Ratios of Helicity Amplitudes for Exclusive rho-0 Electroproduction

Abstract

Exclusive rho^0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV^2 < Q^2 < 7.0 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t' < 0.4 GeV^2. Real and imaginary parts of the ratios of the natural-parity-exchange helicity amplitudes T_{11} (γ^*_T --> ρ_T), T_{01} (γ^*_T --> ρ_L), T_{10} (γ^*_L --> ρ_T), and T_{1-1} (γ^*_{-T} -->ρ_T) to T_{00} (γ^*_L --> ρ_L) are extracted from the data. For the unnatural-parity-exchange amplitude U_{11}, the ratio |U_{11}/T_{00}| is obtained. The Q^2 and t' dependences of these ratios are presented and compared with perturbative QCD predictions.

arXiv comment27 pages, 8 tables, 13 figures; minor textual changes on pages 2, 3,9, 10, 11, and some changes to the list of references

References in corpus (35)

• Gauge-Invariant Decomposition of Nucleon Spin and Its Spin-Off
• Wave Functions, Evolution Equations and Evolution Kernels from Light-Ray Operators of QCD
• Generalized Parton Distributions
• Deeply Virtual Compton Scattering
• Nonforward Parton Distributions
• Unraveling hadron structure with generalized parton distributions
• Hard Exclusive Reactions and the Structure of Hadrons
• Factorization for hard exclusive electroproduction of mesons in QCD
• The HERMES Spectrometer
• Nucleon Form Factors from Generalized Parton Distributions
• The role of the quark and gluon GPDs in hard vector-meson electroproduction
• Vector meson electroproduction at small Bjorken-x and generalized parton distributions
• Structure Functions are not Parton Probabilities
• Elastic Electroproduction of rho Mesons at HERA
• Diffractive Electroproduction of rho and phi Mesons at HERA
• The longitudinal cross section of vector meson electroproduction
• Diffractive Vector Meson Production at HERA: from Soft to Hard QCD
• Exclusive Electroproduction of ${\rho }^0$ and $J/\psi$ Mesons at HERA
• Exclusive rho^0 production in deep inelastic scattering at HERA
• The HERMES Dual-Radiator Ring Imaging Cerenkov Detector
• The target asymmetry in hard vector-meson electroproduction and parton angular momenta
• The Longitudinal Polarimeter at HERA
• Elastic Electroproduction of $\rh0$ and $J/\Psi$ Mesons at large $Q^2$ at HERA
• Exclusive Leptoproduction of rho^0 Mesons from Hydrogen at Intermediate Virtual Photon Energies
• Measurement of elastic electroproduction of phi mesons at HERA
• Measurement of the Spin-Density Matrix Elements in Exclusive Electroproduction of rho^0 Mesons at HERA
• Exclusive ${\rho }^0$ electroproduction on the proton at CLAS
• Polarization in diffractive electroproduction of light vector mesons
• Spin Density Matrix Elements in Exclusive rho^0 Electroproduction on 1H and 2H Targets at 27.5 GeV Beam Energy
• Exclusive ${\rho }^0$ meson electroproduction from hydrogen at CLAS
• Measurement of the Reaction ${\gamma }^{\ast }p\to \varphi p$ in Deep Inelastic $e^{+}p$ Scattering at HERA
• Vector meson production from a polarized nucleon
• Measurement of Angular Distributions and R= sigma_L/sigma_T in Diffractive Electroproduction of rho^0 Mesons
• On hard electroproduction of mesons: helicity flip amplitudes with tensor gluon contributions
• Production of Polarized Vector Mesons off Nuclei

Cited by in corpus (9)

• Insights into the Emergence of Mass from Studies of Pion and Kaon Structure
• A phenomenological study of helicity amplitudes of high energy exclusive leptoproduction of the rho meson
• Saturation effects in exclusive rhoT, rhoL meson electroproduction
• Deeply Virtual Compton Scattering at a Proposed High-Luminosity Electron-Ion Collider
• Prospects for quarkonium studies at the high-luminosity LHC
• Ratios of helicity amplitudes for exclusive ${\rho }^0$ electroproduction on transversely polarized protons
• Investigation of electroproduction of $\varphi$ mesons off protons
• Amplitudes ratios in ${\rho }^0$ leptoproductions and GPDs
• DVCS at HERMES