Strangeness Photoproduction at the BGO-OD experiment

Abstract

The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremsstrahlung photon beam to investigate the excitation structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. In particular, this enables the investigation of strangeness photoproduction where t-channel exchange mechanisms play an important role. This also allows access to low momentum exchange kinematics where extended, molecular structure may manifest in reaction mechanisms. First key results at low t indicate a cusp-like structure in K+Σ0 photoproduction at W = 1900 MeV, line shapes and differential cross sections for K+Λ(1405)→ K+Σ0π0, and a peak structure in K0SΣ0 photoproduction. The peak in the K0SΣ0 channel appears consistent with meson-baryon generated states, where equivalent models have been used to describe the PC pentaquark candidates in the heavy charmed quark sector.