Linked Questions
10 questions linked to/from What is the meaning of the size of a particle in QFT?
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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 ...
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7
answers
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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 ...
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21
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7
answers
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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 ...
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34
votes
6
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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 ...
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52
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4
answers
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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 ...
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11
votes
4
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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 ...
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33
votes
2
answers
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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 ...
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5
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2
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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 ...
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4
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2
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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 ...
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9
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1
answer
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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 ...
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