Re: anomalous magnetic dipole moment vs CPT

[Joseph Warner]

"katastrofa_nadfioletu" <katastrofa.nadfioletu@gmail.com> wrote
in message
news:5808f688-a2f3-46f1-8b36-564cdb8bb17e@p25g2000hsf.googlegroups.com...
> Hello Group,
> it is known that the anomalous electric dipole moment is
> violating P-
> symmetry. I wonder whether adding the term describing Pauli
> interaction of anomalous magnetic dipole moment with
> electromagnetic
> field to the Dirac's lagrangean density violates any of C, P
> or T -
> symmetries? (Of course I remember that it should be CPT
> invariant, so
> if it violates any, it necessarily violates two of them :))

I believe that anomalous magnetic dipole moment violates T.

Joe Warner

[katastrofa_nadfioletu]

On May 30, 1:01 am, Joseph Warner <Joseph.D.War...@nasa.gov> wrote:

>
> I believe that anomalous magnetic dipole moment violates T.
>

Hmmm, but how should I understand you "believe"? Do you mean that we
should seek for a mathematical formula describing interaction of this
(hyphothetical but still possible) physical feature of a particle with
E-M filed that would have this (P-violating) property? (If yes -
why???) Because the term proposed by Pauli, which I've used in the
above calculations, doesn't violate any of them. I've risen that
question as I wasn't sure whether I've made mistake or not.
with regards
m

[Joseph Warner]

"katastrofa_nadfioletu" <katastrofa.nadfioletu@gmail.com> wrote
in message
news:e00d7794-84c6-45c2-b33e-5d6598f09d17@t54g2000hsg.googlegroups.com...
> On May 30, 1:01 am, Joseph Warner <Joseph.D.War...@nasa.gov>
> wrote:
>
>>
>> I believe that anomalous magnetic dipole moment violates T.
>>
>
> Hmmm, but how should I understand you "believe"? Do you mean
> that we
> should seek for a mathematical formula describing interaction
> of this
> (hyphothetical but still possible) physical feature of a
> particle with
> E-M filed that would have this (P-violating) property? (If
> yes -
> why???) Because the term proposed by Pauli, which I've used in
> the
> above calculations, doesn't violate any of them. I've risen
> that
> question as I wasn't sure whether I've made mistake or not.
> with regards
> m
>

This isn't too hard to see. Take a uniform magnetic field and a
charge particle. Let the particle's velocity be perpendicular to
the magnetic field, use the right hand rule to see the direction
of the deflection. Have the particle deflect until its velocity
in perpendicular to its original velocity. Now reverse its
velocity without changing its charge. You will see it does not
follow the same path. To make it follow the same path the charge
has to be reversed along with the velocity.

[katastrofa_nadfioletu]

On 2 Cze, 17:07, Joseph Warner <Joseph.D.War...@nasa.gov> wrote:
>
> This isn't too hard to see. Take a uniform magnetic field and a
> charge particle. Let the particle's velocity be perpendicular to
> the magnetic field, use the right hand rule to see the direction
> of the deflection. Have the particle deflect until its velocity
> in perpendicular to its original velocity. Now reverse its
> velocity without changing its charge. You will see it does not
> follow the same path. To make it follow the same path the charge
> has to be reversed along with the velocity.

What you are describing is not the time reversal transformation of a
system consisting of a charged particle in a magnetic field... You've
forgotten that the magnetic field is desrcibed by the curl of vector
potential. The latter, however, chages its sign when you reverse the
time. (e.g. classically, it can be produced by some electric current.
which changes direction under this transformation).

Coming back to the anomalous magnetic dipole moment: for an electron
it is a small correction to the "ordinary" magnetic moment, but e.g.
proton has relatively large anomalous magnetic dipole moment (which
means that observed magnetic moment of proton differs from the one
calculated via gyromagnetic ratio). The most important, however, is
the fact that neutron also interacts with E-M field, so one can say
(at last I understand it in this way) its magnetic moment is all an
"anomalous one".