Determining pseudoscalar meson photo-production amplitudes from complete experiments

Understand

We review the development of the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single, double and triple-polarization terms involving 16 spin-dependent observables.

• We examine the different conventions that have been used by different authors, and we present expressions that allow the direct numerical calculation of any pseudoscalar meson photo-production observables with arbitrary spin projections from the Chew-Goldberger-Low-Nambu amplitudes.
• We use this numerical tool to clarify apparent sign differences that exist in the literature.
• We also present analytic expressions that determine the recoil baryon polarization, together with examples of their potential use with quasi-4pi detectors to deduce observables.