Analysis of the Low-Energy Theorem for γp \to p π^0

Abstract

The derivation of the `classical' low-energy theorem (LET) for γp \rightarrow pπ^0 is re-examined and compared to chiral perturbation theory. Both results are correct and are not contradictory; they differ because different expansions of the same quantity are involved. Possible modifications of the extended partially conserved axial-vector current relation, one of the starting points in the derivation of the LET, are discussed. An alternate, more transparent form of the LET is presented.

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