2002/11/18 by B. Borasoy, Eugenio Marco, E. Marco +1 · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevc.66.055208
published as Phys.Rev. C66 (2002) 055208 · 26 pages
openalex publication_date 2002/11/18 · arxiv created 2002/12/17 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The photoproduction and electroproduction of the \ensuremathη,\ensuremathη^\ensuremath' mesons on nucleons are investigated within a relativistic chiral unitary approach based on coupled channels. The s-wave potentials for electroproduction and meson-baryon scattering are derived from a chiral effective Lagrangian, which includes \ensuremathη^\ensuremath' as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangian such as the axial U(1) anomaly. The effective potentials are iterated in a Bethe-Salpeter equation and the cross sections for \ensuremathη,\ensuremathη^\ensuremath' photoproduction and electroproduction from nucleons are obtained. The results for the \ensuremathη^\ensuremath' photoproduction cross section on protons reproduce the appearance of an S11 resonance around 1.9 GeV observed at ELSA. The inclusion of electromagnetic form factors increases the predicted \ensuremathη electroproduction cross sections on the proton, providing a qualitative explanation for the hard form factor of the photocoupling amplitude observed at CLAS.