Speaker
Description
In experimental hadron spectroscopy, we are concerned with indirect measurements of short-lived bound states, known as resonances. While many of these resonances can be described within the quark model, some have quantum numbers that are forbidden by a two- or three-quark system, meaning that they must have some other internal structure. Resonances themselves are complex poles of the scattering matrix, while what we observe experimentally is constrained to the real axis of the complex plane. To extract physical values from the resonance peak, such as mass, decay width, and quantum numbers, we typically use a Breit-Wigner function to describe the pole, alongside a partial-wave analysis. However, for large decay width and/or multiple nearby resonances, this framework violates key concepts such as unitarity. One notable alternative that does not have these issues is the K-matrix formalism. The K-matrix formalism also allows for a coupled-channel analysis, where multiple different production mechanisms and decays are taken into account simultaneously. A coupled-channel analysis also has the benefit of using well-known channels to constrain less confident ones. Using data from GlueX, we plan to perform a coupled channel analysis focusing on potential exotic mesons, starting with a partial-wave analysis of $\gamma p \rightarrow pK^+K^-$. This channel has the potential for a scalar glueball, and will serve as a high confidence channel to help constrain others in the full analysis.