Extracting the σ-term from low-energy pion-nucleon scattering

  title={Extracting the $\sigma$-term from low-energy pion-nucleon scattering},
  author={Jacobo Ruiz de Elvira and Martin Hoferichter and Bastian Kubis and Ulf-G. Mei{\ss}ner},
  journal={Journal of Physics G},
We present an extraction of the pion-nucleon (πN) scattering lengths from low-energy πN scattering, by fitting a representation based on Roy–Steiner equations to the low-energy data base. We show that the resulting values confirm the scattering-length determination from pionic atoms, and discuss the stability of the fit results regarding electromagnetic corrections and experimental normalization uncertainties in detail. Our results provide further evidence for a large πN σ-term, σπN = 58(5) MeV… 

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