Progress on Neutron-Target Multipoles above 1 GeV

¹ The George Washington University, Washington, DC 20052, USA
² Duke University, Durham, NC 27708 USA
³ Mississippi State University, Mississippi State, MS 39762 USA
⁴ Institute of Theoretical and Experimental Physics, Moscow, 117259 Russia
⁵ INFN, Laboratory Nazionali di Frascati, 00044 Frascati, Italy
⁶ Theory Division, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
⁷ Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA

^a e-mail: igor@gwu.edu

Abstract

We report a new extraction of nucleon resonance couplings using π⁻ photo-production cross sections on the neutron. The world database for the process γn → π⁻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 diagrammatic technique taking into account the SAID phenomenological NN and πN 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.