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 $K^{+}\hat{I}{\pounds }^0$ photoproduction at $W=1900$\,MeV, line shapes and differential cross sections for $K^{+}\hat{I}›$(1405)$\to K^{+}\hat{I}{\pounds }^0\ddot{I}{€}^0$, and a peak structure in $K_S^0\hat{I}{\pounds }^0$ photoproduction. The peak in the $K_S^0\hat{I}{\pounds }^0$ channel appears consistent with meson-baryon generated states, where equivalent models have been used to describe the $P_C$ pentaquark candidates in the heavy charmed quark sector.

Proceedings of The 12th International Workshop on the Physics of Excited Nucleons (NSTAR 2019)