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Old Dominion University

Physics Faculty Publications

Series

2008

Articles 1 - 15 of 15

Full-Text Articles in Physics

3he Spin-Dependent Cross Sections And Sum Rules, K. Slifer, M. Amarian, L. Auerbach, T. Averett, J. Berthot, P. Bertin, B. Bertozzi, K. Mccormick, F. Sabatié, L. Todor Jul 2008

3he Spin-Dependent Cross Sections And Sum Rules, K. Slifer, M. Amarian, L. Auerbach, T. Averett, J. Berthot, P. Bertin, B. Bertozzi, K. Mccormick, F. Sabatié, L. Todor

Physics Faculty Publications

We present a measurement of the spin-dependent cross sections for the 3→He(→e,e′)X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1≤Q2≤0.9  GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

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Investigation Of Loading Of Pulsed And Continuous-Wave Optical Dipole Force Traps, M. Shiddiq, E. M. Ahmed, M. D. Havey, C. I. Sukenik Apr 2008

Investigation Of Loading Of Pulsed And Continuous-Wave Optical Dipole Force Traps, M. Shiddiq, E. M. Ahmed, M. D. Havey, C. I. Sukenik

Physics Faculty Publications

We have investigated the behavior of an optical dipole force trap realized using a mode-locked Nd:YAG laser and have compared performance to a continuous-wave (cw) trap built using the same laser but running in a cw mode. The traps are used to confine ultracold 85Rb atoms which are loaded from a magneto-optical trap (MOT). In most respects, the two traps behave similarly over a wide range of laser parameters provided that the average potential well depth is the same; however, there is a notable difference in the dipole trap loading efficiency dependence on the detuning of the MOT trap laser …

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Extended Tuning Of An Injection-Locked Diode Laser, M. K. Shaffer, G. Ranjit, C. I. Sukenik Apr 2008

Extended Tuning Of An Injection-Locked Diode Laser, M. K. Shaffer, G. Ranjit, C. I. Sukenik

Physics Faculty Publications

We have investigated the application of an electronic feedback technique recently reported by Repasky, et.al. [Appl. Opt. 45, 9013 (2006)] to an injection-locked semiconductor diode laser. We find that without electronic feedback, the injection-locked slave laser will only follow the master for less than 1 GHz, but once the electronic feedback is applied, the slave laser is capable of following for more than 20 GHz, corresponding to the full scan range of the master laser.

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Ratios Of 15N/12C And 4He/12C Inclusive Electroproduction Cross Sections In The Nucleon Resonance Region, P. E. Bosted, R. Fersch, G. Adams, M. Amaryan, S. Anefalos, M. Anghinolfi, G. Asryan, H. Avakian, H. Badasaryan, N. Baillie, M. Bektasoglu, S. Bültmann, S. L. Careccia, G. E. Dodge, K. V. Dharmawardane, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, R. A. Niyazov, L. M. Qin, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Clas Collaboration Jan 2008

Ratios Of 15N/12C And 4He/12C Inclusive Electroproduction Cross Sections In The Nucleon Resonance Region, P. E. Bosted, R. Fersch, G. Adams, M. Amaryan, S. Anefalos, M. Anghinolfi, G. Asryan, H. Avakian, H. Badasaryan, N. Baillie, M. Bektasoglu, S. Bültmann, S. L. Careccia, G. E. Dodge, K. V. Dharmawardane, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, S. E. Kuhn, J. Lachniet, R. A. Niyazov, L. M. Qin, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Clas Collaboration

Physics Faculty Publications

The (W,Q2) dependence of the ratio of inclusive electron scattering cross sections for 15N/12C was determined in the kinematic ranges 0.8 < W < 2 GeV and 0.2 < Q2 < 1 GeV2 using 2.285 GeV electrons and the CLAS detector at Jefferson Lab. The ratios exhibit only slight resonance structure, in agreement with a simple phenomenological model and an extrapolation of deep-inelastic scattering ratios to low Q2. Ratios of 4He/12C using 1.6 to 2.5 GeV electrons were measured with very high statistical precision and were used to correct for He in the N and C targets. …

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Next-To-Leading Order Evolution Of Color Dipoles, Ian Balitsky, Giovanni A. Chirilli Jan 2008

Next-To-Leading Order Evolution Of Color Dipoles, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

The small-x deep inelastic scattering in the saturation region is governed by the nonlinear evolution of Wilson-line operators. In the leading logarithmic approximation it is given by the Balitsky-Kovchegov equation for the evolution of color dipoles. In the next-to-leading order the Balitsky-Kovchegov equation gets contributions from quark and gluon loops as well as from the tree gluon diagrams with quadratic and cubic nonlinearities. We calculate the gluon contribution to the small-x evolution of Wilson lines (the quark part was obtained earlier).

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Advances On Elic Design Studies, S. A. Bogacz, P. Chevtsov, Ya. Derbenev, P. Evtushenko, G. Krafft, A. Hutton, R. Li, L. Merminga, J. Musson, B. Yunn, Y. Zhang, H. Sayed Jan 2008

Advances On Elic Design Studies, S. A. Bogacz, P. Chevtsov, Ya. Derbenev, P. Evtushenko, G. Krafft, A. Hutton, R. Li, L. Merminga, J. Musson, B. Yunn, Y. Zhang, H. Sayed

Physics Faculty Publications

An electron-ion collider of a center-of-mass energy up to 90 GeV at luminosity up to 1035 cm-2s-1 with both beams highly polarized is essential for exploring the new QCD frontier of strong color fields in nuclear and precisely imaging the sea-quarks and gluons in the nucleon. A conceptual design of a ring-ring collider based on CEBAF (ELIC) with energies up to 9 GeV for electrons/positrons and up to 225 GeV for protons and 100 GeV/u for ions has been proposed to fulfill the science desire and to serve as the next step for CEBAF after the …

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Light Vector Mesons In The Nuclear Medium, M. H. Wood, M. J. Amaryan, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, H. G. Juengst, N. Kalantarians, A. Klein, K. V. Klimenko, S. E. Kuhn, J. Lachniet, M. R. Niroula, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, J. Zhang, Clas Collaboration Jan 2008

Light Vector Mesons In The Nuclear Medium, M. H. Wood, M. J. Amaryan, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, H. G. Juengst, N. Kalantarians, A. Klein, K. V. Klimenko, S. E. Kuhn, J. Lachniet, M. R. Niroula, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, J. Zhang, Clas Collaboration

Physics Faculty Publications

The light vector mesons (ρ,ω, and ϕ) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the ρ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to e+e−. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The ρ-meson mass spectrum was extracted after the ω and ϕ signals were removed in a nearly model-independent way. Comparisons …

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First Measurement Of Target And Double Spin Asymmetries For Ep → Epπ° In The Nucleon Resonance Region Above The Δ (1232), Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, G. E. Dodge, N. Guler, N. Kalantarians, A. Klein, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

First Measurement Of Target And Double Spin Asymmetries For Ep → Epπ° In The Nucleon Resonance Region Above The Δ (1232), Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, G. E. Dodge, N. Guler, N. Kalantarians, A. Klein, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The exclusive channel polarized proton(polarized e,e' p)π0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the π0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data …

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Electroproduction Of ɸ(1020) Mesons At 1.4 ≤ Q² ≤ 3.8 Gev² Measured With The Clas Spectrometer, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde-Wright, H. G. Jungst, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, T. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Electroproduction Of ɸ(1020) Mesons At 1.4 ≤ Q² ≤ 3.8 Gev² Measured With The Clas Spectrometer, Clas Collaboration, M. J. Amaryan, H. Bagdasaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde-Wright, H. G. Jungst, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, T. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

Electroproduction of exclusive ϕ vector mesons has been studied with the CLAS detector in the kinematic range 1.4 ⩽ Q2 ⩽ 3.8 GeV2 ,0.0 ⩽ t′ ⩽3.6 GeV2 , and 2.0 ⩽ W ⩽ 3.0 GeV. The scaling exponent for the total cross section as 1/(Q2 +M2ϕ)n was determined to be n = 2.49 ± 0.33. The slope of the four-momentum transfer t′ distribution is bϕ = 0.98 ± 0.17 GeV-2 . Under the assumption of s -channel helicity conservation, we determine the ratio of longitudinal to transverse cross sections …

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Experimental Study Of Isovector Spin Sum Rules, A. Deur, P. Bosted, V. Burkert, D. Crabb, V. Dharmawardane, G. E. Dodge, T. A. Forest, K. A. Griffioen, S. E. Kuhn, R. Minehart, Y. Prok Jan 2008

Experimental Study Of Isovector Spin Sum Rules, A. Deur, P. Bosted, V. Burkert, D. Crabb, V. Dharmawardane, G. E. Dodge, T. A. Forest, K. A. Griffioen, S. E. Kuhn, R. Minehart, Y. Prok

Physics Faculty Publications

We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for 0.05< Q2 2. The integral is fit to extract the twist-4 element f p−n2 which appears to be relatively large and negative. Systematic studies of this higher twist analysis establish its legitimacy at Q2 around 1  GeV2. We also performed an isospin decomposition of the generalized forward spin polarizability γ0. Although its isovector part provides a reliable test of the calculation techniques of chiral perturbation theory, our data disagree with the calculations.

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Measurement Of Deeply Virtual Compton Scattering Beam-Spin Asymmetries, Clas Collaboration, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Measurement Of Deeply Virtual Compton Scattering Beam-Spin Asymmetries, Clas Collaboration, H. Bagdasaryan, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, C. E. Hyde, H. G. Juengst, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (→ep→epγ ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (xB from 0.11 to 0.58, Q2 from 1 to 4.8  GeV2, −t from 0.09 to 1.8  GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A ≃ asinϕ/(1+ccosϕ). This extensive set of data can thus be used to …

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Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang Jan 2008

Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The beam spin asymmetry (BSA) in the exclusive reaction →ep→epπ0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The xB,Q2,t , and ϕ dependences of the π0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sinϕ function and their amplitudes are extracted. Overall, they are of the order of 0.04–0.11 and roughly independent of t . This is the signature of a nonzero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as …

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Cross Sections And Beam Asymmetries For E ⃗ P → Enπ+ In The Nucleon Resonance Region For 1.7 ⩽ Q2 ⩽ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration Jan 2008

Cross Sections And Beam Asymmetries For E ⃗ P → Enπ+ In The Nucleon Resonance Region For 1.7 ⩽ Q2 ⩽ 4.5 Gev2, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klein, A. V. Klimenko, S. E. Kuhn, J. Lachniet, R. A. Niyazov, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

The exclusive electroproduction process e ⃗ p → e'nπ+ was measured in the range of the photon virtuality Q2 =1.7-4.5 GeV2, and the invariant mass range for the n π+ system of W=1.15-1.7 GeV using the CEBAF Large Acceptance Spectrometer. For the first time, these kinematics are probed in exclusive π+ production from protons with nearly full coverage in the azimuthal and polar angles of the nπ+ center-of-mass system. The nπ+ channel has particular sensitivity to the isospin 1/2 excited nucleon states, and together with the pπ0 final state will serve …

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Nlo Evolution Of Color Dipole, Ian Balitsky, Giovanni A. Chirilli Jan 2008

Nlo Evolution Of Color Dipole, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

No abstract provided.

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Electroexcitation Of The Roper Resonance For 1.7 < Q² < 4.5gev² In Ep → Enπ+, Clas Collaboration, M. J. Amaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, L. M. Qin, L. B. Weinstein, J. Yun, J. Zhang Jan 2008

Electroexcitation Of The Roper Resonance For 1.7 < Q² < 4.5gev² In Ep → Enπ+, Clas Collaboration, M. J. Amaryan, M. Bektasoglu, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde, A. Klein, S. E. Kuhn, L. M. Qin, L. B. Weinstein, J. Yun, J. Zhang

Physics Faculty Publications

The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for 1.7 < Q2 < 4.5 GeV2 from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for π+ electroproduction on protons at W=1.15-1.69 GeV. The analysis is made using two approaches, dispersion relations and a unitary isobar model, which give consistent Q2 behavior of the helicity amplitudes for the gamma*p -> N (1440)P11 transition. It is found that the transverse helicity amplitude A 1/2, which is large and negative at Q2=0, becomes large and positive at Q2 similar or equal …

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