Yield extraction for γd → ΛX reaction

Experimental cross sections of hyperon-deuteron elastic scattering are needed for the understanding of the baryon-baryon interaction and the composition of neutron stars. Data taken with the CEBAF Large Acceptance Spectrometer (CLAS) on a liquid deuterium target in the high luminosity E06-103 (g13) photoproduction experiment, have provided statistically significant Λ-deuteron elastic-scattering event sample. In g13, the Λ beam is first photoproduced on a deuteron and then scattered on another deuteron in the same target. To obtain cross-section estimates, the number of the beam Λs must be determined. In this work, we present the extraction of the yield of the γd→ΛX reaction from g13 data. Λ hyperons are reconstructed using their decay into a proton and π⁻ pair (pπ⁻). Kinematic cuts are applied to reduce the background from pion photoproduction. Background subtraction performed on event distributions over the pπ⁻ invariant mass yields the number of ΛX events for hyperon momenta from 500 MeV/c to 1500 MeV/c. A parallel analysis of the exclusive γd→ΛK⁺n reaction has allowed to quantify the systematic error due to our assumption for the shape of the signal in the background subtraction to be of the order of 10%. In this presentation, we will show details of the analysis, our preliminary results, and an outlook.