What is the size of elementary particles?

[Vampyr]

"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.

 

[Drakkith]

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.

 

[Bill_K]

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.

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.

 

[Vampyr]

Thank you!