Do Electrons Have a Non-Zero Radius or Are They Truly Point-Like?

[kurious]

Electrons are usually considered to be point-like particles but are there any
theories that say they have a non-zero radius?

 

[mathman]

There is something called the classical radius, which is defined as e²/mc², and is numerically 2.81777x10^-13 cm. In the definition e=electron charge, m=mass, and c= speed of light.

 

[kichigai]

Electrons are usually considered to be point-like particles but are there any
theories that say they have a non-zero radius?

There's a Kluwer Publishing book called: "The Enigmatic Electron" by Malcolm MacGregor who used to work for Lawrence Livermore National Labs that has a lot of info on the electron.

 

[quasar987]

The book costs 158$ at amazon.com ! What's in it that's so expansive?

 

[kichigai]

The book costs 158$ at amazon.com ! What's in it that's so expansive?

Not sure how to add an attachment yet, so here's part of the TOC.

Preface: The rationale for the present book

Part I. The Crisis: Classical vis a vis Quantum Physics
Chapter 1. Three unanswered questions in twentieth century physics
A. What is the size of the electron
B. What is the nature of the electron mass
C. Are there experiments that reveal the size of the electron
D. The 1990 Antigonish electron workshop
Chapter 2. Some new ideas in an old field of physics
Chapter 3. The breakdown of classical physics in the electron
A. Conflicts wiht classical EM
B. Conflicts with SR
Chapter 4. A possible reunion of classical and quantum physics

Part II. The natural size of the electron
Chapter 5. The natural size of an elementary particle
Chapter 6. The spectroscopic and bulk sizes of the electron
A. The spectroscopic size of the electron
B. Bulk measurements of particle sizes
Chapter 7. The electric sizes and electric self-energy of the electron
Chapter 8. The magnetic size, magnetic self-energy and anomalous magnetic moment of the electron

Part III. The Spectroscopic Electron
Chapter 9. Do we need a spectroscopic model of the electron
Chapter 10. Spin quantization and the relativistically spinning sphere
Chapter 11. A classical spectroscopic model of the electron
Chapter 12. The Lorentz invariance of a finiste-sized electron
Chapter 13. Spatial quanitization and the two-component rotation group
Chapter 14. A quantum-mechanical model of the electron

Part IV. The Mott channeling of finite-sized electrons
Chapter 15. Mechanical mass: a new state of matter
Chapter 16. The keV Mott helical-channeling window
Chapter 17. Experimental evidence for helical channeling

And some appendices on experiments.

Hope that helps.

 

[what_are_electrons]

Electrons are usually considered to be point-like particles but are there any
theories that say they have a non-zero radius?

The book titled "The Enigmatic Electron" provides these values:

1. R(E) (point-like charge radius)-------------------<1 x 10-16 cm
2. R(0) (classical radius)--------------------------2.82 x 10-13 cm
3. R(C) (Compton sized electron)------------------3.86 x 10-11 cm
4. R(E) Effective (R(E) = 2/5 RC)-------------------1.5 x 10-11 cm
5. R(E) Effective - Corr (R(E) = XX R(C)-------------1.3 x 10-11 cm
6. R(H) (based on Compton radius)--------------------4 x 10-12 cm
7. R(H) (based on classical radius) -----------------4.09 x 10-12 cm
8. R(H) QM-Corrected (R(H) = (sqrt of 3)*R(C))----6.69 x 10-11 cm
9. Scattering results before 1992 imply--------------< 1 x 10-16 cm
10. Scattering results very recently imply------------< 1 x 10-18 cm

As state in this boo, the electron experts are currently debating whether or not electrons have a true mechanical mass at the center of the electron which would be much smaller than any electrical charge based radius. There is no direct discussion of the magnetic radius size, but there are a few hints at it.

 

[kurious]

Thanks a lot folks.