On the size of isospin violation in low-energy pion - nucleon scattering

Nov, 1998
10 pages
Published in:
  • Phys.Lett.B 451 (1999) 233-240
e-Print:
Report number:
  • FZJ-IKP-TH-1998-29

Citations per year

1999200520112017202201234567
Abstract:
We present an analysis of isospin-breaking effects in threshold pion-nucleon scattering due to the light quark mass difference and the dominant virtual photon effects. We discuss the deviation from various relations, which are exact in the isospin limit. The size of the isospin-violating effects in the relations involving the isovector πN\pi N amplitudes is typically of the order of one percent. We also find a new remarkably large effect (40(\sim 40%) in an isoscalar triangle relation connecting the charged and neutral pion scattering off protons.
Note:
  • 10 pp, LaTeX, uses epsf, 2 figs Report-no: FZJ-IKP(TH)-1998-29
  • pi nucleon: elastic scattering
  • pi nucleon: charge exchange
  • threshold
  • scattering amplitude: isovector
  • scattering amplitude: isoscalar
  • isospin: violation
  • quark: mass difference
  • photon: off-shell
  • Feynman graph: higher-order
  • pi nucleon: scattering length