On pion nucleon resonances

helicity amplitudes, isospin, partial wave expansions, particle physics, Regge poles, pion nucleon resonances

Marx-Oberländer, Egon ; Gell-Mann, Murray (advisor)

University:California Institute of Technology

Department:Physics, Mathematics and Astronomy

关键词: helicity amplitudes, isospin, partial wave expansions, particle physics, Regge poles, pion nucleon resonances;   

Others  :  https://thesis.library.caltech.edu/6960/1/Marx-Oberlander_e_1963.pdf

美国|英语

来源: Caltech THESIS

【 摘 要 】

This thesis shows a method for setting up a numerical computation to find resonances in the pion-nucleon system. It takes into account inelastic reactions through a generalized N/D method, and problems introduced by unstable particles are analyzed. General formulae are calculated for the kinematics of reactions involving the πN, ρN, ωN and πN* channels, relating sets of Lorents invariant amplitudes (free of kinematical singularities) to helicity amplitudes in a form that exhibits the reflection symmetry when the total energy W is replaced by - W, and a simple form is found for the partial wave expansions. A detailed discussion of the isospin part of the equations is included.