Beam-helicity asymmetry arising from deeply virtual Compton scattering measured with kinematically complete event reconstruction

Abstract

The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized HERA positron beam scattering off an unpolarized hydrogen target is measured at HERMES. The asymmetry arises from deeply virtual Compton scattering and its interference with the Bethe--Heitler process. Azimuthal amplitudes of the beam-helicity asymmetry are extracted from a data sample consisting of $ep\to ep\gamma$ events with detection of all particles in the final state including the recoiling proton. The installation of a recoil detector, while reducing the acceptance of the experiment, allows the elimination of background from $ep\to eN\pi \gamma$ events, which was estimated to contribute an average of about 12% to the signal in previous HERMES publications. The removal of this background from the present data sample is shown to increase the magnitude of the leading asymmetry amplitude by 0.054 +/- 0.016 to -0.328 +/- 0.027 (stat.) +/- 0.045 (syst.).

References in corpus (33)

• Gauge-Invariant Decomposition of Nucleon Spin and Its Spin-Off
• Wave Functions, Evolution Equations and Evolution Kernels from Light-Ray Operators of QCD
• Deeply Virtual Compton Scattering
• Impact Parameter Dependent Parton Distributions and Off-Forward Parton Distributions for $\zeta \to 0$
• Scaling Limit of Deeply Virtual Compton Scattering
• Theory of deeply virtual Compton scattering on the nucleon
• Single-spin asymmetries: the Trento conventions
• LEPTO 6.5 - A Monte Carlo Generator for Deep Inelastic Lepton-Nucleon Scattering
• Deeply virtual electroproduction of photons and mesons on the nucleon : leading order amplitudes and power corrections
• Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering
• The HERMES Spectrometer
• Observation of exclusive DVCS in polarized electron beam asymmetry measurements
• Measurement of deeply virtual Compton scattering at HERA
• Deeply virtual Compton scattering at small x_B and the access to the GPD H
• Deeply Virtual Compton Scattering Beam-Spin Asymmetries
• Measurement of Deeply Virtual Compton Scattering at HERA
• Scaling Tests of the Cross Section for Deeply Virtual Compton Scattering
• A measurement of the Q^2, W and t dependences of deeply virtual Compton scattering at HERA
• Measurement of Deeply Virtual Compton Scattering and its t-dependence at HERA
• Deeply Virtual Compton Scattering and its Beam Charge Asymmetry in e^\pm p Collisions at HERA
• The Beam--Charge Azimuthal Asymmetry and Deeply Virtual Compton Scattering
• Beam-helicity and beam-charge asymmetries associated with deeply virtual Compton scattering on the unpolarised proton
• The Longitudinal Polarimeter at HERA
• Measurement of Deeply Virtual Compton Scattering at HERA
• Measurement of Azimuthal Asymmetries With Respect To Both Beam Charge and Transverse Target Polarization in Exclusive Electroproduction of Real Photons
• Cross sections for hard exclusive electroproduction of pi+ mesons on a hydrogen target
• Separation of contributions from deeply virtual Compton scattering and its interference with the Bethe--Heitler process in measurements on a hydrogen target
• Future Measurements of Deeply Virtual Compton Scattering at HERMES
• Pion production in deeply virtual Compton scattering
• RADGEN 1.0. Monte Carlo Generator for Radiative Events in DIS on Polarized and Unpolarized Targets
• The HERMES Recoil Detector
• Transverse target-spin asymmetry associated with DVCS on the proton and a resulting model-dependent constraint on the total angular momentum of quarks in the nucleon
• Polarisation at HERA - Reanalysis of the HERA II Polarimeter Data -

Cited by in corpus (35)

• The Spin Structure of the Nucleon
• Forces inside hadrons: pressure, surface tension, mechanical radius, and all that
• Generalized Parton Distributions in the valence region from Deeply Virtual Compton Scattering
• Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions
• The E00-110 experiment in Jefferson Lab's Hall A: Deeply Virtual Compton Scattering off the Proton at 6 GeV
• The Hadronic Final State at HERA
• On timelike and spacelike deeply virtual Compton scattering at next to leading order
• Deeply Virtual Compton Scattering to the twist-four accuracy: Impact of finite-$t$ and target mass corrections
• Description and interpretation of DVCS measurements
• Longitudinal target-spin asymmetries for deeply virtual Compton scattering
• Nucleon generalized form factors from two-flavor lattice QCD
• Deeply Virtual Compton Scattering at a Proposed High-Luminosity Electron-Ion Collider
• HERMES impact for the access of Compton form factors
• First Exclusive Measurement of Deeply Virtual Compton Scattering off ${}^4$He: Toward the 3D Tomography of Nuclei
• Deeply virtual Compton scattering cross section at high Bjorken $x_B$
• A new mechanism to enhance primordial tensor fluctuations in single field inflation
• Twist-3 GPDs in Deeply-Virtual Compton Scattering
• 2D energy-momentum tensor distributions of nucleon in a large-$N_c$ quark model from ultra-relativistic to non-relativistic limit
• Higher-Order Kinematical Effects in Deeply Virtual Compton Scattering
• Twist-three cross-sections in deeply virtual Compton scattering
• The phenomenology of trapped inflation
• Prospects for quarkonium studies at the high-luminosity LHC
• Twist-3 Generalized Parton Distribution for the Proton from Basis Light-Front Quantization
• Status of DVMP, DVCS and GPDs
• Generalized Parton Distributions and Deeply Virtual Compton Scattering
• The HERMES Recoil Detector
• Single Field Inflation in Supergravity with a $U(1)$ Gauge Symmetry
• Beam-helicity asymmetry in associated electroproduction of real photons $ep\to e\gamma \pi N$ in the $\Delta$-resonance region
• Deeply virtual Compton scattering in the tensor-pomeron approach
• Phase transitions in heavy-quark QCD from an effective theory
• Probing nucleon spin structure in deep-inelastic scattering, proton-proton collisions and Drell-Yan processes
• Lepton mass effects in the Bethe-Heitler process
• DVCS at HERMES
• Deeply virtual Compton scattering off the neutron
• Assessing the impact of the electron ion collider in China on Deeply Virtual Compton Scattering