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Size of elemetary particles

  1. Aug 21, 2013 #1
    "Size" of elemetary particles

    I stumbled upon this nice link showing the universe at different scales: http://htwins.net/scale2/

    However, if you scroll down to the attometer scale you get to the elementary particles which have been given sizes. Does anyone know what these sizes mean? I thought elementary particles were dimensionless and so have no strict size.
  2. jcsd
  3. Aug 21, 2013 #2


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    Staff: Mentor

    I'd guess it either refers to something similar to a "classical electron radius" or it uses their wavefunction to determine the volume of space they are likely to occupy and base the size on that.
  4. Aug 21, 2013 #3


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    Science Advisor

    You're correct. Apparently what he's diagramming here is the Compton wavelength for each particle, ħ/mc. Of the six quarks, the top quark has the greatest rest mass, hence the shortest Compton wavelength. Electron (classical) is the classical electron radius, e2/mc2.
  5. Aug 21, 2013 #4
    Thank you!
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