Near threshold angular distributions for the 2H(γ, Λ)X reaction. (30th June 2016) - Beckford, B.
Abstract: A study of the $^2$ H$({\gamma}, {\Lambda})$ X reaction was performed using a tagged photon beam at the Research Center for Electron Photon Science (ELPH), Tohoku University. The photoproduced $\Lambda$ was measured in the $p{\pi^{-}}$ decay channel by the upgraded Neutral Kaon Spectrometer (NKS2+). The momentum integrated differential cross section was determined as a function of the scattering angle of ${\Lambda}$ in the laboratory frame for five energy bins. Our results indicated a peak in the cross section at angles smaller than $\cos\theta^{\mathrm{LAB}}_{\Lambda}$ = $0.96$ . The experimentally obtained angular distributions were compared to isobar models, Kaon-Maid (KM) and Saclay-Lyon A (SLA), in addition to the composite Regge-plus-resonance (RPR) model. Both SLA(r$K_{1}K_{\gamma}$ = $-1.4$ ) and RPR describe the data quite well in contrast to the KM model, which substantially under-predicted the cross section at the most forward angles. With the anticipated finalized data on ${\Lambda}$ integrated and momentum dependent differential cross sections of $^2$ H$({\gamma}, {\Lambda})$ X [M. Kaneta et al., Nucl. Phys. A 914, 69 (2013)], we present our findings on the angular distributions.