Resonances in Complex Diagrams of the $pi$N-Forward Scattering Amplitude; RESONANZEN IM KOMPLEXEN DIAGRAMM DER $pi$N-VORWARTSSTREUAMPLITUDE

Technical Report · Mon Jan 01 04:00:00 EST 1962

OSTI ID:4784432

Hoehler, G; Ebel, G

The pi N-forwaid scattering amplitudes were calculated from the total cross sections, using the dispersion relations and the optical theorem. In order to facilitate the discussion of the nucleon resonances, the results are given as diagrams, showing the energy dependence of the complex vectors q F/sub b/ for total isospin I = 1/2, 3/2, and charge exchange scattering (q = pion momentum, F/ sub b/ = D/sub b/ + i A/sub b/ forward scattering amplitude, both in the c.m. system). ln this repiesentation the contribution of an elastic resonant partial wave is a circle of radius (2J + 1)/4 which is described in a counter-clockwise direction as the energy increases. In the inelastic case the radius is smaller by an amount which depends on the absorption. Several arguments are given in favor of the opinion that a zero order description of photoproduction of pions is probably as complicated as the description of pion-nucleon scattering. In particular it is not justified to neglect the Born term for the pi /sup 0/ production and the M 1 P 1/2 amplitude of the Born term for the pi /sup +/ production. (auth)

• Research Organization: Karlsruhe, Germany. Technische Hochschule. Institut fur Theoretische Kernphysik
• NSA Number: NSA-16-032274
• OSTI ID: 4784432
• Report Number(s): NP-12032
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BORN APPROXIMATION
DISPERSION RELATIONS
ELEMENTARY PARTICLES
FIELD THEORY
OPTICAL THEOREM
PERTURBATION THEORY
PHYSICS
QUANTUM MECHANICS
SCATTERING
SCATTERING AMPLITUDE