8 research outputs found

    Target and double spin asymmetries of deeply virtual pi(0) production with a longitudinally polarized proton target and CLAS

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    The target and double spin asymmetries of the exclusive pseudoscalar channel epepπ0\vec e\vec p\to ep\pi^0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2Q^2, xBx_B, t-t and ϕ\phi. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs H~T\tilde{H}_T and ETE_T, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HTH_T and EˉT\bar E_T. These data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models

    First measurement of the polarization observable E in the p→(γ→,π<sup>+</sup>)n reaction up to 2.25 GeV

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    First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction γpπ+n\vec \gamma \vec p \to \pi^+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, J\"ulich, and SAID groups.Comment: 6 pages, 3 figure

    Semi-inclusive pi(0) target and beam-target asymmetries from 6 GeV electron scattering with CLAS

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    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 14^{14}NH3_3 target, and extracted double and single target spin asymmetries for epeπ0Xep\rightarrow e^\prime\pi^0X in multidimensional bins in four-momentum transfer (1.0<Q2<3.21.0<Q^2<3.2 GeV2^2), Bjorken-xx (0.12<x<0.480.12<x<0.48), hadron energy fraction (0.4<z<0.70.4<z<0.7), transverse pion momentum (0<PT<1.00<P_T<1.0 GeV), and azimuthal angle ϕh\phi_h between the lepton scattering and hadron production planes. We extracted asymmetries as a function of both xx and PTP_T, which provide access to transverse-momentum distributions of longitudinally polarized quarks. The double spin asymmetries depend weakly on PTP_T. The sin2ϕh\sin 2\phi_h moments are zero within uncertainties, which is consistent with the expected suppression of the Collins fragmentation function. The observed sinϕh\sin\phi_h moments suggest that quark gluon correlations are significant at large xx.Comment: 18 preprint pages, 3 figure

    Proposal for a candidate core set of fitness and strength tests for patients with childhood or adult idiopathic inflammatory myopathies

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    OBJECTIVE: Currently there are no evidence-based recommendations regarding fitness and strength tests for patients with childhood or adult idiopathic inflammatory myopathies (IIM). This hinders clinicians and researchers in choosing the appropriate fitness- or muscle strength-related outcome measures for these patients. Through a Delphi survey, we aimed to identify a candidate core set of fitness and strength tests for children and adults with IIM. METHODS: Fifteen experts participated in a Delphi survey that consisted of 5 stages to achieve a consensus. Using an extensive search of published literature and through the work of experts, a candidate core set based on expert opinion and clinimetrics properties was developed. Members of the International Myositis Assessment and Clinical Studies Group were invited to review this candidate core set during the final stage, which led to a final candidate core set. RESULTS: A core set of fitness- and strength-related outcome measures was identified for children and adults with IIM. For both children and adults, different tests were identified and selected for maximal aerobic fitness, submaximal aerobic fitness, anaerobic fitness, muscle strength tests, and muscle function tests. CONCLUSION: The core set of fitness- and strength-related outcome measures provided by this expert consensus process will assist practitioners and researchers in deciding which tests to use in patients with IIM. This will improve the uniformity of fitness and strength tests across studies, thereby facilitating the comparison of study results and therapeutic exercise program outcomes among patients with IIM

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