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Re: subatomic scales



Maurice,
You failed to point out that this classical size is about the
size of the nucleus if not bigger. Rule of thumb is that the radius of
a nucleus is 1.2fm * A^(1/3), where A is the atomic mass of the nucleus
in question (or total number of nucleons - protons and neutrons). So
for a Hydorgen atom (proton), the electron is more than twice as big as
it.
To me, this gives strong evidence that the electron is a delta
function of charge (an infinitely thin collection of charge).


-----Original Message-----
From: Maurice Barnhill [mailto:mvb@UDEL.EDU]
Sent: Friday, November 13, 1998 3:55 PM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: subatomic scales


The classical radius of the electron is e^2/(4 pi epsilon-0 m c^2) which
is 2.8 x 10^(-15) m. It is a bit artificial, since it is the radius the
electron would have to be if it were uniformly charged and its rest mass
was given by its electrostatic energy divided by c^2. No experiment has
detected any internal charge or mass distribution for either the
electron or for any quark, so both have "radii" below the level that
would be detectable experimentally.

Zach Wolff wrote:

What is the order of magnitude of the classical radius of the elecron?
Is there any value for the radius of a quark?

Zach

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--
Maurice Barnhill, mvb@udel.edu
http://www.physics.udel.edu/~barnhill/
Physics Dept., University of Delaware, Newark, DE 19716