GlueX

GlueX is a particle physics experiment located at the Thomas Jefferson National Accelerator Facility (JLab) accelerator. Its primary purpose is to better understand the nature of confinement in quantum chromodynamics (QCD) by identifying a spectrum of hybrid and exotic mesons generated by the excitation of the gluonic field binding the quarks. Such mesonic states are predicted to exist outside of the well-established quark model, but none have been definitively identified by previous experiments. A broad high-statistics survey of known light mesons up to and including the J / ψ {displaystyle J/psi } is also underway. GlueX is a particle physics experiment located at the Thomas Jefferson National Accelerator Facility (JLab) accelerator. Its primary purpose is to better understand the nature of confinement in quantum chromodynamics (QCD) by identifying a spectrum of hybrid and exotic mesons generated by the excitation of the gluonic field binding the quarks. Such mesonic states are predicted to exist outside of the well-established quark model, but none have been definitively identified by previous experiments. A broad high-statistics survey of known light mesons up to and including the J / ψ {displaystyle J/psi } is also underway. The experiment uses photoproduction (that is, the scattering of a real photon on a nucleon) to produce mesonic states. Unlike previous similar experiments, it uses linearly polarized photons, which allows the analysis of accumulated events for certain polarization observables that are thought to make identification of exotic states feasible. The GlueX detector was installed in the new Hall D (the fourth such hall at JLab) as part of the accelerator's upgrade to 12 GeV energy. GlueX began its first commissioning run in 2014, and first received 12 GeV electrons in 2015, the highest energy available at the CEBAF accelerator. Publication-quality physics data was accumulated during multi-weeks runs in the spring months of 2016, 2017, and 2018.