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A next-to-next-to-leading-order $pp \to ppπ^0$ transition operator in chiral perturbation theory

V. Dmitrašinović·K. Kubodera·F. Myhrer·T. Sato
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Abstract

We present a systematic analysis of next-to-next-to-leading-order diagrams that contribute to the $pp \to ppπ^0$ production at threshold. Analytic expressions are given for the effective transition operators, and the relative importance of various types of diagrams is discussed. The vertex-correction-type graphs are found to give only small corrections to lower order graphs in conformity with expectations. By contrast, we find very large contributions from the two-pion graphs which can be interpreted as a part of effective $σ$-meson exchange diagrams. The recoil correction to the pion rescattering diagram also turns out to be large.

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V. Dmitrašinović, K. Kubodera, F. Myhrer, T. Sato. 1999-09-23. A next-to-next-to-leading-order $pp \to ppπ^0$ transition operator in chiral perturbation theory. https://doi.org/10.1016/s0370-2693(99)01075-8

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