Measurement of the Beam-Normal Single-Spin Asymmetry for Elastic Electron Scattering from ${}^{12}$C and ${}^{27}$Al

Abstract

We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries $B_n$ on ${}^{12}$C and ${}^{27}$Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of $B_n$ on ${}^{12}$C and provide a first measurement on ${}^{27}$Al. The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average lab scattering angle for both targets was 7.7 degrees, and the average $Q^2$ for both targets was 0.02437 GeV${}^2$ (Q=0.1561 GeV). The asymmetries are $B_n$ = -10.68 $\pm$ 0.90 stat) $\pm$ 0.57 (syst) ppm for ${}^{12}$C and $B_n$ = -12.16 $\pm$ 0.58 (stat) $\pm$ 0.62 (syst) ppm for ${}^{27}$Al. The results are consistent with theoretical predictions, and are compared to existing data. When scaled by Z/A, the Q-dependence of all the far-forward angle (theta < 10 degrees) data from ${}^1$H to ${}^{27}$Al can be described by the same slope out to $Q\approx 0.35$ GeV. Larger-angle data from other experiments in the same Q range are consistent with a slope about twice as steep.

arXiv commentMinor changes after refereeing; version as accepted for Physical Review C. Cosmetic changes to several figures, one author added. 22 pages, 8 figures

References in corpus (46)

• Two-photon exchange and elastic electron-proton scattering
• How to reconcile the Rosenbluth and the polarization transfer method in the measurement of the proton form factors
• Reduced hadronic uncertainty in the determination of $V_{ud}$
• Partonic calculation of the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer
• Precision Measurement of the Weak Charge of the Proton
• Superscaling of Inclusive Electron Scattering from Nuclei
• First Determination of the Weak Charge of the Proton
• Measurement of the two-photon exchange contribution to the elastic $e^{\pm }p$ scattering cross sections at the VEPP-3 storage ring
• Two-photon exchange in elastic electron-proton scattering
• Measurement of the vector analyzing power in elastic electron-proton scattering as a probe of double photon exchange amplitudes
• Towards a resolution of the proton form factor problem: new electron and positron scattering data
• Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment
• Measurement of the Transverse Beam Spin Asymmetry in Elastic Electron Proton Scattering and the Inelastic Contribution to the Imaginary Part of the Two-Photon Exchange Amplitude
• A high-precision polarimeter
• Model-dependence of the $\gamma Z$ dispersion correction to the parity-violating asymmetry in elastic $ep$ scattering
• Dispersion $\gamma Z$-box correction to the weak charge of the proton
• Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering
• gamma-Z corrections to forward-angle parity-violating e-p scattering
• Parity-Violating Electron Scattering and the Electric and Magnetic Strange Form Factors of the Nucleon
• New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei
• Beam normal spin asymmetry in elastic lepton-nucleon scattering
• Collinear Photon Exchange in the Beam Normal Polarization Asymmetry of Elastic Electron-Proton Scattering
• New formulation of gamma-Z box corrections to the weak charge of the proton
• Gamma-Z box contributions to parity violating elastic e-p scattering
• The P2 Experiment - A future high-precision measurement of the electroweak mixing angle at low momentum transfer
• Constrained gamma-Z interference corrections to parity-violating electron scattering
• Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering
• Analyzing power in elastic scattering of the electrons off a spin-0 target
• Coulomb distortion of relativistic electrons in the nuclear electrostatic field
• Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasi-elastic Electron-Deuteron Scattering
• The Vector Analyzing Power in Elastic Electron-Nucleus Scattering
• Measurement of the Target-Normal Single-Spin Asymmetry in Quasi-Elastic Scattering from the Reaction ${}^3$He${}^{\uparrow }(e,e^{\prime })$
• Precision Electron-Beam Polarimetry using Compton Scattering at 1 GeV
• Two-photon exchange corrections to elastic $e^{-}$-proton scattering: Full dispersive treatment of $\pi N$ states at low momentum transfers
• The Vector Analyzing Power in Elastic Electron-Proton Scattering
• Beam normal spin asymmetry for the $ep\to e\Delta (1232)$ process
• Beam normal spin asymmetry in the quasi-RCS approximation
• Quark-hadron duality constraints on γZ box corrections to parity-violating elastic scattering
• Doubly virtual Compton scattering and the beam normal spin asymmetry
• Modification of electromagnetic structure functions for the $\gamma Z$-box diagram
• A novel comparison of Møller and Compton electron-beam polarimeters
• Beam-normal single-spin asymmetry in elastic scattering of electrons from a spin-0 nucleus
• Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering off ${}^{28}$Si and ${}^{90}$Zr
• Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering
• Study of Two-Photon Exchange via the Beam Transverse Single Spin Asymmetry in Electron-Proton Elastic Scattering at Forward Angles over a Wide Energy Range
• First Measurement of the Beam Normal Single Spin Asymmetry in $\Delta$ Resonance Production by $Q_{\mathrm{weak}}$

Cited by in corpus (3)

• The Present and Future of QCD
• New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering Over a Range of Spin-0 Nuclei
• First Determination of the 27Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement