Alexandre Deur

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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)
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)
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 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)
We propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep → epγ in Hall A at Jefferson Lab with a 6 GeV beam. We are able to explore the onset of Q 2 scaling, by measuring a beam helicity asymmetry for Q 2 ranging from 1.5 to 2.5 GeV 2 at xB ≈ 0.35. At this kinematics, the asymmetry is dominated by the DVCS-Bethe-Heitler (BH)(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)
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)
Weinstein) is actively involved in this proposal, as well as two other proposal using CLAS12. Other members of our group are pursuing a proposal for Hall A, but their contributions are not included here. Among CLAS12 baseline equipment, the group intends to take responsibility for the design, prototyping, construction and testing of the Region 1 Drift(More)
A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6 GeV electron beam, a longitudinally polarized proton target, and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for ep→e^{'}p^{'}γ events, which arise from the interference of the deeply virtual(More)