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arXiv · hep-ph/9908247

Pion-nucleon scattering inside the Mandelstam triangle

Paul Büttiker·Ulf-G. Meißner
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Abstract

We study the third order pion-nucleon scattering amplitude obtained from heavy baryon chiral perturbation theory inside the Mandelstam triangle. We reconstruct the pion-nucleon amplitude in the unphysical region by use of dispersion relations and determine the pertinent low-energy constants by a fit to this amplitude. A detailed comparison with values obtained from phase shift analysis is given. Our analysis leads to a pion-nucleon sigma-term of sigma(0) = 40 MeV based on the Karlsruhe partial wave analysis. We have repeated the same procedure using the latest solution of the VPI group and find a much larger value for sigma(0).

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Paul Büttiker, Ulf-G. Meißner. 1999-08-04. Pion-nucleon scattering inside the Mandelstam triangle. https://doi.org/10.1016/s0375-9474(99)00813-1

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