New Evidence Suggests Electron has a structure!

[Mystery111]

http://www.thenakedscientists.com/HTML/content/interviews/interview/1711/

 

http://www.sciencenews.org/view/feature/id/69229/title/Sizing_up_the_Electron

 

 

Good news for anyone who said mainstream science was wrong in it's contentions about zero dimensionless objects. This evidence suggests that an electron actually does have a classical radius [math]e^2/ Mc^2[/math].

[swansont]

Where's the evidence? Nothing in those links suggest this.

[ajb]

Doesn't the work at Imperial just put better bounds on the electron's electric dipole moment? We know theoretically that this is small, but non-zero due to CP-violation in flavour changing weak processes.

 

I don't see how this suggests the electron necessarily has any internal structure.

Edited September 21, 2011 by ajb

[uncool]

Doesn't the work at Imperial just put better bounds on the electron's electric dipole moment? We know theoretically that this is small, but non-zero due to CP-violation in flavour changing weak processes.

 

I don't see how this suggests the electron necessarily has any internal structure.

Well, that depends on what you mean by internal structure. This would imply that it's not spherically symmetric, which to me would be the definition of having structure - it has a specific direction that it could be considered to be "pointing".

=Uncool-

[ajb]

Well, that depends on what you mean by internal structure. This would imply that it's not spherically symmetric, which to me would be the definition of having structure - it has a specific direction that it could be considered to be "pointing".

=Uncool-

 

But this is all thinking very classically. I am not sure one should interpret the non-zero dipole moment in this way. You calculate the dipole moment within the standard model (you can also do it with SUSY theories and technicolor ) using perturbation theory. You see it is zero until you get to forth loop. It is a very quantum effect!

 

In fact it arises within the standard model due to virtual quarks as these, and not electrons themselves show CP-violation. The small electric dipole moment is very non-classical in origin.

Edited September 21, 2011 by ajb

[uncool]

But this is all thinking very classically. I am not sure one should interpret the non-zero dipole moment in this way. You calculate the dipole moment within the standard model (you can also do it with SUSY theories and technicolor ) using perturbation theory. You see it is zero until you get to forth loop. It is a very quantum effect!

 

In fact it arises within the standard model due to virtual quarks as these, and not electrons themselves show CP-violation. The small electric dipole moment is very non-classical in origin.

In other words, the bare electron has no structure, but the renormalized electron has a dipole moment when chromodynamics is taken into effect, right?

=Uncool-

[ajb]

In other words, the bare electron has no structure, but the renormalized electron has a dipole moment when chromodynamics is taken into effect, right?

 

Sure. The key point is that you need to include the quarks and their CP-violation into the mix. People also look for other CP-violating sectors to include in the mix. The charged Higgs for example could also contribute.

 

 

Anyway, because all this is QFT I would always be careful about interpreting calculations classically.

[uncool]

Sure. The key point is that you need to include the quarks and their CP-violation into the mix. People also look for other CP-violating sectors to include in the mix. The charged Higgs for example could also contribute.

 

 

Anyway, because all this is QFT I would always be careful about interpreting calculations classically.

Well, I don't think I am - I'm just suggesting that the word "structure" as related to particles means that the particle is not spherically symmetric.

 

I'm guessing that you think of it as being a combination of eigenstates of the Hamiltonian, and something without structure is just an eigenstate?

=Uncool-

[ajb]

To me internal structure would mean that the electron would be some bound state of some other particles. One would find excited states in nature, analogous to the hardon spectra. We just don't see these excited electrons and no experiment has produced any evidence for such an internal structure.

[the asinine cretin]

analogous to the hardon ... excited electrons ... no experiment has produced any evidence for such an internal structure.

I was with you until about here. which hardon? does this have something to do with the large hardon collider?

Edited September 21, 2011 by Ceti Alpha V

[swansont]

I was with you until about here. which hardon? does this have something to do with the large hardon collider?

 

Shouldn't that be "whose"?

[the asinine cretin]

Shouldn't that be "whose"?

you tell me. I'm not hip to that kind of physics.

[swansont]

The word is hadron. I was having some fun with the typo.

[Mystery111]

To me internal structure would mean that the electron would be some bound state of some other particles. One would find excited states in nature, analogous to the hardon spectra. We just don't see these excited electrons and no experiment has produced any evidence for such an internal structure.

 

It is possible now (with the recent evidence of the first link) that the electron could really be a classical object - it is a sphere and it might entail the idea of some substructure. The idea should not be beyond physics at all. Glaswegian scientists have even shown that it is possible to explain the electron in terms of a trapped photon following a toroidal knot.

[questionposter]

It is possible now (with the recent evidence of the first link) that the electron could really be a classical object - it is a sphere and it might entail the idea of some substructure. The idea should not be beyond physics at all. Glaswegian scientists have even shown that it is possible to explain the electron in terms of a trapped photon following a toroidal knot.

 

I think that matter is quantized, and electrons/positions are sort of the limit for matter formation in atoms. I mean there's also neutrinos, but those don't have any internal structure either, they are the limits of how small mass-particles can get and after you go past those points one interval, you just reach nothingness or no matter. Even the comparison of electrons being waves is a classical description because the waves we compare them too are only from the classical world, in reality these little particle-waves are their own things.

[the asinine cretin]

The word is hadron. I was having some fun with the typo.

 

yeah, no kidding. so was I obviously.

[ajb]

I was with you until about here. which hardon? does this have something to do with the large hardon collider?

 

You get excited states!

 

Because hadrons are bound states of quarks they have various different energy configurations. Thus we have a who spectra of particles that we can observe that have almost identical properties apart from mass.

 

If the electron has some similar sub structure you would expect something similar. The muon and tau do not appear to be simple excited states of the electron. These "higher mass electrons" are also fundamental rather than composites.

 

It is possible now (with the recent evidence of the first link) that the electron could really be a classical object - it is a sphere and it might entail the idea of some substructure. The idea should not be beyond physics at all.

 

I just don't think you can read it that way. What the scientists have done is use a classical analogy to simply state what they are looking for. It is a great picture and gives some intuitive feel. One interprets no electric dipole as the electron as being "classical spherical" and any non-zero electric dipole measures this deviation from "classically spherical". I like what they have said, but they are popularising their work and this will always require some analogy and "common sense" thinking. Nature on the atomic and smaller scales is just not classical like that.

 

In reality they are probing CP-violation and I am sure they know that. It is a great result and suggests that our theories are good, especially the standard model. In particular their results are consistent with out theoretical understanding. Of course it would have been exciting if they got some large value for the dipole moment that just does not fit with the standard model!

 

Getting good bounds on the electron electric dipole moment is important for supersymmetry, technicolor and other theories beyond the standard model. It represents one place to attempt to rule out certain theories.

[the asinine cretin]

You get excited states!

 

Because hadrons are bound states of quarks they have various different energy configurations. Thus we have a who spectra of particles that we can observe that have almost identical properties apart from mass.

 

If the electron has some similar sub structure you would expect something similar. The muon and tau do not appear to be simple excited states of the electron. These "higher mass electrons" are also fundamental rather than composites.

 

[swansont]

You get excited states!

 

And pickup lines like "Do you want to measure my Cabibbo angle?"

[Mystery111]

I just don't think you can read it that way.

 

 

I don't think you can say it doesn't imply what I said.

 

 

Pointlike particles have no structure - it cannot be described as a sphere. Before the release of the information in the OP, we must have treated the electron; an object which has no structure, pointlike, dimensionless.

 

Now we can prove that wrong. evidence suggests the electron does have a structure after all and thus can be described by a classical radius, which is simply a line seperating the radius of curvature, or the Compton Wavelength from it's center.

 

How more classical can you get? And why would it not mean what I've said? I think it's all very clear.

 

(I was naturally buzzed when I read the article in the OP. I had been saying the electron, indeed all particles must have a structure for while.)

Edited September 26, 2011 by Mystery111

[ajb]

The classical electron radius is the size an electron would have to be in order for the mass to be completely due to its electrostatic potential energy. One does not think of the classical electron radius as the actual size of the electron. It is really the scale at which quantum effects, and in particular QED renormalisation effects need to be taken care of. The formula for the classical electron radius involves Planck's constant, meaning it is really a quantum thing. Just as important it contains the electrons Compton wave length and this tells us that QED should really come into play.

 

 

This is all quite far from thinking of the electron as a tiny billiard ball.

[Mystery111]

Either way ajb, we could be technical to every point. But I saw people arguing my interpretation of their work does not imply what I said, but to be honest, you cannot have both a pointlike particle and something which has a sphere! The two identities are totally different with the latter containing dimension.

 

So my interpretation cannot surely be argued with. If their experimentation is correct, then the electron must have a structure, call it the classical radius, or simply a radius. The size of an electron matters not much, so long as we remember it is not as small enough to say it doesn't even have a body-structure!

[ajb]

So my interpretation cannot surely be argued with.

 

As a tiny, not quite perfectly spherical billiard ball?

[Mystery111]

As a non-zero dimensional particle.

Edited September 26, 2011 by Mystery111

[swansont]

Either way ajb, we could be technical to every point. But I saw people arguing my interpretation of their work does not imply what I said, but to be honest, you cannot have both a pointlike particle and something which has a sphere! The two identities are totally different with the latter containing dimension.

 

So my interpretation cannot surely be argued with. If their experimentation is correct, then the electron must have a structure, call it the classical radius, or simply a radius. The size of an electron matters not much, so long as we remember it is not as small enough to say it doesn't even have a body-structure!

 

Their experimentation found no EDM. The experiments set the limit at 10^-29 e-cm. The "electron is a sphere" description is the journalist trying to translate the physics into a readable article. They're measuring the spherical symmetry of the electric field, not the electron itself.