Title: Towards the hybrid meson photoproduction at JLab: unraveling pion exchange from a Regge theory perspective
Abstract: The GlueX experiment at Jefferson Lab is dedicated to charting the spectrum of light mesons through photoproduction, with a keen focus on the search for light hybrid mesons. Achieving this goal requires a precise theoretical comprehension of the underlying production mechanisms. In the GlueX energy regime, single meson photoproduction is primarily governed by the exchange of Regge trajectories, with unnatural parity exchanges, such as pion exchange, dominating in charge-exchange reactions at small momentum transfer. In this talk, I will concentrate on the pion photoproduction reaction, which offers a clean probe of the pion exchange mechanism. I will discuss the role of gauge invariance in pion exchange, relevant to approach its reggeization rigorously. Furthermore, I will review the ongoing and prospective efforts of the Joint Physics Analysis Center (JPAC) Collaboration in identifying and understanding the production mechanisms in more challenging reactions, essential for the eventual identification of exotic hybrid mesons.