[en] Beam Single Spin Asymmetries in single neutral semi-inclusive pion electroproduction off an unpolarized hydrogen target in the deep inelastic scattering regime (Q²>1 GeV², W²>4 GeV²) have been measured using a polarized electron beam of 5.776 GeV with the CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Accelerator Facility (JLab). The measured kinematical dependences are compared with published data and existing theoretical predictions.

[en] The Center for the Advancement of Natural Discoveries using Light Emission (CANDLE) is a 3 GeV intermediate energy light source project in Armenia. The paper presents the study and design futures of the first group of beamlines that are planed to run among with the facility operation scheduled for year 2007. Presented beamlines will cover the experimental researches based on diffraction and powder diffraction, XAS, Soft X-ray spectroscopy and microscopy, Small angle X-ray scattering, X-ray Imaging techniques and LIGA

[en] We present studies of double longitudinal spin asymmetries in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator, which includes quark intrinsic transverse momentum within the generalized parton model based on the fully differential cross section for the process. Additionally we employ Bessel-weighting to the MC events to extract transverse momentum dependent parton distribution functions and also discuss possible uncertainties due to kinematic correlation effects.

[en] We present studies of double longitudinal spin asymmetries in semiinclusive deep inelastic scattering using a new dedicated Monte Carlo generator, which includes quark intrinsic transverse momentum within the generalized parton model based on the fully differential cross section for the process. Additionally, we apply Bessel-weighting to the simulated events to extract transverse momentum dependent parton distribution functions and also discuss possible uncertainties due to kinematic correlation effects.

[en] The influence of cold nuclear matter on lepto-production of hadrons in semi-inclusive deep inelastic scattering is measured using the CLAS detector in Hall B at Jefferson Lab and a 5.014 GeV electron beam. We report the View the MathML source multiplicity ratios for targets of C, Fe, and Pb relative to deuterium as a function of the fractional virtual photon energy z transferred to the View the MathML source and the transverse momentum squared View the MathML source of the View the MathML source. We find that the multiplicity ratios for View the MathML source are reduced in the nuclear medium at high z and low View the MathML source, with a trend for the View the MathML source transverse momentum to be broadened in the nucleus for large View the MathML source.

[en] A detailed X-ray Absorption Spectroscopic examination of S-Au interaction in gold nanoparticle bound to Polystyrene-Divinyl Benzene (PS-DVB) micro beads was carried out. Gold nanoparticles were bound to the surface of the commercially available PS-DVB beads using a simple one step procedure. Influence of polystyrene backbone on the electronic structure of the gold nanoparticles was observed through X-ray Absorption Near Edge Structure (XANES) spectra of Au at L III edge. An additional structure in the white line of the S K-edge XANES spectrum confirmed the presence of S-Au bonding. Transmission Electron Microscopy (TEM) studies coupled with Selected Area Electron Diffraction Pattern and X-ray Diffraction studies revealed the morphology of the Au nanoparticles bound to the micro beads

[en] High-statistics measurements of differential cross sections and recoil polarizations for the reaction γp→K⁺Σ⁰ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√(s)) from 1.69 to 2.84 GeV, with an extensive coverage in the K⁺ production angle. Independent measurements were made using the K⁺pπ^-(γ) and K⁺p(π^-,γ) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR, and LEPS results, while offering better statistical precision and a 300-MeV increase in √(s) coverage. Above √(s)≅2.5 GeV, t- and u-channel Regge scaling behavior can be seen at forward and backward angles, respectively. Our recoil polarization (P_Σ) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles, we find that P_Σ is of the same order of magnitude but opposite sign as P_Λ, in agreement with the static SU(6) quark model prediction of P_Σ≅-P_Λ. This expectation is violated in some mid- and backward-angle kinematic regimes, where P_Σ and P_Λ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial-wave analyses being performed to search for missing baryon resonances.

[en] The electromagnetic decay Σ⁰(1385)→Λγ was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility. A real photon beam with a maximum energy of 3.8 GeV was incident on a proton target, producing an exclusive final state of K⁺Σ^*0. We report the decay widths ratio Σ⁰(1385)→Λγ/Σ⁰(1385)→Λπ⁰=1.42±0.12(stat)_-0.07^+0.11(sys)%. This ratio is larger than most theoretical predictions by factors ranging from 1.5-3, but is consistent with the only other experimental measurement. From the reported ratio we calculate the partial width and electromagnetic transition magnetic moment for Σ⁰(1385)→Λγ.

[en] In this paper we present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy/Q2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs

[en] We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sinφ_h amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle φ_h of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.