Measuring Beam Spin Asymmetry of π- photoproduction off deuterium in the 8-10 GeV Range

Studying meson-photoproduction amplitudes is one of the powerful ways of learning about excited nucleon resonances. However, measurements on neutron targets, as well as on proton targets, are needed to fully disentangle isoscalar and isovector couplings, and no feasible neutron target has ever been built. One common technique is to study photoproduction from neutrons in deuterium in quasi-free kinematics. Such measurements have previously been performed with beam energies reaching up to a few GeV. Data from the Hall D Short-Range Correlations / Color-Transparency Experiment, conducted at Jefferson Lab in the fall of 2021, may extend our knowledge out to the 8-10 GeV range. Using the higher beam energy available at Hall D, combined with the capabilities of the GlueX spectrometer, the fully exclusive γ d -> π- p p reaction can be reconstructed. The experiment scattered a linearly polarized photon beam from deuterium, helium, and carbon targets, with a minimally selective trigger, using GlueX to reconstruct the produced charged particles. I have worked to identify events with a deuteron target which produced a single ??- meson. By comparing the azimuth of the meson and the polarization of the photon beam, a measurement of the ?? beam spin asymmetry of the photoproduction of ??- mesons from neutrons in deuterium can be made in the 8-10 GeV range. I will present the status of the analysis and projected uncertainties.