Linked Questions

61 votes
7 answers

Do electrons have shape?

According to the Wikipedia page on the electron: The electron has no known substructure. Hence, it is defined or assumed to be a point particle with a point charge and no spatial extent. Does ...
Anil Bharadia's user avatar
50 votes
4 answers

What is the mass density distribution of an electron?

I am wondering if the mass density profile $\rho(\vec{r})$ has been characterized for atomic particles such as quarks and electrons. I am currently taking an intro class in quantum mechanics, and I ...
clevy's user avatar
  • 603
32 votes
6 answers

Where is the evidence that the electron is pointlike?

I'm writing a piece about the electron, and I'm having trouble finding evidence to back up the claim that the evidence is pointlike. People tend to say the observation of a single electron in a ...
John Duffield's user avatar
32 votes
2 answers

The concept of particle in QFT

I never learnt QFT and I apologize for my (probably) elementary question. Somebody told me that in QFT a particle is viewed as an irregularity in the field. On the other hand, in an article in ...
Sofia's user avatar
  • 6,726
21 votes
7 answers

Why do physicists believe that particles are pointlike?

String theory gives physicists reason to believe that particles are 1-dimensional strings because the theory has a purpose - unifying gravity with the gauge theories. So why is it that it's popular ...
Olly Price's user avatar
24 votes
3 answers

What are the dimensions, width and length, of a photon?

Everyone is always talking about photon's wavelength. But what about its dimensions? What is length and width of it? And does it even have a point to think about such things? Or those dimensions are ...
user46147's user avatar
  • 2,906
11 votes
4 answers

Have fundamental particles been observed?

Addendum: the answer appears to be either "no" or "depends on what you mean". Most of the "depends" involve a meaning of "particle" that is clearly jargon. My ...
Ponder Stibbons's user avatar
4 votes
2 answers

Volume of a Photon?

I understand that photons, like the other elementary particles, is a point particle and doesn't technically have definite boundaries. However, protons and other baryonic matter have a mean atomic ...
A. Forty's user avatar
  • 173
4 votes
2 answers

Heisenberg uncertainty principle and particle physics

Studying the QCD running coupling constant I ran into this figure: where $Q$ on the $x$ axis represents the transferred momentum. I know from a Nuclear and Subnuclear Physics course that the strong ...
Luthien's user avatar
  • 1,482
8 votes
1 answer

In less technical language, what exactly is a "gravitational form factor"?

The term "gravitational form factor" is a term I don't recall ever seeing before the year 2018 (about three decades after I started reading physics papers). I have read several recent papers about ...
ohwilleke's user avatar
  • 3,823
0 votes
0 answers

Roundness of electrons [duplicate]

I have seen articles online discussing the roundness of electrons. This goes a bit against my understanding of electrons as elementary point like particles. How can a point have a shape? What does ...
Tjommen's user avatar
  • 191