From: "JACK L. URETSKY (C) 1996; HEP DIV., ARGONNE NATIONAL LAB, ARGONNE, IL 60439" <JLU@hep.anl.gov>
Date: Thu, 13 Mar 1997 12:42:42 -0600 (CST)
Hi all-
Leigh Palmer writes:
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One might make the observation that light has no mass, therefore it
has no electric charge because we have always observed charge is
associated with particles that have mass. Reasoning of that sort
closes the mind to the objective consideration of the properties of
an as yet unobserved phenomenon.
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While I can't disagree with the statement as it stands, I
take exception to the "because we have always observed" part. I
have great difficulty with the concept of a massless charged
particle. That's because, as pointed out in the older E&M texts
(see Heitler, for example) a localized charge has inertia. Thus,
the "classical radius of the electron" is the radius of a sphere
containing the charge on an electron, such that the sphere has
inertia equal to the electron mass.
It is indeed fortunate that the "high temperature vacuum"
of QCD, where all the particles are massless, is broken by the Higgs
mechanism so that at low temperature (or, in "real life") all them
charged guys pick up mass. This fact enables me to live at peace
with the universe (so far).
Regards,
Jack