A. Airapetian, et al. (HERMES Collaboration)
JHEP 1401 (2014) 077
Publication year: 2014

The beam-helicity asymmetry in associated electroproduction of real photons, epeγπN, in the Δ(1232)-resonance region is measured using the longitudinally polarized HERA positron beam and an unpolarized hydrogen target. Azimuthal Fourier amplitudes of this asymmetry are extracted separately for two channels, epeγπ0p and epeγπ+n, from a data set collected with a recoil detector. All asymmetry amplitudes are found to be consistent with zero.