Searches for Exotic Hadrons at GlueX

Abstract

The search for hybrid mesons and the detailed study of their spectrum is the primary goal of the GlueX Experiment in Hall D at Jefferson Lab. The identification and study of hybrid mesons promises to provide unique insight into gluonic degrees of freedom in QCD and the nature of confinement. The experiment combines an intense photon beam with linear polarization peaking around 9 GeV incident on a liquid hydrogen target with a nearly hermetic spectrometer, allowing for the comprehensive study of charged and neutral particle final states. The first phase of the experiment has recently concluded, yielding a photoproduction data set of unprecedented size and quality. We report on the status of the analysis of this data, including measurements of polarization observables, progress in spectroscopic measurements of light mesons, and the measurement of the photoproduction of J/ψ near threshold, which is providing critical insight into the nature of the LHCb closed-charm pentaquark candidates.

Heavy Hybrid Decays in a Constituent Gluon Model

“…Longstanding interest in hybrid mesons continues because they offer a window into the unknown dynamics of nonperturbative gluonic degrees of freedom in Quantum Chromodynamics (QCD). In particular, robust experimental programs are underway by the GlueX collaboration at Jefferson Lab [1] and by the PANDA collaboration at FAIR [2]. The spectrum, radiative transitions, and strong decay widths are of interest to the experimental community as these are crucial to informing experimental design and the interpretation of experimental results.…”