Nucleon Resonance Excitation with Photons

por Cornelius Bennhold (George Washington University)

martes 12 dic. 2000 12:30 → 13:30 Europe/Madrid

Sala Seminarios IFIC (Edf. Institutos de Investigación)

Just like atomic and nuclear systems, the nucleon has an excitation spectrum which is a consequence of its nature as a composite system. This resonance spectrum is a reflection of the underlying strong interaction, namely QCD. In contrast to nuclear and atomic systems these nucleon resonances have large widths and can be difficult to separate experimentally. On the other hand, QCD is nonperturbative in this energy region making a prediction of the spectrum directly from QCD very difficult. Since nucleon resonances can be excited with photons and mesons, methods are presented to investigate such excited states through the photoproduction of pions, etas and kaons in a coupled-channels framework. The role of polarization observables is pointed out in the search for the so-called "missing resonances".Just like atomic and nuclear systems, the nucleon has an excitation spectrum which is a consequence of its nature as a composite system. This resonance spectrum is a reflection of the underlying strong interaction, namely QCD. In contrast to nuclear and atomic systems these nucleon resonances have large widths and can be difficult to separate experimentally. On the other hand, QCD is nonperturbative in this energy region making a prediction of the spectrum directly from QCD very difficult. Since nucleon resonances can be excited with photons and mesons, methods are presented to investigate such excited states through the photoproduction of pions, etas and kaons in a coupled-channels framework. The role of polarization observables is pointed out in the search for the so-called "missing resonances".