Studying the meson photoproduction mechanism through spin-density matrix elements at GlueX

by Niklas Herrmann (Ruhr-Universitaet Bochum (DE))

Friday 16 Jan 2026, 14:30 → 15:15 Europe/Zurich

NB2/158 (RUB)

Abstract:

The primary goal of the GlueX experiment is the search for exotic mesons, states that are forbidden within the quark model but permitted by quantum chromodynamics. GlueX located at Jefferson Lab employs a linearly polarized photon beam in the energy range from 8.2 to 8.8 GeV on a liquid hydrogen target. Current searches for exotic hybrid mesons within the meson spectrum require an understanding of the production mechanism. An important experimental tool to study the production mechanism is the measurement of polarization observables as the Spin-Density Matrix Elements (SDMEs) with a linearly polarized photon beam. 
In this talk, I present the measurement of the polarized SDMEs in the photoproduction of $\rho^- \Delta^{++}$, using GlueX data from 2017 - 2018. 
The new GlueX data has significantly better statistical precision compared to the existing SLAC data and provides a precise measurement of the t-dependence of the SDMEs for the range $0.025$ to $1.4~\mathrm{GeV}^2$.