Re: Question About Charged Particles.

[Jack Uretsky <jlu@HEP.ANL.GOV>]

        I do not wish to be listened to as though I am some sort of a
"guru" uttering "truths".  As far as I am concerned, the "voice of
authority" has no place in the study of physics.
        My point is that Zanelli's question can be answered either way,
depending on what model one relies upon.  Said otherwise, to the extent
that the question implies a model (as it did in one version), then that
model provides an answer.
        John Denker chooses classical physics as his model. That model
gives a different answer than QED.  In QCD we have the peculiar
circumstance (in the confining phase) that the constituents cannot appear
as asymptotic states, so the usual tools of quantum field theory seem
not seem to make sense.
        John's argument is also troublesome.  If a particle is massless,
it must be moving with the speed of light.  I don't know how to turn on a
charge on such an object.  He argues in terms of the field that accompanies a
charged object in its rest frame.  But once he assumes a rest frame he
has already implied that the object is massive.
        CAVEAT:  I never said that the question is trivial - I said that
it strikes me as a non-question because the answer depends upon the model
that one chooses.
                                Regards,
                                        Jack

On Sat, 7 Apr 2001, Robert B Zannelli wrote:

> In a message dated 4/7/01 9:08:08 PM Eastern Daylight Time, jlu@HEP.ANL.GOV
> writes:
>
>
>  A clarification.
>
> Jack Utetsky writes
>
> I have already suggested.  If I calculate the corrections to the mass (as
>  in QED), I find that the corrections are proportional to the bare mass.
>  If I believe that these corrections are governed by a cut-off, as the
>  modern philosophy goes, then massless particles remain massless after
>  taking into account the effect of their EM field.>>
>
> This conclusion was not reached on the other list.  It was believed that a
> massless particle with an electric charge was not possible.
>
> Jack writes:
>
>          So I can clearly have theories in which charged particles are
>  massless.  It is my guess that consistent theories would require such
>  particles to be confined (like gluons, which have color charge), but we
>  seem to be a long way from proving such a guess.>>
>
> However I don't believe massless charged particle were ruled out if they was
> confined. Personally I suspect your answer is the most correct given these
> two opinions. I believe John Denker also held out the possibility of a
> massless charged particle being possible.
>
> Bob Zannelli

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