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The reactions $pp\to ppπ^0$ and $pp\to dπ^+$ at threshold: The role of the isoscalar $πN$ scattering amplitude

C. Hanhart·J. Haidenbauer·M. Hoffmann·Ulf-G. Meißner·J. Speth
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Abstract

We examine the role of the elementary isoscalar pion--nucleon scattering amplitude in the description of the processes $pp \to ppπ^0$ and $pp\to dπ^+$ at threshold. We argue that the presently used tree level dimension two approximation used in chiral perturbation theory is insufficient as input by direct comparison with the $π$N scattering data. We also show that a successful semi--phenomenological boson--exchange model does better in the description of these data. The influence of the violation of crossing symmetry in the meson--exchange model has to be studied in more detail. We stress that further investigations of the process $pp\to dπ^+$ can pave the way to a deeper understanding of the pion dominated part of the transition operator.

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C. Hanhart, J. Haidenbauer, M. Hoffmann, Ulf-G. Meißner, J. Speth. 1998-04-28. The reactions $pp\to ppπ^0$ and $pp\to dπ^+$ at threshold: The role of the isoscalar $πN$ scattering amplitude. https://doi.org/10.1016/s0370-2693(98)00216-0

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