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Dispersive analysis of the scalar form factor of the nucleon

  • M. HoferichterEmail author
  • C. Ditsche
  • B. Kubis
  • U.-G. Meißner
Article

Abstract

Based on the recently proposed Roy-Steiner equations for pion-nucleon (πN) scattering [1], we derive a system of coupled integral equations for the \( \pi \pi \to \overline N N \) and \( \overline K K \to \overline N N \) S-waves. These equations take the form of a two-channel Muskhelishvili-Omnès problem, whose solution in the presence of a finite matching point is discussed. We use these results to update the dispersive analysis of the scalar form factor of the nucleon fully including \( \overline K K \) intermediate states. In particular, we determine the correction \( {\Delta_{\sigma }} = \sigma \left( {2M_{\pi }^2} \right) - {\sigma_{{\pi N}}} \), which is needed for the extraction of the pion-nucleon σ term from πN scattering, as a function of pion-nucleon subthreshold parameters and the πN coupling constant.

Keywords

Chiral Lagrangians QCD 

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Copyright information

© SISSA, Trieste, Italy 2012

Authors and Affiliations

  • M. Hoferichter
    • 1
    Email author
  • C. Ditsche
    • 1
  • B. Kubis
    • 1
  • U.-G. Meißner
    • 1
    • 2
  1. 1.Helmholtz–Institut für Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universität BonnBonnGermany
  2. 2.Institut für Kernphysik, Institute for Advanced Simulation and Jülich Center for Hadron Physics, Forschungszentrum JülichJülichGermany

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