We report a new extraction of nucleon resonance couplings using pi- photoproduction cross sections on the neutron. The world database for the process gamma n --> pi- p above 1 GeV has quadrupled with the addition of new 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 new final-state interaction determination using a diagramatic technique taking into account the NN and piN final-state interaction amplitudes. Resonance couplings have been extracted and compared to previous determinations. With the addition of these new cross sections, significant changes are seen in the high-energy behavior of the SAID cross sections and amplitudes.
@article{arxiv.1203.4412,
title = {Amplitude analysis of gamma n --> pi- p data above 1 GeV},
author = {W. Chen and H. Gao and W. J. Briscoe and D. Dutta and A. E. Kudryavtsev and M. Mirazita and M. Paris and P. Rossi and S. Stepanyan and I. I. Strakovsky and V. E. Tarasov and R. L. Workman},
journal= {arXiv preprint arXiv:1203.4412},
year = {2013}
}