Spin-Density Matrix Elements in the Reaction γp → ρ-Δ++ at GlueX
Abstract
The GlueX experiment, located in Hall D at Jefferson Lab, aims to map the full spectrum of light-quark mesons with an emphasis on hybrid mesons, states in which the gluonic field is excited and contributes to the quantum numbers of the meson. The search for exotic hybrid mesons requires a detailed understanding of the underlying production mechanisms. Polarization observables, such as the spin-density matrix elements (SDMEs), are an important experimental tool to investigate these mechanisms. The measurement of the unpolarized and polarized SDMEs in the photoproduction of ρ-Δ++ using GlueX data is reported. In this analysis, for the first time, the correct full formalism is applied in which the upper mesonic and lower baryonic systems are described by a joint spin-density matrix. A factorized model yields results consistent with those of the full model, suggesting that this simplified description may also be suitable for other reactions involving meson-baryon final states.
Related
- First measurement of polarized spin-density matrix elements and differential cross sections dσ/dt in ω photoproduction off the proton for 2.7 < Eγ < 5.2 GeV using CLAS at Jefferson Lab
- Breaking the Spin Degeneracy for Distributions of Off-Diagonal Scattering Matrix Elements in the Case of Symplectic Symmetry
- Spin density matrix for high-spin particles
- MadSpin2: automated spin-entangled decays of heavy resonances via the spin-density matrix formalism
- Density-matrix quantum kinetics of spin-mode crossover and ac Edelstein response in spin--orbit-coupled chiral metals
BibTeX
@misc{herrmann2026spindensity,
title = {{Spin-Density Matrix Elements in the Reaction $γp \to ρ^-Δ^++$ at GlueX}},
author = {Niklas Herrmann and Farah Afzal for the GlueX Collaboration},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.03072},
eprint = {2610.03072},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.03072},
}
RIS
TY - UNPB
TI - Spin-Density Matrix Elements in the Reaction γp → ρ^-Δ^++ at GlueX
AU - Niklas Herrmann
AU - Farah Afzal for the GlueX Collaboration
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.03072
UR - https://arxiv.org/abs/2610.03072
AB - The GlueX experiment, located in Hall D at Jefferson Lab, aims to map the full spectrum of light-quark mesons with an emphasis on hybrid mesons, states in which the gluonic field is excited and contributes to the quantum numbers of the meson. The search for exotic hybrid mesons requires a detailed understanding of the underlying production mechanisms. Polarization observables, such as the spin-density matrix elements (SDMEs), are an important experimental tool to investigate these mechanisms. The measurement of the unpolarized and polarized SDMEs in the photoproduction of ρ^-Δ^++ using GlueX data is reported. In this analysis, for the first time, the correct full formalism is applied in which the upper mesonic and lower baryonic systems are described by a joint spin-density matrix. A factorized model yields results consistent with those of the full model, suggesting that this simplified description may also be suitable for other reactions involving meson-baryon final states.
ER -