Does an electron have an internal structure?

[malawi_glenn]

JustinLevy: pick up a textbook on quantum angular momenta. I think Edmonds is the best which I have tried. Quantum angular momentum is very well understood mathematically.

No spectrum has been obtained for the electron eiether, or anyone else of the leptons.

Of course I cannot disprove substructure of electron from experiment, but with todays limit, and the sucess of the Standard Model and rules of quantum angular momenta and the absence of excitation spectras also of the muon and the tau - makes a decomposition of the electron into smaller point-lime particles extremely hard to believe. There is not even a single sign of the electron or any other lepton to have such substructure. But you cannot, as you say, 100% rule things out.

So it was not a "proof" I gave you in "If the electron has substructure, it can not have substructure of the kind "point particles" described by todays physics. It must be something else, like strings." - it was my summary of what I believe is the current status of elementary particle physics.

Also imagine what these new substructure particles of the electron would cause? - well a new force, new particles etc. In general, this is not what physicists wants, but physicsists wants to describe and discover how nature is, so it is always a dilemma...

granpa has a temporary banning I was told

 

[per.sundqvist]

What!?
Are you thinking of right handed vs. left handed electrons?
If so, it does not mean that the electron has "two spin structures are spining at 90 degrees to each other".

Regardless, this sounds more like a personal theory of yours instead of something that can be traced to Dirac, for this is highly unconventional. I agree with ZapperZ, please cite a source that lead you to believe this.


I would have to disagree here. This argument does not allow you to rule out preon models (otherwise, indeed, all preon models would have been ruled out long ago).

The problem is that you assumed the particles are non-interacting in your calculation. If the effective potential is very negative within the bound state, the total energy and kinetic energy due to "confinement" can still work out fine.


You've mentioned something similar before as well. Where are you getting this idea that spin is determined by e/m? If it were, since spin comes in quantized units, and charge comes in quantized units, so too would m. This is obviously not the case.

I was not ignoring interaction, just assumed that the effective potential for one sup-particle (like the one you get from a Hartree model) was like a potential well. It is in fact (E-V)/2m0c^2 that makes the relativistic correction, so if you shift V down in case of some negative attractive potential, it should not matter to much.

We have of course no idea about what force that could bind together the leptonic sub-particles, so an effective hard-wall potential is fair enough. Anyway it can be shown that if you add a strong confining potential (like parabolic) to a Coulomb attraction potential, the eigenstate becomes more and more dependent only of the parabolic potential. Veff=-A/r+k*r^2, where ka^2>>A/a, where a is a typical distance from scaling theory. I had something like this in mind when I thought of the effective constant potential.

 

[per.sundqvist]

You are assuming much more.
-Your assuming the structure is a particle structure rather than some other structure (e.g. string like/type).
-Your assuming that the experimental point like radius (<10^18 m) is the size rather than the resultant effective size (e.g. gyroscopic objects react about the center point dispite the extent)

The mathematics (dirac spinor) and experiment actually suggest that there are two spin structures (the electron is mistakenly picture as having only a spin up and spin down state, but in actuallity the mathematics indicates four spin orientations). These two spin structures are spining at 90 degrees to each other (physically 90 degree orthagonal vs spinor mathematical 180 degree orthagonal).

Note that with two 90 degree spin sturctures (magnetic quadrupole) things like the stern-gerlach experiment now makes physical sense. The first magnetic field only orients one of the two orthagonal magnetic spins (up or down, 50/50 probability) with a while the second spin plane in unoriented. A second stern gerlach magnet field at 90 degrees to the first thus also result in a 50/50 probability of spin up or down because it is orientated to this second unoriented spin plane.

This thought experiment is not proof of structure, but...?

What is this argument about two magnetic fields? The first and the second? To my knowledge B=B1+B2 holds well, why the new vector B-field is only reoriented in another direction and this will NOT cause any mystic effect in the Stern-Gerlach experiment!

 

[per.sundqvist]

The mathematics (dirac spinor) and experiment actually suggest that there are two spin structures (the electron is mistakenly picture as having only a spin up and spin down state, but in actuallity the mathematics indicates four spin orientations). These two spin structures are spining at 90 degrees to each other (physically 90 degree orthagonal vs spinor mathematical 180 degree orthagonal).

Hmm, do you talk about the two lower spinors here? In the time-independent solution all physics is obtained exactly by the two upper (space-like, Phi) and the lower two (momentum-like, Chi) spinors are always given in terms of the upper ones

<br /> \chi &amp;=&amp;<br /> \frac{\kappa(\vec{r})}{2m_0c}\left(-i\hbar\nabla-e\vec{A}\right)\cdot\tilde{\vec{\sigma}}\phi,<br />
<br /> \kappa(\vec{r}) &amp;=&amp; \frac{1}{1+\frac{E-V(\vec{r})}{2m_0c^2}},<br />

Parhaps I missunderstood the B-field as well. Maby you was talking about an arrangement like in the first pages of Sakurai, with the discussion of spin polarization? In that case the four spinor (the lower two "chi") has nothing to do with it.

Also, a satisfactory many-particle Dirac equation has not yet been presented, to really understand the meaning of "spinor" in that case (some presented models gives unphysical and singular solutions). Have tried to formulate this by my self a time ago but got stuck because of to many degrees of freedom. The thing I use now is to set up the spinor with 2^n elements like in a binary table (n=number of electrons). (up-down, up-up,... etc for two electrons).

 

[enotstrebor]

Can you please provide citations where these have been published? And how would you reconcile this with all our observations of spin-triple and spin-singlet pairings, not to mention, results from every single electron paramagnetic resonance experiments?

Zz.

I thought that the ``Dirac electron'' (spin 1/2 particle) was mathematically a 720 degree particle requiring four spin flips (a spin flip is orthogonal but mathematically is 180 degree) was common knowledge (SEE http://en.wikipedia.org/wiki/Spin-%C2%BD" subtopic ``SYMMETRY'')

The (four) spinor also has positive and negative helicities. (See R. Penrose, {\it ``The Road to Reality'' and associated zigzag picture of electron},

As this mathematical aspect gives the correct results, one might suggest that it reflects the true physics but to be physical physics the orthogonality would be two (one positive and one negative helicity) spin planes at 90 degrees.

As indicated this physical view of the mathematics makes the Stern-Gerlach experimental results physically sensible.

And how would you reconcile this with all our observations of spin-triple and spin-singlet pairings,...?
Zz.

The zero spin state has both spin axes alighned the other triplet has one aligned and one anti-aligned. One can not have a stable state where both are anti-aligned.

..., not to mention, results from every single electron paramagnetic resonance experiments?
Zz.

Flipping between the two orthogonal spin states is what the mathematics says. This has been given the mathimatical picture of spin up and down which are mathmatically 180 degree orthagonal. The only thing that changes is that the physical picture is physically orthagonal and the spin flip is from one of the two spin planes to the other orthogonal spin planes.

(Note that according to the mathematics a 360 degree rotation is a change in phase not a 180 degree flip. The electron flips 180 degrees from a spin up (right helicity arrow up) to a spin down (left helicity arrow up) then flips a second 180 degrees to change phase, i.e spin up (right helicity arrow down), then flips a third 180 degrees (same phase), i.e spin down (left helicity arrow down), then flips a fourth time to return to the same state. i.e. spin up (right helicity arrow up)

And how would you reconcile this
Zz.

This dual spin picture of the electron is in keeping with all experimental evidence that I am aware of and in keeping with the mathematics.

It simply a new picture and it makes all experiments sensible.