of -1 be caused by quark confinement?
As I mentioned some GUTs say all particles are made from quarks.
Monopoles have not be found and if too many of them are found
inflation theory will be wrong!

Last edited: Aug 29, 2004
12. Aug 29, 2004

### marlon

You won't see charge -1 because of grouptheory and symmetry. You are mixing two things though. These charges in quarks themselves, which are indeed confined are not just plain electric charges. They are COLOUR electric charges. hence the name colourconfinement.The dual abelian Higgs-model predicts precise values for these colourcharges and a triplet can never yield colourcharge -1

regards
marlon

13. Aug 29, 2004

### kurious

Marlon:
The dual abelian Higgs-model predicts precise values for these colourcharges and a triplet can never yield colourcharge -1

Kurious:

14. Aug 29, 2004

### marlon

Then you are talking about ELECTRIC CHARGE.

It is not because two particles have opposite electric charge, that the colour electric charge is also opposite .

regards
marlon

15. Aug 30, 2004

### chroot

Staff Emeritus
This is also quite clearly too speculative.

- Warren