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arXiv · hep-ph/9908249

Nothing anomalous about two-loop HBCPT: consistency with the LET for spin-dependent Compton scattering

Judith A. McGovern·Michael C. Birse
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Abstract

The leading order contributions of processes involving anomalous pion-photon vertices to forward spin-dependent Compton scattering from nucleons are considered in heavy-baryon chiral perturbation theory. These all involve the exchange of three pions between one or two photons and the nucleon, and hence are two-loop processes. We find that the sum of these processes vanishes in the manner predicted by the low energy theorem of Low, Gell-Mann and Goldberger as the photon energy goes to zero. This provides the first consistency test of two-loop HBCPT.

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Judith A. McGovern, Michael C. Birse. 1999-12-23. Nothing anomalous about two-loop HBCPT: consistency with the LET for spin-dependent Compton scattering. https://doi.org/10.1103/physrevd.61.017503

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