Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

THE COMPLEX DIAGRAM OF THE PION-NUCLEON FORWARD SCATTERING AMPLITUDE

Journal Article · · Nuclear Physics (Netherlands) Divided into Nucl. Phys. A and Nucl. Phys. B
OSTI ID:4126226
The pion-nucleon forward scattering amplitude F/sub b/ was calculated from dispersion relations and the optical theorem, using new data of the total cross sections. The results are given as diagrams that show the energy dependence of the complex vectors qF/sub b/ (q = pion momentum), the contribution of an elastic resonance being a circle in this representation. The pion-nucleon resonances and the non-resonant part of the scattering are discussed by the use of the diagrams for isospin 3/2,1/2 and the charge exchange scattering amplitude. Near 900 Mev the curve for isospin 1/2 has a shape similar to that belonging to the first resonance and suggests an almost elastic J = 5/2 state for the third resonance. At the other maxima of the total cross sections the behavior is compatible with the existence of resonances, but there is no indication for a T =3/2 resonance at the shoulder of the total pi /sup +/p cross section near 875 Mev. In the region of the third resonance the non-resonant part cannot be described by a simple diffraction model. It is pointed out that the diagrams of the forward amplitude are useful as a meeting place of theory and experiment, being more easily accessible than the phase shifts from the side of the experiments. (auth)
Research Organization:
Technische Hochschule Karlsruhe, Ger.
NSA Number:
NSA-18-006009
OSTI ID:
4126226
Journal Information:
Nuclear Physics (Netherlands) Divided into Nucl. Phys. A and Nucl. Phys. B, Journal Name: Nuclear Physics (Netherlands) Divided into Nucl. Phys. A and Nucl. Phys. B Vol. Vol: 48; ISSN NUPHA
Country of Publication:
Country unknown/Code not available
Language:
English