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Articles 61 - 75 of 75

Full-Text Articles in Physical Sciences and Mathematics

Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration Jan 2002

Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

Differential cross sections for γp→ηp have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W = 1.75  GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S11 resonance with mass ∼1.8  GeV couples to the ηN channel.

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Publisher's Note: Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev [Phys. Rev. Lett. 89, 222002 (2002)], M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration Jan 2002

Publisher's Note: Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev [Phys. Rev. Lett. 89, 222002 (2002)], M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, S. Stepanyan, L. B. Weinstein, Et Al., Clas Collaboration

Physics Faculty Publications

No abstract provided.

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Electroproduction Of The Λ(1520) Hyperon, M. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, Et Al., The Clas Collaboration Jan 2001

Electroproduction Of The Λ(1520) Hyperon, M. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, S. E. Kuhn, R. A. Niyazov, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

The reaction e→pe′K+Λ(1520) with Λ(1520)→p′K− was studied at electron beam energies of 4.05, 4.25, and 4.46 GeV, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cos θK+, φK+, Q2, and W dependencies of Λ(1520) electroproduction are presented for the kinematic region 0.9 < Q2 < 2.4 GeV2 and 1.95 < W < 2.65 GeV. Also, the Q2 dependence of the Λ(1520) decay angular distribution is presented for the first time. The cosθK+ angular distributions suggest t-channel diagrams dominate the production process. Fits to the Λ(1520) t-channel helicity frame decay angular distributions indicate the m …

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The Ep → E'P Η Reaction At And Above The S₁₁ (1535) Baryon Resonance, R. Thompson, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, Et Al., The Clas Collaboration Jan 2001

The Ep → E'P Η Reaction At And Above The S₁₁ (1535) Baryon Resonance, R. Thompson, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, Et Al., The Clas Collaboration

Physics Faculty Publications

New cross sections for the reaction ep → ep η are reported for total center of mass energy W = 1.5-1.86 GeV and invariant momentum transfer Q2 = 0.25-1.5 (GeV/c)2. This large kinematic range allows extraction of important new information about response functions, photocouplings, and etaN coupling strengths of baryon resonances. Newly observed structure at W ~ 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance.

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Renormalons As Dilation Modes In The Functional Space, A. Babansky, I. Balitsky Jan 2000

Renormalons As Dilation Modes In The Functional Space, A. Babansky, I. Balitsky

Physics Faculty Publications

There are two possible sources of the factorial large-order behavior of a typical perturbative series. First, the number of different Feynman diagrams may be large; second, there may be abnormally large diagrams known as renormalons. It is well known that the large combinatorial number of diagrams is described by instanton-type solutions of the classical equations. We demonstrate that, from the functional-integral viewpoint, the renormalons do not correspond to a particular configuration but manifest themselves as dilatation modes in the functional space.

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Deeply Virtual Compton Scattering At Small X, Ian Balitsky, Elena Kuchina Jan 2000

Deeply Virtual Compton Scattering At Small X, Ian Balitsky, Elena Kuchina

Physics Faculty Publications

We calculate the cross section of deeply virtual Compton scattering at large energies and intermediate momentum transfers.

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A First Principles Warm Inflation Model That Solves The Cosmological Horizon And Flatness Problems, Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos Jul 1999

A First Principles Warm Inflation Model That Solves The Cosmological Horizon And Flatness Problems, Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos

Dartmouth Scholarship

A quantum field theory warm inflation model is presented that solves the horizon and flatness problems. The model obtains, from the elementary dynamics of particle physics, cosmological scale factor trajectories that begin in a radiation dominated regime, enter an inflationary regime, and then smoothly exit back into a radiation dominated regime, with non-negligible radiation throughout the evolution.

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Strong Dissipative Behavior In Quantum Field Theory, Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos Nov 1998

Strong Dissipative Behavior In Quantum Field Theory, Arjun Berera, Marcelo Gleiser, Rudnei O. Ramos

Dartmouth Scholarship

We study the conditions under which an overdamped regime can be attained in the dynamic evolution of a quantum field configuration. Using a real-time formulation of finite temperature field theory, we compute the effective evolution equation of a scalar field configuration, quadratically interacting with a given set of other scalar fields. We then show that, in the overdamped regime, the dissipative kernel in the field equation of motion is closely related to the shear viscosity coefficient, as computed in scalar field theory at finite temperature. The effective dynamics is equivalent to a time-dependent Ginzburg-Landau description of the approach to equilibrium …

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Factorization For High-Energy Scattering, Ian Balitsky Jan 1998

Factorization For High-Energy Scattering, Ian Balitsky

Physics Faculty Publications

I demonstrate that the amplitude for the high-energy scattering can be factorized into a product of two independent functional integrals over “fast” and “slow” fields which interact by means of Wilson-line operators—gauge factors ordered along the straight lines.

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How Much Of The Nucleon Spin Is Carried By Glue?, Ian Balitsky, Xiangdong Ji Jan 1997

How Much Of The Nucleon Spin Is Carried By Glue?, Ian Balitsky, Xiangdong Ji

Physics Faculty Publications

We estimate in the QCD sum rule approach the amount of the nucleon spin carried by the gluon angular momentum: the sum of the gluon spin and orbital angular momenta. The result indicates that gluons contribute at least one half of the nucleon spin at the scale of 1GeV2.

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Deep Inelastic Scattering Of Polarized Electrons By Polarized ³He And The Study Of The Neutron Spin Structure, P. L. Anthony, R. G. Arnold, H. R. Band, H. Borel, P. E. Bosted, V. Breton, G. D. Cates, T. E. Chupp, F. S. Dietrich, J. Dunne, R. Erbacher, J. Felbauum, H. Fonvielle, R. Gearhart, R. Holmes, E. W. Hughes, J. R. Johnson, D. Kawall, C. Keppel, S. E. Kuhn, R. M. Lombard-Nelsen, J. Marroncle, T. Maruyama, W. Meyer, Z.- E. Meziani, H. Middleton, J. Morgenstern, N. R. Newbury, G. G. Petratos, R Pitthan, R. Prepost, Y. Robin, S. E. Rock, S. H. Rokni, G. Shapiro, T. Smith, P. A. Souder, M. Spengos, F. Staley, L. M. Stuart, Z. M. Szlata, Y. Terrien, A. K. Thompson, J. L. White, M. Woods, J. Xu, C. C. Young, G. Zaplac, E142 Collaboration Jan 1996

Deep Inelastic Scattering Of Polarized Electrons By Polarized ³He And The Study Of The Neutron Spin Structure, P. L. Anthony, R. G. Arnold, H. R. Band, H. Borel, P. E. Bosted, V. Breton, G. D. Cates, T. E. Chupp, F. S. Dietrich, J. Dunne, R. Erbacher, J. Felbauum, H. Fonvielle, R. Gearhart, R. Holmes, E. W. Hughes, J. R. Johnson, D. Kawall, C. Keppel, S. E. Kuhn, R. M. Lombard-Nelsen, J. Marroncle, T. Maruyama, W. Meyer, Z.- E. Meziani, H. Middleton, J. Morgenstern, N. R. Newbury, G. G. Petratos, R Pitthan, R. Prepost, Y. Robin, S. E. Rock, S. H. Rokni, G. Shapiro, T. Smith, P. A. Souder, M. Spengos, F. Staley, L. M. Stuart, Z. M. Szlata, Y. Terrien, A. K. Thompson, J. L. White, M. Woods, J. Xu, C. C. Young, G. Zaplac, E142 Collaboration

Physics Faculty Publications

The neutron longitudinal and transverse asymmetries A1n and A2n have been extracted from deep inelastic scattering of polarized electrons by a polarized 3He target at incident energies of 19.42, 22.66, and 25.51 GeV. The measurement allows for the determination of the neutron spin structure functions g1n (x,Q2) and g2n(x,Q2) over the range 0.032 of 2 (GeV/c)2. The data are used for the evaluation of the Ellis-Jaffe and Bjorken sum rules. The neutron spin structure function g1n(x,Q2) is small and …

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Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman Jan 1996

Inclusive Electron Scattering From Nuclei At X≃1, J. Arrington, P. Anthony, R. G. Arnold, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, W. Lorenzon, A. Lung, N.C.R. Malkins, D. J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, T.G. O'Neill, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, D. Winter, B. Zeidman

Physics Faculty Publications

The inclusive A(e,e') cross section for x≃1 was measured on 2H, C, Fe, and Au for momentum transfers Q2 from 1 to 6.8 (GeV/c)2. The scaling behavior of the data was examined in the region of transition from y scaling to x scaling. Throughout this transitional region, the data exhibit ξ scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.

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Two-Body Photodisintegration Of The Deuteron Up To 2.8 Gev, J. E. Belz, D. H. Potterveld, S. E. Kuhn, J.F. J. Van Den Brand, J. L. White, B. Zeidman, Et Al. Jan 1995

Two-Body Photodisintegration Of The Deuteron Up To 2.8 Gev, J. E. Belz, D. H. Potterveld, S. E. Kuhn, J.F. J. Van Den Brand, J. L. White, B. Zeidman, Et Al.

Physics Faculty Publications

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.

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A-Dependence Of Nuclear Transparency In Quasielastic A (E, E'P) At High Q², T. G. O'Neill, W. Lorenzon, P. Anthony, R. G. Arnold, J. Arrington, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, A. Lung, N.C.R. Makins, D.J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, B. Zeidman Jan 1995

A-Dependence Of Nuclear Transparency In Quasielastic A (E, E'P) At High Q², T. G. O'Neill, W. Lorenzon, P. Anthony, R. G. Arnold, J. Arrington, E. J. Beise, J. E. Belz, P. E. Bosted, H.- J. Bulten, M. S. Chapman, K. P. Coulter, F. Dietrich, R. Ent, M. Epstein, B. W. Filippone, H. Gao, R. A. Gearhart, D. F. Geesaman, J.- O. Hansen, R. J. Holt, H. E. Jackson, C. E. Jones, C. E. Keppel, E. R. Kinney, S. Kuhn, K. Lee, A. Lung, N.C.R. Makins, D.J. Margaziotis, R. D. Mckeown, R. G. Milner, B. Mueller, J. Napolitano, J. Nelson, V. Papavassiliou, G. G. Petratos, D. H. Potterveld, S. E. Rock, M. Spengos, Z. M. Szalata, L. H. Tao, K. Van Bibber, J.F.J. Van Den Brand, J. L. White, B. Zeidman

Physics Faculty Publications

The A-dependence of the quasielastic A(e, ef'p) reaction has been studied at SLAC with 2H, C, Fe, and Au nuclei at momentum transfers Q2 = 1, 3, 5, and 6.8 (GeV/c)2. We extract the nuclear transparency T(A, Q2), a measure of the average probability that the struck proton escapes from the nucleus A without interaction. Several calculations predict a significant increase in T with momentum transfer, a phenomenon known as Color Transparency. Within the measurement uncertainty, no increase is seen for any of the nuclei studied.

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Energetic Protons And Deuterons Emitted Following Μ⁻ Capture By ³He Nuclei, W. J. Cummings, G. E. Dodge, S. S. Hanna, B. H. King, S. E. Kuhn, Y. M. Shin, R. Helmer, R. B. Schubank, N. R. Stevenson, U. Wienands, Y. K. Lee, G. R. Mason, B. E. King, K. S. Chung, J. M. Lee, D. P. Rosenzweig Jan 1992

Energetic Protons And Deuterons Emitted Following Μ⁻ Capture By ³He Nuclei, W. J. Cummings, G. E. Dodge, S. S. Hanna, B. H. King, S. E. Kuhn, Y. M. Shin, R. Helmer, R. B. Schubank, N. R. Stevenson, U. Wienands, Y. K. Lee, G. R. Mason, B. E. King, K. S. Chung, J. M. Lee, D. P. Rosenzweig

Physics Faculty Publications

Spectra of energetic protons and deuterons emitted following negative muon capture from rest in 3He have been measured for the first time. Significant capture strength is observed at high energy transfers (mμ- Ev >60 MeV) for the two-body and three-body breakup channels, indicative of the importance of nucleon-nucleon correlations and meson exchange currents in the capture process. A simple plane wave impulse approximation calculation reproduces the proton spectrum reasonably well, but underpredicts the deuteron rate at the highest energies by a large factor.

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