Determination of the real part of the isospin-even forward-scattering amplitude of pion-nucleon scattering at 55 MeV as a test of low-energy quantum chromodynamics
Wiedner, U.; Goering, K.; Jaki, J.; Klein, U.; Kluge, W.; Matthaey, H.; Metzler, M.; Pedroni, E.; Fetscher, W.; Gerber, H. J.; Koch, R.