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Full-Text Articles in Physics
Photon-Photon Scattering, Pion Polarizability, And Chiral-Symmetry, Jf Donoghue, Br Holstein
Photon-Photon Scattering, Pion Polarizability, And Chiral-Symmetry, Jf Donoghue, Br Holstein
Physics Department Faculty Publication Series
Recent attempts to detect the pion polarizability via analysis of γγ→ππ measurements are examined. The connection between calculations based on dispersion relations and on chiral perturbation theory is established by matching the low-energy chiral amplitude with that given by a full dispersive treatment. Using the values for the polarizability required by chiral symmetry, predicted and experimental cross sections are shown to be in agreement.
The Equivalence Theorem And Global Anomalies, Jf Donoghue, J Tandean
The Equivalence Theorem And Global Anomalies, Jf Donoghue, J Tandean
Physics Department Faculty Publication Series
In the presence of some forms of global anomalies, the equivalence theorem, which relates the interactions of longitudinal gauge bosons to those of the Goldstone bosons, is not always valid. This can occur when the Goldstone sector gauge an anomaly which is cancelled in the gauge currents by the effects of a different sector of the theory. The example of the standard model without Higgs particles is used to illustrate this phenomena.