Hadron Spectroscopy in Photoproduction

TL;DR

Recent advances in photoproduction experiments and facilities have revitalized hadron spectroscopy, enabling the study of new and exotic hadrons and expanding understanding of quark and gluonic contributions beyond the traditional quark model.

Contribution

This paper reviews the potential of photoproduction in hadron spectroscopy across existing and upcoming experimental facilities, highlighting new opportunities and theoretical developments.

Findings

Photoproduction offers access to a wide range of hadronic states.

New facilities like GlueX and EIC enhance spectroscopy capabilities.

Recent experiments have identified many new and unexpected hadrons.

Abstract

Recent decades have seen a resurge of interest in hadron spectroscopy, driven by new, high-luminosity experiments which have identified many new hadrons, both expected and unexpected. The large number of unexpected hadrons suggest contributions from additional quark and gluonic degrees of freedom to the hadronic spectrum beyond the basic quark model. Photoproduction has emerged as an attractive process to study hadron spectroscopy, due to the range of states accessible in new and planned experimental facilities, complimentary kinematics to other experiments where rescattering effects near thresholds are reduced, and advances in our theoretical understanding of these reactions. This white paper reviews the prospects for hadron spectroscopy from three major existing and proposed facilities: the current GlueX experiment, the planned Electron-Ion Collider, and a proposed JLab 24 GeV upgrade.