Baryon Spectroscopy at GlueX

High-energy electrons and photons are remarkably clean probes of hadronic matter, providing a microscope for examining atomic nuclei and the strong nuclear force. The GlueX experiment in Hall D at Jefferson Laboratory has accumulated high-statistics samples of photoproduction data in recent years. Complementary to nucleon structure studies in deep inelastic scattering experiments, nucleon excitations provide the unique opportunity to explore the many aspects of non-perturbative QCD. While the last few years have seen significant progress toward the mapping of the nucleon and Δ spectrum, experimental information on the spectrum, structure, and decays of strangeness -2 Ξ baryons remains sparse compared to non-strange and strangeness -1 baryons. Moreover, the photo-induced production mechanism for these so-called Cascade resonances is not well understood and expected to proceed via highly excited intermediate singly strange hyperons in reactions such as γ p→ K Y^* (e.g. Λ ^*, Σ ^*)→ KK Ξ ^(*) . Copious data for excited strangeness -1 baryons have also been collected with GlueX, e.g. for the Λ (1405) and Λ (1520) , along with the data for Cascade baryons in this experimental hyperon program.