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We present the first measurements of the e[over -->]p-->epgamma cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q(2) dependence (from 1.5 to 2.3 GeV(2)) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to(More)
We propose to measure the parity-violating electroweak asymmetry A P V in the deep-inelastic scattering of polarized electrons (PVDIS) to high precision in order to search for physics beyond the Standard Model in lepton-quark neutral current interactions. Presently, the atomic parity-violation measurement in 133 Cs provides important limits on such new(More)
The upgraded 11 GeV CEBAF polarized electron beam presents a compelling opportunity to measure a weak neutral current amplitude to unprecedented precision at Q 2 M 2 Z. The result would yield a precise measurement of the weak mixing angle sin 2 θ W , a fundamental parameter of the electroweak theory. The experimental goal of δ(sin 2 θ W) ∼ 0.1%, matching(More)
The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical(More)
Beam-helicity asymmetries for the two-pion-photoproduction reaction gammap-->ppi(+)pi(-) have been studied for the first time in the resonance region for center-of-mass energies between 1.35 and 2.30 GeV. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an(More)
We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) +/- 10(syst)] x 10(-9), leading to the determination of the weak mixing angle sin2(thetaW(eff) = 0.2397 +/- 0.0010(stat) +/- 0.0008(syst), evaluated at Q2 = 0.026 GeV2. Combining this result with the(More)
The ratio of the proton's elastic electromagnetic form factors, G Ep ͞G Mp , was obtained by measuring P t and P ᐉ , the transverse and the longitudinal recoil proton polarization, respectively. For elastic ៬ ep ! e ៬ p, G Ep ͞G Mp is proportional to P t ͞P ᐉ. Simultaneous measurement of P t and P ᐉ in a polarimeter provides good control of the systematic(More)
The longitudinal target-spin asymmetry AUL for the exclusive electroproduction of high-energy photons was measured for the first time in ep-->e;'pgamma. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from(More)
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from protons. Significant contributions to this asymmetry could arise from the contributions of strange form factors in the nucleon. The measured asymmetry is A = −15.05 ± 0.98(stat) ± 0.56(syst) ppm at the kinematic point θ lab = 12.3 • and Q 2 =(More)