Extraction of Beam-Spin Asymmetries from the Hard Exclusive π⁺ Channel Off Protons in a Wide Range of Kinematics

We have measured beam-spin asymmetries to extract the sinϕ moment ALUsinϕ from the hard exclusive e→p → e\u27nπ+ reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The ALUsinϕ moment has been measured up to 6.6  GeV2 in -t, covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found ALUsinϕ to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks

Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

A first measurement of the longitudinal beam spin asymmetry ALU in the semi-inclusive electroproduction of pairs of charged pions is reported. ALU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the AsinLUϕR moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics

Assessing L2 Argumentation in the UAE Context

In this rapidly changing world, argumentation and critical thinking skills are undeniably crucial for new generations of Emirati students. These skills lay the groundwork for a competitive economy, which is a priority for the UAE in its Vision 2021. Specifically, today’s modern workplaces require workers to evaluate different propositions and develop their own after weighing up these various ideas, and thus the ability to defend arguments in English has become increasingly important for UAE university students in English-medium universities as well as their future professional contexts. Despite this importance, research regarding argumentation and the related critical thinking skills is sorely lacking in the UAE. This chapter delineates how written argumentation was assessed in a timed essay in a mandatory argumentative writing course taken by university freshmen in a government university in the UAE, and how the feedback gleaned from this common assessment was mapped to the teaching curriculum to shed light on the teaching effectiveness and to provide directions for future teaching

Two-Body Photodisintegration of the Deuteron up to 2.8 GeV

Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 to 2.8 GeV and center-of-mass angles from 37° to 90°. The measured energy dependence of the cross section at θc.m. = 90° is in agreement with the constituent counting rules

Semi-Inclusive Pi(0) Target and Beam-Target Asymmetries from 6 GeV Electron Scattering with CLAS

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic 14NH3 target, and extracted double and single target spin asymmetries for ep→e′ π0 X in multidimensional bins in four-momentum transfer (1.0 2 \u3c 3.2 GeV2), Bjorken -x (0.12 \u3c x \u3c 0.48), hadron energy fraction (0.4 \u3c z 0.7), tranverse pion meomentum (0 \u3c PT \u3c 1.0 GeV), and azimuthal angle ϕh between the lepton scattering and hadron production planes. We extracted asymmetries as a function of both x and PT, which provides access to transverse-momentum distributions of longitudinally polarized quarks. The double spin asymmetries depend weakly on PT. The sin 2ϕh moments are zero within uncertainties, which is consistent with the expected suppression of the Collins fragmentation function. The observed sin ϕh moments suggest that quark gluon correlations are significant at large x

Beam-Spin Asymmetries From Semi-Inclusive Pion Electroproduction

We have measured the moment Asin ɸLU corresponding to the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering. Asin ɸLU is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels (π+,π0 and π-) were measured simultaneously over a large range of kinematics within the virtuality range Q2 ≈ 1.0- 4.5 GeV2. The observable was measured with better than 1% statistical precision over a large range of z, PT, xB, and Q2, which permits comparison with several reaction models. The discussed measurements provide an upgrade in statistics over previous measurements, and serve as the first evidence for the negative sign of the π- sin ɸ moment