Differential Cross Section Measurements for γn→π-p Above the First Nucleon Resonance Region

Abstract

The quasifree γd→π-p(p) differential cross section has been measured with CLAS at photon beam energies Eγ from 0.445 to 2.510 GeV (corresponding to W from 1.311 to 2.366 GeV) for pion center-of-mass angles cosθπc.m. from -0.72 to 0.92. A correction for final state interactions has been applied to these data to extract the γn→π-p differential cross sections. These cross sections are quoted in 8428 (Eγ,cosθπc.m.) bins, a factor of nearly 3 increase in the world statistics for this channel in this kinematic range. These new data help to constrain coupled-channel analysis fits used to disentangle the spectrum of N∗ resonances and extract their properties. Selected photon decay amplitudes N∗→γn at the resonance poles are determined for the first time and are reported here. © 2017 American Physical Society