Amplitude analysis ofγn→π−pdata above 1 GeV

Abstract

We report an extraction of nucleon resonance couplings using ${\ensuremath{\pi}}^{\ensuremath{-}}$ photoproduction cross sections on the neutron. The world database for the process $\ensuremath{\gamma}n\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}p$ above 1 GeV has quadrupled with the addition of differential cross sections from the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab in Hall B. Differential cross sections from CLAS have been improved with a final-state interaction determination using a diagrammatic technique taking into account the $NN$ and $\ensuremath{\pi}N$ final-state interaction amplitudes. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections significant changes are seen in the high-energy behavior of the Scattering Analysis Interactive Dial-in program cross sections and amplitudes.