Measurement of the Neutral Weak Form Factors of the Proton

Abstract

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G_E^s. The result, A=-14.5 +- 2.2 ppm, is consistent with the electroweak Standard Model and no additional contributions from strange quarks. In particular, the measurement implies G_E^s + 0.39G_M^s = 0.023 +- 0.034 (stat) +- 0.022 (syst) +- 0.026 (delta G_E^n), where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor.

10 pages, 4 figures, submitted to Phys. Rev. Lett

Cited by in corpus (64)

• Parity Violating Measurements of Neutron Densities
• Chiral Perturbation Theory and Baryon Properties
• A way forward in the study of the symmetry energy: experiment, theory, and observation
• Weak magnetism for antineutrinos in supernovae
• The Strange Quark Contribution to the Proton's Magnetic Moment
• Parity-violating electroweak asymmetry in $\vec{e}p$ scattering
• A Measurement of the Electric Form Factor of the Neutron through $\vec{d}(\vec{e},e^{\prime }n)p$ at $Q^2=0.5$ (GeV/c)${}^2$
• Pion-nucleon scattering inside the Mandelstam triangle
• The Transverse Asymmetry ${\mathbf{A}}_{{\mathbf{T}}^{\prime }}$ from Quasi-elastic ${}^3\overrightarrow{\mathrm{He}}(\vec{e},e^{\prime })$ Process and the Neutron Magnetic Form Factor
• Parity-Violating Electron Scattering from 4He and the Strange Electric Form Factor of the Nucleon
• First Determination of the Weak Charge of the Proton
• Flavor Asymmetry of Light Quarks in the Nucleon Sea
• The SAMPLE Experiment and Weak Nucleon Structure
• New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors
• $\varphi$ and $\omega$ Meson Production in pp Reactions at $p_{lab}$=3.67 GeV/c
• Measurement of the vector analyzing power in elastic electron-proton scattering as a probe of double photon exchange amplitudes
• Low lying $qqqq\bar{q}$ states in the baryon spectrum
• Parity-Violating Electron Scattering and Neucleon Structure
• Electroweak Measurements of Neutron Densities in CREX and PREX at JLab, USA
• PWIA Extraction of the Neutron Magnetic Form Factor from Quasi-Elastic 3He(e,e') at Q^2 = 0.3 to 0.6 (GeV/c)^2
• Strange nucleon form factors in the perturbative chiral quark model
• Nucleon Structure and Parity-Violating Electron Scattering
• Parity-Violating Electron Scattering and the Electric and Magnetic Strange Form Factors of the Nucleon
• Incorporating Chiral Symmetry and Heavy Quark Theory in Extrapolations of Octet Baryon Charge Radii
• Electromagnetic Form Factors of Nucleons in a Light-cone Diquark Model
• Strange chiral nucleon form factors
• The Proton Elastic Form Factor Ratio at Low Momentum Transfer
• The anapole form factor of the nucleon
• The P2 Experiment - A future high-precision measurement of the electroweak mixing angle at low momentum transfer
• Neutrino-nucleus quasi-elastic scattering and strange quark effects
• The Nucleon Anapole Form Factor in Chiral Perturbation Theory to Sub-leading Order
• Neutrino neutral-current elastic scattering on 12C
• Interpreting the Neutron's Electric Form Factor: Rest Frame Charge Distribution or Foldy Term?
• Spectral Content of Isoscalar Nucleon Form Factors
• Strangeness Form Factors of the Proton in the Chiral Quark Model
• Relativistic Green's function approach to parity-violating quasielastic electron scattering
• Strange-quark contribution to the ratio of neutral- to charged-current cross sections in neutrino-nucleus scattering
• The Chiral Extrapolation of Strange Matrix Elements in the Nucleon
• Mesonic Anapole Form Factors of the Nucleons
• Electroweak Radiative Corrections to Parity-Violating Electroexcitation of the $\Delta$
• A photon calorimeter using lead tungstate crystals for the CEBAF Hall A Compton polarimeter
• Flavor Structure of the Nucleon Sea
• Strangeness content of the nucleon in quasielastic neutrino-nucleus reactions
• Isospin violation and the proton's neutral weak magnetic form factor
• Strange Vector Form Factors from Parity-Violating Electron Scattering
• K* nucleon hyperon form factors and nucleon strangeness
• Strange form factors and Chiral Perturbation Theory
• Physics of the Nucleon Sea Quark Distributions
• Measuring the surface thickness of the weak charge density of nuclei
• The full weak charge density distribution of 48Ca from parity violating electron scattering
• Helicity asymmetries in neutrino-nucleus interactions
• Baryon form factors: Model-independent results
• Neutral weak currents in pion electroproduction on the nucleon
• Open Questions in High Energy Spin Physics
• Lepton mass effects for beam-normal single-spin asymmetry in elastic muon-proton scattering
• Study of stochastic estimates of quark loops with unbiased subtraction
• Recent Results from Jefferson Lab
• Flux-integrated semiexclusive cross sections for charged-current quasielastic and neutral-current elastic neutrino scattering off ${}^{40}$Ar and a sterile neutrino oscillation study
• Chiral Analysis of the Nucleon Mass and Sigma Commutator
• Strange Vector Form Factor of Kaons
• Probing the structure of Nucleons in Electromagbetic Interactions
• Early Results from the Qweak Experiment
• Parity Violation with Electrons and Hadrons
• Q-weak: First Direct Measurement of the Weak Charge of the Proton