Meson photoproduction at Jefferson Lab: from two-meson final states to meson-baryon spin-density matrices
Abstract
Recent progress in the understanding of meson photoproduction, obtained from the joint effort of the Joint Physics Analysis Center (JPAC) and the GlueX and CLAS experiments at Jefferson Lab, is reviewed. The photoproduction of the ηπ system is now well understood, from the a2(1320) resonance region to the high-mass region dominated by double Regge exchanges. Since the lightest hybrid meson, the π1(1600), is expected to decay predominantly into b1π, reactions with a recoiling Δ++ are promising channels for exotic searches. As a first step towards γp → b1 πΔ++, the complete angular distribution of γp → ρ-Δ++ with a linearly polarized photon beam is derived. It involves 56 double-index spin-density matrix elements, which describe the correlations between the ρ and the Δ decays. When the production amplitudes factorize, as is the case for the exchange of a single Regge pole, the intensity reduces to the product of the standard ρ and Δ decay distributions and depends on only 14 parameters.
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
- QCD phase structure at high baryon density
- Joint Constraints on the Hubble Constant and Cosmic Baryon Density from Localized Fast Radio Bursts and DESI DR2 Baryon Acoustic Oscillations
- A phenomenological approach to direct K* production and hadronic medium effects in nucleus-nucleus collisions at high baryon density
- An Algorithm for computing Three- and Four-Body Density Matrices from CASCI Wavefunction and AI-Assisted Code Optimization
BibTeX
@misc{mathieu2026meson,
title = {{Meson photoproduction at Jefferson Lab: from two-meson final states to meson-baryon spin-density matrices}},
author = {Vincent Mathieu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.35045},
eprint = {2609.35045},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.35045},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Meson photoproduction at Jefferson Lab: from two-meson final states to meson-baryon spin-density matrices
AU - Vincent Mathieu
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.35045
UR - https://arxiv.org/abs/2609.35045
AB - Recent progress in the understanding of meson photoproduction, obtained from the joint effort of the Joint Physics Analysis Center (JPAC) and the GlueX and CLAS experiments at Jefferson Lab, is reviewed. The photoproduction of the ηπ system is now well understood, from the a_2(1320) resonance region to the high-mass region dominated by double Regge exchanges. Since the lightest hybrid meson, the π_1(1600), is expected to decay predominantly into b_1π, reactions with a recoiling Δ^++ are promising channels for exotic searches. As a first step towards γp → b_1 πΔ^++, the complete angular distribution of γp → ρ^-Δ^++ with a linearly polarized photon beam is derived. It involves 56 double-index spin-density matrix elements, which describe the correlations between the ρ and the Δ decays. When the production amplitudes factorize, as is the case for the exchange of a single Regge pole, the intensity reduces to the product of the standard ρ and Δ decay distributions and depends on only 14 parameters.
ER -