Measurement of Spin-Density Matrix Elements in $\rho (770)$ Production with a Linearly Polarized Photon Beam at $E_{\gamma }=8.2-8.8\text{GeV}$

Abstract

The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized $8.5\text{GeV}$ photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson $\rho$(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of $s$-channel helicity conservation at small squared four-momentum transfer $t$ and are able to extract the $t$-dependence of natural and unnatural-parity exchange contributions to the production process in detail. We confirm the dominance of natural-parity exchange over the full $t$ range. We also find that helicity amplitudes in which the helicity of the incident photon and the photoproduced $\rho (770)$ differ by two units are negligible for $-t<0.5{\text{GeV}}^2/c^2$.

arXiv comment15 pages, 11 figures

References in corpus (16)

• The GlueX Beamline and Detector
• Measurement of the beam asymmetry $\Sigma$ for ${\pi }^0$ and $\eta$ photoproduction on the proton at $E_{\gamma }=9$ GeV
• Polarization observables in vector meson photoproduction
• Construction and Performance of the Barrel Electromagnetic Calorimeter for the GlueX Experiment
• Moments of angular distribution and beam asymmetries in $\eta {\pi }^0$ photoproduction at GlueX
• The GlueX Start Counter Detector
• Vector Meson Photoproduction with a Linearly Polarized Beam
• Beam Asymmetry $\mathbf{\Sigma }$ for the Photoproduction of $\eta$ and ${\eta }^{\prime }$ Mesons at ${\mathbf{E}}_{\gamma }=8.8$GeV
• Design and construction of a high-energy photon polarimeter
• The Central Drift Chamber for GlueX
• Spin Information from Vector-Meson Decay in Photoproduction
• Constraints on vector meson photoproduction spin observables
• Measurement of beam asymmetry for ${\pi }^{-}{\Delta }^{++}$ photoproduction on the proton at $E_{\gamma }$=8.5 GeV
• Measurement of Spin Density Matrix Elements in $\Lambda (1520)$ Photoproduction at 8.2-8.8 GeV
• Measurement of the Photon Beam Asymmetry in $\vec{\gamma }p\to K^{+}{\Sigma }^0$ at $E_{\gamma }=8.5$ GeV
• Spin-Density Matrix Elements for Vector Meson Photoproduction at GlueX

Cited by in corpus (4)

• Ambiguities in the Partial-Wave Analysis of the Photoproduction of Pairs of Pseudoscalar Mesons
• Measurement of Spin-Density Matrix Elements in $\varphi (1020)\to K_S^0{K}_L^0$ Photoproduction with a Linearly Polarized Photon Beam at $E_{\gamma }=8.2-8.8$ GeV
• Combined analysis of the data on cross sections and spin density matrix elements for $K^{\ast }\Sigma$ photoproduction reactions
• Elliptical Polarization in Partial Wave Analysis of Two Spinless Meson Photoproduction