Is it correct in saying that a particles size is it\'s rest energy, and that par
ID: 1378349 • Letter: I
Question
Is it correct in saying that a particles size is it's rest energy, and that particles don't actually have size (in the way you get different size objects)?
What defines what sizes a particle can be? Why do particles have discrete sizes, and there's not a continuous spectrum of particles varying in size?
I ask because I was told that particles mass depends on its size, as the bigger a particle is the more it interacts with the Higgs boson and so the more mass it has. So why are there so few particles with specific masses/sizes?
Explanation / Answer
The rest energy of a particle determines its mass but not its size.
Although it is often said that elementary particles are points, the correct statement is to say that they are pointlike, because due to renormalization corrections, the point particles that correspond to the bare fields in the defining Lagrangian become slightly extended.
The size of a particle is determined by how the particle responds to scattering experiments, and therefore is (like the size of a ballon) somewhat context-dependent.
My theoretical physics FAQ contains two chapters with several entries related to questions of particle size (and shape, which is related), where much more detail can be found:
Chapter A6: The structure of physical objects
- Does an atom mostly consist of empty space?
- How do atoms and molecules look like?
- When is an object macroscopic?
Chapter B2: Photons and Electrons
- Are electrons pointlike/structureless?
- The shape of photons and electrons
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.