Eur. Phys. J. A (2007) 32: 321-325
https://doi.org/10.1140/epja/i2007-10377-6

Regular Article - Hadron Physics

The Goldberger-Miyazawa-Oehme sum rule revisited

¹ Petersburg Nuclear Physics Institute, 188300, Gatchina, Russia
² Department of Physical Sciences, University of Helsinki, P.O. Box 64, 00014, Finland
³ Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, 00014, Finland

Received: 23 April 2007
Accepted: 15 May 2007
Published online: 25 May 2007

Abstract

The Goldberger-Miyazawa-Oehme sum rule is used to extract the pion-nucleon coupling constant from experimental π N information. Chiral perturbation theory is exploited in relating the pionic hydrogen s -wave level shift and width results to the appropriate scattering lengths. The deduced value for the coupling is f ² = 0.075±0.002 , where the largest source of uncertainty is the determination of the s -wave π^- p scattering length from the atomic level shift measurement.