57,521 research outputs found
The technique of inverse Mellin transform for processes occurring in a background magnetic field
We develop the technique of inverse Mellin transform for processes occurring
in a background magnetic field. We show by analyticity that the energy
(momentum) derivatives of a field theory amplitude at the zero energy
(momentum) is equal to the Mellin transform of the absorptive part of the
amplitude. By inverting the transform, the absorptive part of the amplitude can
be easily calculated. We apply this technique to calculate the photon
polarization function in a background magnetic field.Comment: 3 pages, LATEX; talk presented at ICHEP02, Amsterdam, The
Netherlands, 24-31 July 200
Generalizing the Coleman-Hill Theorem
Following the work of Khare {\it et al}, we show that the generalization to
systems with spontaneous symmetry breaking of the Coleman-Hill theorem to
one-loop order, can be extended to the case including fermions with the most
general interactions. Although the correction to the parity-odd part of the
vacuum polarization looks complicated in the Higgs phase, it turns out that the
correction to the Chern-Simons term is identical to that in the symmetric
phase, with the difference coming only from the contribution of the would be
Chern-Simons term. We also discuss the implication of our result to nonabelian
systems.Comment: 11 pages, uses phyzzx. Abstract and conclusion modified, new
reference adde
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