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1. The G0 experiment: Parity violation in e-N elastic scattering

Author: P. G. Roos
Subjects: Nuclear physics, Elastic scattering, Physics, Quark, Nuclear and High Energy Physics, Particle physics, Scattering, Momentum transfer, Hadron, Compton scattering, Parity (physics), Nuclear Experiment, Nucleon
Abstract: The G0 experiment will measure the parity-violating asymmetries in elastic electron-nucleon scattering. The experiment is being performed in Hall C at the Jefferson Laboratory using a polarized electron beam and a dedicated experimental setup. Measurements of the electron-proton asymmetries will be made at both forward and backward angles, and electron-deuteron asymmetries at the backward angles. These measurements will cover a momentum transfer range of 0.1 – 1.0 GeV2/c2. ?From these data the vector neutral weak form factors, G E Z and G M Z , and the effective axial current of the nucleon, G A e , may be extracted. When combined with the known electromagnetic form factors, one will be able to extract the contributions of u, d, and s quarks to the proton’s charge and magnetization distributions. The first measurements at forward angles for the full momentum transfer range have very recently been successfully completed and preliminary results are presented here.
Published: 2005
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2. Electroproduction of kaons on light nuclei

Author: R. Sawafta, J. H. Liu, John C. Mitchell, T. Eden, C. Yan, D. G. Meekins, E. Christy, F. Dohrmann, P. Ambrozewicz, L. Cole, M. Sarsour, A. Ahmidouch, Y. Sato, P. E. Reimer, S. Tajima, J. A. Dunne, J. Roche, S. Danagoulian, Kevin Bailey, B. Mueller, J. W. Price, W. Hinton, N. S. Chant, H. Mkrtchyan, J. Crowder, H. Juengst, Haiyan Gao, John Arrington, G. Savage, C. Cothran, J. P. Schiffer, B. Zihlmann, M. Zeier, H. C. Fenker, J.-O. Hansen, Paul Gueye, Rolf Ent, R. D. Carlini, Brian Raue, R. Asaturyan, L. Gan, W. J. Cummings, A. Semenov, D. F. Geesaman, J. Cha, D. S. Brown, M. Elaasar, A. Cochran, H. Breuer, Dipangkar Dutta, Pete Markowitz, L. Yuan, J. Reinhold, H. Bitao, A. Uzzle, K. Gustafsson, B. Terburg, F. Duncan, S. Stepanyan, P. G. Roos, Ketevi Assamagan, Avraham Klein, G. Collins, Thomas O'Neill, D. Potterveld, V. Tadevosian, K. Garrow, H. E. Jackson, D. Koltenuk, C. S. Armstrong, Y. Liang, O. K. Baker, I. Niculescu, B. Zeidman, A. F. Lung, G. Niculescu, Toshinobu Miyoshi, H. Yamaguchi, R. Madey, D. Abbott, L. Ewell, H. T. Fortune, Y. Fujii, K. Hafidi, R. E. Segel, S. Beedoe, S. Mtingwa, C. J. Martoff, R. Mohring, C. E. Keppel, S. A. Wood, D. J. Mack, Stephen Avery, and L. G. Tang
Subjects: Physics, Nuclear and High Energy Physics, Meson, Proton, Helium-3, Hadron, Production (computer science), Elementary particle, Atomic physics, Nuclear Experiment, Lambda, Isotopes of helium
Abstract: The A(e,e{prime}K{sup +})YX reaction on H, D, {sup 3}He, and {sup 4}He was investigated in Hall C at CEBAF. Data were obtained for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at 3.245 GeV. The missing mass spectra for both H and D are fitted with Monte-Carlo simulations incorporating peaks corresponding to {Lambda} production on the proton and {Sigma} production on both the proton and neutron. For D, the cross section ratio {Sigma}{sup 0}/{Sigma}{sup {minus}} {approx} 2, and excess yield close to the thresholds for {Lambda} and {Sigma} production can be attributed to final-state interactions that are compared to the data. The analysis of the data for the He targets is in a more preliminary state with broader quasi-free peaks resulting from the higher Fermi momenta. Evidence for bound {Lambda}-hypernuclear states is seen and other structure may be present.
Published: 2001
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3. A neutron detector for (p,np) coincidence studies

Author: G. M. Huber, B.C. Markham, Daniel S. Carman, A. Klyachko, A. Eads, P. Schwandt, K. Solberg, L. C. Bland, N. S. Chant, P. G. Roos, J. Huffman, and T. Gu
Subjects: Elastic scattering, Physics, Bonner sphere, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Nuclear Theory, Detector, Particle detector, Neutron time-of-flight scattering, Nuclear physics, Scintillation counter, Neutron detection, Neutron, Nuclear Experiment, Instrumentation
Abstract: A neutron detector with moderate energy resolution (∼3 MeV) has been built for neutrons in the energy range 75–175 MeV. The detector was designed for coincidence scattering experiments. The design eliminates the need for long neutron flight paths necessary for comparable energy resolution time-of-flight measurements with a comparable efficiency-solid angle product (0.02 msr). The detector consists of thin plastic scintillators in which the neutron undergoes n–p elastic scattering. The second-scattered protons are tracked by drift chambers and detected in a sodium iodide array. The design motivations and features are presented along with results from detailed in-beam experimental tests.
Published: 1999
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4. Tensor polarization in elastic electron-deuteron scattering to the highest possible momentum transfers

Author: S. A. Wood, S. Stepanyan, John C. Mitchell, D. J. Mack, R. D. Carlini, S. Mtingwa, R. Mohring, Justin I. McIntyre, A. F. Lung, J. Ball, L. M. Qin, W. Boeglin, H. Breuer, H. Mrktchyan, H. Anklin, Christophe Furget, J.E. Ducret, Paul Gueye, S. Kox, K. Gustafsson, L. Lu, Charles Glashausser, W. Turchinetz, S. Beedoe, G. J. Kumbartzki, D. Abbott, W. Schmidt, P. Rutt, J. A. Dunne, S. Danagoulian, N. S. Chant, E. Tomasi-Gustafsson, A. Ahmidouch, K. Vansyoc, J. Zhao, E. Voutier, P. G. Roos, K. A. Dow, W. Zhao, F. Merchez, A. Honegger, M. Garçon, D. Pitz, Ronald Gilman, J. Volmer, J. Jourdan, W. F. Vulcan, E.J. Stephenson, R. Sawafta, L. Eyraud, C. Yan, J. Arvieux, L. Ewell, Raphael Noel Tieulent, K. Hafidi, Pete Markowitz, J. S. Real, Ronald Ransome, D. G. Meekins, L. Bimbot, E. J. Beise, and C. Williamson
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Scattering, Momentum transfer, Elastic electron, Perturbative QCD, Polarimeter, Polarization (waves), Nuclear physics, Recoil, Deuterium, High Energy Physics::Experiment, Nuclear Experiment
Abstract: In elastic electron-deuteron scattering, the tensor polarization moments t 20 , t 21 and t 22 , together with the unpolarized cross-sections, have been measured up to a momentum transfer of 1.8 (GeV/c) 2 , or 6.8 fm −1 . The experiment was performed at Jefferson Laboratory using the recoil deuteron polarimeter POLDER. Preliminary results are presented and discussed, especially in view of their significance concerning the applicability of perturbative QCD to this exclusive process.
Published: 1999
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5. Quasifree inclusive and exclusive analyzing powers at 200 MeV

Author: J. Huffman, Daniel S. Carman, P. Schwandt, L. C. Bland, G. M. Huber, P. G. Roos, T. Gu, N. S. Chant, K. Solberg, B.C. Markham, and A. Klyachko
Subjects: Nuclear physics, Mass number, Physics, Nuclear and High Energy Physics, Angular range, Particle physics, Isovector, Scattering, Impulse (physics), Spectral line
Abstract: Analyzing power measurements for both inclusive (pW ,p8) and exclusive (pW ,2p) and (pW ,np) quasifree scattering at 200 MeV from H and C have been completed in the angular range from 27° to 34°. Previous experimental and theoretical work has indicated non-negligible suppression of the inclusive (pW ,p8) analyzing powers with respect to impulse approximation calculations. Conversely, both suppression and enhancement of the isovector (pW ,n) analyzing power data have been found depending on the mass number of the target. Both nonrelativistic and fully relativistic calculations have sought to explain these features. However to address such questions within the inclusive data, it is important to fully understand the makeup of the inclusive spectra. This ensures that any ‘‘nonconventional’’ aspects of the data do not arise from contamination of the quasifree scattering yield. @S0556-2813~99!01004-3#
Published: 1999
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6. Quasifree inclusive and exclusive cross sections at 200 MeV

Author: P. Schwandt, P. G. Roos, N. S. Chant, A. Klyachko, J. Huffman, G. M. Huber, B.C. Markham, K. Solberg, L. C. Bland, Daniel S. Carman, and T. Gu
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Reaction dynamics, Scattering, Yield (chemistry), Atomic physics
Abstract: Cross section measurements for both inclusive (p,p′) and exclusive (p,2p) and (p,np) quasifree scattering at 200 MeV from 2 H and 12 C have been completed from 27° to 34°. Inter-comparisons of these inclusive and exclusive data are employed to determine the contribution of single-step NN scattering to the inclusive scattering yield. This determination is crucial to address whether the inclusive yield arises primarily from these simple hard scattering processes, as is tacitly assumed in most theoretical calculations of this process, or whether non-negligible contributions from more complicated reaction dynamics are present. These data are also employed to study the effect of the nuclear medium on the underlying NN interaction and to show that there is no strong evidence for collectivity in the nuclear response at 200 MeV.
Published: 1999
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7. Precise Measurement of the Deuteron Elastic Structure FunctionA(Q2)

Author: D. Abbott, A. Ahmidouch, H. Anklin, J. Arvieux, J. Ball, S. Beedoe, E. J. Beise, L. Bimbot, W. Boeglin, H. Breuer, R. Carlini, N. S. Chant, S. Danagoulian, K. Dow, J.-E. Ducret, J. Dunne, R. Ent, L. Ewell, L. Eyraud, C. Furget, M. Garçon, R. Gilman, C. Glashausser, P. Gueye, K. Gustafsson, K. Hafidi, A. Honegger, J. Jourdan, S. Kox, G. Kumbartzki, L. Lu, A. Lung, D. Mack, P. Markowitz, J. McIntyre, D. Meekins, F. Merchez, J. Mitchell, R. Mohring, S. Mtingwa, H. Mrktchyan, D. Pitz, L. Qin, R. Ransome, J.-S. Réal, P. G. Roos, P. Rutt, R. Sawafta, S. Stepanyan, R. Tieulent, E. Tomasi-Gustafsson, W. Turchinetz, K. Vansyoc, J. Volmer, E. Voutier, W. Vulcan, C. Williamson, S. A. Wood, C. Yan, J. Zhao, and W. Zhao
Subjects: Physics, Nuclear physics, 010308 nuclear & particles physics, 0103 physical sciences, Structure function, General Physics and Astronomy, Library science, 010306 general physics, 01 natural sciences
Abstract: Centre National de la Recherche Scientifique (France), Commissariat a l'Energie Atomique (France), National Science Foundation, Swiss National Science Foundation, K.C. Wong Foundation
Published: 1999
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8. (α,2α) cluster knockout reaction on9Beand12Cat 580 MeV

Author: M. Khayat, R. E. Warner, Daniel R. Sisan, A. Nadasen, J. Farhat, T. Gu, J. Williams, P. G. Roos, F. Adimi, J. Brusoe, and K. A. G. Rao
Subjects: Physics, Nuclear and High Energy Physics, Nuclear Theory, Cluster (physics), Angular dependence, Atomic physics, Nuclear Experiment, Energy (signal processing)
Abstract: Cross-section measurements of the ${}^{9}\mathrm{Be}{,}^{12}\mathrm{C}(\ensuremath{\alpha},2\ensuremath{\alpha})$ reaction at 580 MeV bombarding energy are presented. The data are compared with distorted-wave impulse approximation calculations. The agreement between theory and experiment suggests a dominance of the quasifree knockout mechanism. The extracted $\ensuremath{\alpha}$-particle spectroscopic factors are in reasonable agreement with theory and proton-induced knockout reactions, unlike measurements for the $(\ensuremath{\alpha},2\ensuremath{\alpha})$ reaction at energies $l~140$ MeV, but still show significant angular dependence.
Published: 1999
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9. Alpha spectroscopic factors for 6Li, 7Li, 9Be and 12C from the (, pα) reaction at 296 MeV

Author: N. Matsuoka, Norihiko Koori, R. E. Warner, Akira Okihana, M. Fujiwara, E. Kubo, T. Yoshimura, Chhanda Samanta, N. S. Chant, S. Kakigi, P. G. Roos, Keisuke Tamura, and K. Ushiro
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Plane wave, Incident energy, Impulse (physics), Atomic physics, Breakup, Spectral line
Abstract: Three-body breakup cross sections and analyzing powers for the 6Li, 7Li, 9Be and 12 C ( p ,pα) reactions were measured at an incident energy of 296 MeV. Data were analyzed using the plane wave impulse approximation (PWIA) and the distorted wave impulse approximation (DWIA) and compared with previous studies. DWIA calculations reproduce shapes of projected spectra and analyzing power distributions fairly well with the exception of the 12 C ( p ,pα) 8 Be reactions. Extracted spectroscopic factors for 6Li, 9Be and 12C are larger than those found in the previous studies. In contrast, extracted spectroscopic factors for 7Li agree with the previous work. This work suggests that the spectroscopic factor for 6Li is ∼ 0.8, independent of incident energies and reaction types.
Published: 1998
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10. Associated Λ production at Jefferson lab

Author: C. C. Chang, Christophe Furget, R. Perrino, H. Blok, J. Cha, J.-O. Hansen, N. S. Chant, T. Angelescu, Pat Welch, I. Niculescu, M. Finn, S. Kox, W. F. Vulcan, G. Savage, E. V. Hungerford, G. J. Lolos, O. K. Baker, B. Zeidman, D. G. Meekins, Ts A. Amatuni, L. Kramer, J. Volmer, L. G. Tang, Pete Markowitz, W. Kim, F. Garibaldi, T. Saito, H. Breuer, E. J. Beise, R. Sawafta, Laurent Eyraud, S. Majewski, R. Madey, Liliana Teodorescu, J. S. Real, J. Martoff, K. Gustafsson, John C. Mitchell, D. Koltenuk, T. Eden, Paul Gueye, G. Niculescu, M. Harvey, R. De Leo, J. Reinhold, D. F. Geesaman, Dipanwita Dutta, K. Bailey, E. Cisbani, V. Tadevosian, A. Ahmidouch, D. Gaskell, C. S. Armstrong, J. A. Dunne, M. Maeda, T. Leone, C. Jackson, S. Stepanyan, H. Mkrtchyan, V. Frolov, P. G. Roos, S. Beedoe, W. J. Cummings, A. F. Lung, R. D. Carlini, P. Stoler, A. Mihul, C. Yan, D. H. Potterveld, K. Kino, W. Hinton, Mauro Iodice, L. Ewell, Ketevi Assamagan, R. Williams, S. Danagoulian, Gabriel Niculescu, Rolf Ent, Brian Raue, J. W. Price, T. Fortune, T. Terasawa, Hiroaki Tsubota, D. Abbott, G. Collins, S. Mtingwa, S. Frullani, F. Duncan, P. Ambrozewicz, R. E. Segel, K. Beard, R. Mohring, S. A. Wood, D. J. Mack, Stephen Avery, C. E. Keppel, and G.M. Urcivoli
Subjects: Nuclear reaction, Physics, Nuclear physics, Nuclear and High Energy Physics, Meson, Hadron, Virtual particle, Elementary particle, Atomic physics, Strangeness, Lambda baryon, Sigma baryon
Abstract: The 1 H(e, e′K + )Λ and 1 H(e,e′K + )Σ 0 reactions were studied as a function of the squared four-momentum-transfer, Q 2 , and the virtual photon polarization, e, thus enabling the separation of the longitudinal and transverse parts of the cross section. The existence of a sizable longitudinal component for the 1 H(e,e′K + )Λ reaction seems to be indicated by these data.
Published: 1998
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11. Spin-dependent scattering of deeply bound nucleons

Author: C. A. Miller, P. W. Green, Y. Ye, D. A. Hutcheon, R. Schubank, M. Ahmad, D. J. Mack, D. Frekers, K. Hicks, W.J. McDonald, P. G. Roos, W.C. Olsen, L.G. Greeniaus, R. Abegg, N. S. Chant, and P. Kitching
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Recoil, Scattering, Nuclear Theory, Observable, Kinematics, Impulse (physics), Nuclear Experiment, Nucleon
Abstract: Exclusive measurements of the analyzing power and two spin-transfer observables for nucleon knockout from an 16 O target are presented, at kinematic conditions chosen to emphasize interactions in the nuclear interior. The analyzing power data are substantially reduced in comparison with values calculated in the distorted wave impulse approximation ~DWIA! using the free nucleon-nucleon interaction, particularly for knockout of the deeply bound 1s 1/2 nucleons. Inclusion of density dependence for the interaction in the calculations improves the agreement with the data, but does not provide a satisfactory description for nucleon knockout from 16 O. Spin-orbit distortions are shown to strongly affect the DWIA predictions of the 1 s 1/2 analyzing powers over most of the experimental kinematic range, but notably not near the points of negligible recoil momentum. Hence these data offer constraints on the optical potentials and independently on the two-body effective interaction. @S0556-2813~98!02104-9# PACS number~s!: 25.40.Ep, 24.70.1s, 24.10.Eq, 13.75.2n
Published: 1998
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12. Analyzing powers for→1(π+,π+p) atTπ=165 and 240 MeV

Author: T. A. Greco, R. Meier, Patrick Hautle, H. Breuer, T. Dooling, J. J. Lawrie, S. Mango, S. Ritt, T. Gu, A. P. Dvoredsky, K. Koch, Thomas H. Chang, M. Wang, F. Adimi, B.v. Brandt, Pete Markowitz, P. G. Roos, Avraham Klein, J. Huffman, J. A. Konter, M. Khayat, H. L. Chen, J. P. Haas, A.I. Kovalev, B. A. Raue, Z. N. Lin, James J. Kelly, N. S. Chant, T. Payerle, G. S. Kyle, and B. S. Flanders
Subjects: Elastic scattering, Nuclear reaction, Nuclear physics, Physics, Nuclear and High Energy Physics, Pion, Pion beam, Scattering, Computer Science::Information Retrieval, Atomic physics
Abstract: We have measured the analyzing power for elastic scattering of {pi}{sup +} from a target of polarized {sup 1}H. Data were taken for incident pion beam energies of 165 and 240 MeV at several pion scattering angles. The current data generally agree with previously existing measurements of {ital A}{sub {ital y}} for this reaction and also with results of the SAID phase-shift analysis program. In most cases the new data are of higher precision than previously existing data. {copyright} {ital 1996 The American Physical Society.}
Published: 1996
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13. Analyzing powers for theH2(p→,pn)1H reaction at 200 MeV

Author: P.J. Pella, Richard Madey, W. Pairsuwan, N. S. Chant, J. W. Watson, M. Ahmad, P. G. Roos, and B. S. Flanders
Subjects: Scattering cross-section, Physics, Nuclear and High Energy Physics, Recoil, Degree (graph theory), Deuterium, Proton, Computer Science::Information Retrieval, Neutron, Atomic physics, Nuclear Experiment, Wave function, Omega
Abstract: We measured the analyzing power {ital A}{sub {ital y}} and the triple differential cross section {ital d}{sup 3}{sigma}/{ital d}{Omega}{sub {ital pd}}{Omega}{sub {ital ndE}}{sub {ital p}} for the {sup 2}H({ital {rvec p}},{ital pn}){sup 1}H reaction at 200 MeV. Coplanar coincidence data were taken for all combinations of neutron angles {theta}{sub {ital n}}=35{degree}, 45{degree}, or 55{degree} with proton angles {theta}{sub {ital p}}=35{degree}, 45{degree}, or 52{degree}. Protons were detected with a {Delta}{ital E}-{ital E} telescope with a 1000-{mu}m silicon surface barrier {Delta}{ital E} detector and a plastic scintillator {ital E} detector. Neutrons were detected with large-volume plastic scintillators at flight paths of 17.5 or 18 m. The overall neutron separation-energy resolution was about 3 MeV. Data are compared with plane-wave impulse-approximation calculations with a Hulthen deuteron wave function and {ital p}-{ital n} cross sections and analyzing powers obtained from {ital N}-{ital N} phase shifts. The agreement between these calculations and the data is generally good for the cross sections. The agreement for the analyzing powers is good near the point of zero recoil momentum. Our results suggest that the deuteron is a good ``neutron target`` for recoil momenta {lt}100 MeV/{ital c}.
Published: 1995
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14. Photopion production from polarized nuclear targets

Author: N. S. Chant and P. G. Roos
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Amplitude, Pion, Nuclear Theory, Nuclear structure, Observable, Impulse (physics), Nuclear Experiment, Nucleon, Polarization (waves)
Abstract: Recently nonlocal distorted wave impulse approximation (DWIA) calculations for A(\ensuremath{\gamma},\ensuremath{\pi}N)B photopion production reactions have been reported. In this paper we examine the factorized DWIA formulation to help clarify some of the underlying physics content inherent in such measurements. We also extend the formulation to the case of polarized targets and to the measurement of the emitted nucleon polarization. We show that with reasonable approximations one can formally write the three-body reaction spin observables in terms of products of the two-body \ensuremath{\gamma}+N\ensuremath{\rightarrow}\ensuremath{\pi}+N spin observables, the polarization of the struck nucleon which depends on nuclear structure, and an effective polarization created by the distortions. Calculations are presented for two nuclear targets for which adequate polarization has been obtained to utilize them in experiments; viz., $^{13}\mathrm{C}$ and $^{19}\mathrm{F}$. These calculations provide typical predictions which might be compared to experimental data to search for evidence of medium modifications of the pion production amplitudes.
Published: 1995
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15. Distorted-wave impulse approximation calculations of proton polarization followingπ+absorption in nuclei

Author: N. S. Chant, P. G. Roos, and M. Khayat
Subjects: Nuclear reaction, Baryon, Physics, Nuclear and High Energy Physics, Proton, Quantum electrodynamics, Hadron, Elementary particle, Fermion, Impulse (physics), Atomic physics, Nucleon
Abstract: We present distorted-wave impulse approximation calculations for the polarization of outgoing protons resulting from ([pi][sup +],2[ital p]) reactions using a quasideuteron absorption model with phenomenological amplitudes for the [pi][ital NN] vertex. As an example of the interesting interference and distorted-wave effects that can be observed from such reactions, we study the case of a [sup 12]C target. Calculations are also compared to the recently published data for the nuclei [sup 3,4]He.
Published: 1995
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16. Measurement of the Parity-Violating Asymmetry in Inclusive Electroproduction ofπ−near theΔ0Resonance

Author: V. Tadevosyan, M. Stutzman, M. K. Jones, R. Suleiman, J. Hansknecht, G. Guillard, Fatiha Benmokhtar, Darko Androić, S. Kox, W. D. Ramsay, Michael Pitt, W. T. H. van Oers, J. Roche, T. Horn, A. Micherdzinska, S. L. Bailey, E. Voutier, D. T. Spayde, H. Breuer, P. Bosted, Douglas H Beck, G. Flores, Christophe Furget, Michael Gericke, S. Wells, R. D. McKeown, Neven Simicevic, M. Muether, M. Poelker, E. J. Beise, Y. C. Chao, D. Gaskell, A. Coppens, M. Versteegen, J. Grames, B. P. Quinn, D. S. Armstrong, G. R. Smith, M. Mihovilovic, Junyu Liu, C. L. Capuano, L. Bimbot, S. E. Williamson, J. Birchall, S. K. Phillips, Wolfgang Korsch, Juliette Mammei, S. A. Wood, P. M. King, J. Arvieux, S. F. Pate, H. Mkrtchyan, C. Ellis, S. A. Page, P. G. Roos, P. Pillot, G. B. Franklin, W. F. Vulcan, T. Seva, J. Schaub, L. Lee, V. Papavassiliou, J. W. Martin, Jay Benesch, J. S. Real, C. A. Davis, and A. Lung
Subjects: Physics, Particle physics, Chiral perturbation theory, 010308 nuclear & particles physics, Scattering, media_common.quotation_subject, Hyperon, General Physics and Astronomy, Inelastic scattering, 01 natural sciences, Asymmetry, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Electron scattering, media_common
Abstract: The parity-violating (PV) asymmetry of inclusive π- production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasifree photoproduction off the neutron via the Δ^0 resonance. In the context of heavy-baryon chiral perturbation theory, this asymmetry is related to a low-energy constant d_Δ^- that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated d_Δ^- in a model benchmarked by the large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from A_γ^-=-5.2 to +5.2 ppm. The measurement performed in this work leads to A_γ^-=-0.36±1.06±0.37±0.03 ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V_(ud)/V_(us). The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form factors using PV electron scattering.
Published: 2012
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17. Excitation function forHe4(π+,pp)2H two-nucleon absorption across the Δ resonance

Author: M. A. Khandaker, T. Tacik, J. Konijn, G. S. Kyle, Dan Zhang, S. Mukhopadhyay, B. S. Flanders, M. Khayat, C.T.A.M. de Laat, F. Adimi, P. G. Roos, H. Breuer, Th. S. Bauer, and M.H. Wang
Subjects: Physics, Baryon, Nuclear reaction, Excitation function, Nuclear and High Energy Physics, Pion, Absorption cross section, Resonance, Atomic physics, Nucleon, Delta baryon
Abstract: Angular distributions and total cross sections for the [sup 4]He([pi][sup +],[ital pp])[sup 2]H reaction have been measured with small relative uncertainties at incident energies of [ital T][sub [pi]][sup +]=64, 87, 114, 162, 217, 278, and 327 MeV. The results strongly support the quasideuteron absorption model for pion absorption on two nucleons, which is found to contribute only [approx]50% to the total absorption cross section near the [Delta] resonance. All essential reaction channels of pion absorption near the [Delta] resonance on heavier nuclei seem to be present in [sup 4]He, but not in [sup 3]He. Any nuclear-density-related increase of pion absorption in [sup 4]He relative to [sup 2]H is [lt]50% and no binding energy effect is found.
Published: 1994
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18. Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasielastic Electron-Deuteron Scattering

Author: Marc Vanderhaeghen, J. Roche, M. K. Jones, Jay Benesch, J. Hansknecht, A. Lung, J. W. Martin, H. Breuer, W. F. Vulcan, Christophe Furget, S. F. Pate, H. Mkrtchyan, G. Flores, Michael Gericke, R. Suleiman, Darko Androić, S. Kox, G. Guillard, T. Seva, M. Stutzman, S. A. Page, J. Schaub, L. Lee, Douglas H Beck, Fatiha Benmokhtar, M. Muether, V. Papavassiliou, S. Wells, C. L. Capuano, T. Horn, R. D. McKeown, W. D. Ramsay, W. T. H. van Oers, P. Bosted, S. A. Wood, E. Voutier, D. T. Spayde, J. S. Real, M. Poelker, G. B. Franklin, C. A. Davis, D. Gaskell, B. Pasquini, P. M. King, B. P. Quinn, L. Bimbot, S. E. Williamson, Neven Simicevic, Y. C. Chao, Wolfgang Korsch, J. Birchall, Juliette Mammei, P. G. Roos, J. Grames, C. Ellis, M. Versteegen, S. K. Phillips, J. Arvieux, A. Micherdzinska, D. S. Armstrong, G. R. Smith, M. Mihovilovič, E. J. Beise, V. Tadevosyan, A. Coppens, Michael Pitt, S. L. Bailey, Junyu Liu, P. Pillot, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and G0
Subjects: Nuclear Theory, General Physics and Astronomy, axial-vector current, FOS: Physical sciences, Inelastic scattering, Mott scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], strange quark, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology (hep-ph), parity-violating asymmetries, charge and magnetic nucleon form factors, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Elastic scattering, Physics, Quasielastic scattering, 010308 nuclear & particles physics, Scattering, Small-angle neutron scattering, NATURAL SCIENCES. Physics, PRIRODNE ZNANOSTI. Fizika, High Energy Physics - Phenomenology, Quasielastic neutron scattering, Physics::Accelerator Physics, High Energy Physics::Experiment, Scattering theory, Atomic physics
Abstract: We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasi-elastic scattering on the deuteron, at backward angles (lab scattering angle of 108 degrees) for Q2 = 0.22 GeV^2/c^2 and 0.63 GeV^2/c^2 at beam energies of 362 MeV and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is also in agreement with theory.
Published: 2011
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19. The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles

Author: T. Horn, G. A. Rutledge, R. M. Laszewski, A. Kolarkar, R. Hasty, F. Merchez, E. Liatard, K. Grimm, W. F. Vulcan, J. Yun, H. C. Fenker, R. Carr, R. Suleiman, D. McKee, J. Roche, R. Neveling, K. Johnston, M. Versteegen, Raphael Noel Tieulent, A. Coppens, R. Frascaria, S. A. Wood, T. Averett, P. Pillot, S. Kox, D. Marchand, D. S. Armstrong, K. A. Griffioen, G. R. Smith, C. Yan, G. Guillard, J. Lachniet, E. Voutier, K. W. McFarlane, G. Quéméner, J. Schaub, L. Lee, D. S. Dale, Michael Gericke, A. Hawthorne Allen, Fatiha Benmokhtar, V. Zeps, E. J. Beise, M. Muether, R. Clark, D. J. Mack, Michael Pitt, Jay Benesch, Jonathan W. Martin, W. T. H. van Oers, T. A. Porcelli, J. A. Secrest, W. D. Ramsay, A. A. Cowley, S. Niccolai, H. Guler, C. L. Capuano, S. L. Bailey, J. Arvieux, N. S. Chant, L. Bimbot, P. Kammel, C. Ellis, Bryan J. Moffit, R. Asaturyan, G. Batigne, D. T. Spayde, W. R. Falk, P. M. King, Douglas H Beck, A. Micherdzinska, Takeyasu Ito, John Musson, R. D. McKeown, S. A. Page, S. Wells, J. Kuhn, Y. C. Chao, K. Nakahara, B. Guillon, S. E. Williamson, J. Grames, L. Hannelius, M. Morlet, H. Breuer, J. Van de Wiele, S. K. Phillips, J. Hansknecht, J. S. Real, A. S. Biselli, R. J. Woo, S. Covrig, M. K. Jones, J. Lenoble, S. Ong, H. Mkrtchyan, M. Poelker, D. Gaskell, S.G. Stepanyan, T. A. Forest, C. A. Davis, A. Lung, J. M. Finn, M. Stutzman, S. F. Pate, T. Seva, E. Korkmaz, A. W. Rauf, V. Papavassiliou, P. Brindza, G. A. MacLachlan, V. Tadevosyan, J. Birchall, R. Kazimi, C. Furget, Juliette Mammei, Glen A. Warren, Neven Simicevic, P. G. Roos, D. Nilsson, G. B. Franklin, K. Gustafsson, Wolfgang Korsch, Darko Androić, M. Mihovilovic, Jin Liu, P. Bosted, R. D. Carlini, T. Ries, B. P. Quinn, Mines Nantes (Mines Nantes), Laboratoire SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and G0
Subjects: Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, FOS: Physical sciences, Electron, Mott scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, magnetic spectrometer, liquid hydrogen target, polarized electron beam, parity-violation, electron scattering, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Instrumentation, Cherenkov radiation, Elastic scattering, Physics, Spectrometer, 010308 nuclear & particles physics, Scattering, Instrumentation and Detectors (physics.ins-det), Small-angle neutron scattering, Electron scattering
Abstract: In the G0 experiment, performed at Jefferson Lab, the parity-violating elastic scattering of electrons from protons and quasi-elastic scattering from deuterons is measured in order to determine the neutral weak currents of the nucleon. Asymmetries as small as 1 part per million in the scattering of a polarized electron beam are determined using a dedicated apparatus. It consists of specialized beam-monitoring and control systems, a cryogenic hydrogen (or deuterium) target, and a superconducting, toroidal magnetic spectrometer equipped with plastic scintillation and aerogel Cerenkov detectors, as well as fast readout electronics for the measurement of individual events. The overall design and performance of this experimental system is discussed., Comment: Submitted to Nuclear Instruments and Methods
Published: 2011
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20. Energy dependence of two-nucleon pion absorption onO16

Author: P. A. Amaudruz, G. S. Kyle, S. D. Hyman, Dieter Renker, U. Sennhauser, D. J. Mack, J. D. Silk, Th. S. Bauer, B. G. Ritchie, C. H. Q. Ingram, N. S. Chant, F. Khazaie, W. J. Burger, H. Breuer, R. A. Schumacher, and P. G. Roos
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Nuclear Theory, Hadron, Absorption cross section, Elementary particle, Charged particle, Nuclear physics, Baryon, Pion, Atomic physics, Nuclear Experiment, Nucleon
Abstract: Inclusive [sup 16]O([pi][sup +],[ital p]) and exclusive [sup 16]O([pi][sup +],2[ital p]) data are presented for 115 MeV and 165 MeV pions. Using a combination of distorted-wave impulse approximation (DWIA) calculations for two-nucleon absorption and phase space simulations for more complicated processes, the data are fit and the total direct two-nucleon absorption cross sections are extracted. These cross sections fall faster with energy than [pi][sup +][ital d][r arrow][ital pp]. The DWIA calculations were used to calculate the effects of final state interactions (FSI). After correcting for FSI, the two-nucleon absorption process is found to dominate at 115 MeV, becoming less important as the incident energy increases to 165 MeV. The decrease with energy in the two-nucleon fraction of the total absorption cross section is found to be in remarkably good agreement with theoretical predictions.
Published: 1993
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21. N*electroproduction and propagation in nuclei

Author: J. Morrison, A. Perry, V. A. Punjabi, P. Boberg, L. Ghedira, H. Baghaei, D. Chang, E. J. Winhold, J. E. Wise, D. J. Margaziotis, M. B. Epstein, P. E. Ulmer, P. G. Roos, John M. Finn, K. A. Aniol, C. P. Sargent, J. R. Calarco, C. C. Chang, W. U. Boeglin, W. W. Sapp, R. W. Lourie, B. H. Cottman, S. Penn, N. S. Chant, C. E. Hyde-Wright, Nasser Kalantar-Nayestanaki, R. R. Whitney, William Bertozzi, J. Glickman, Larry Weinstein, C. F. Perdrisat, and J. Nelson
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Light nucleus, Meson, Initial momentum, Bremsstrahlung, Atomic physics
Abstract: We have measured the [sup 12]C([gamma][sup *],[pi][sup [minus]][ital p])[sup 11]C[sub g.s.] cross section using virtual bremsstrahlung at three points at invariant masses of 1444 and 1530 MeV. At low neutron initial momentum ([ital p][sub [ital m]][approx]60 MeV/[ital c]) and large [ital N][sup *] momentum ([ital p][sub [ital N]][sup *][approx]750 MeV/[ital c]) the measured cross section is at or below the distorted wave impulse approximation (DWIA) calculation. At larger initial momentum ([ital p][sub [ital m]][approx]220 MeV/[ital c]) and smaller [ital N][sup *] momentum ([ital p][sub [ital N]][sup *][approx]500 MeV/[ital c]), the measured cross section is almost twice as large as the DWIA calculation. This discrepancy might be due to [ital N][sup *]-nucleus interactions.
Published: 1993
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22. Cross sections and Rosenbluth separations inH1(e,e′K+)Λup toQ2=2.35 GeV2

Author: D. J. Margaziotis, John C. Mitchell, W. Hinton, A. Camsonne, C. C. Chang, S. A. Wood, L. G. Tang, S. Marrone, Kevin Fissum, Paul Gueye, H. Ueno, B. Hu, Salvatore Frullani, Douglas Higinbotham, M. K. Jones, K. Wijesooriya, K. Wang, L. Cole, J. Reinhold, M. Coman, K. Kozlov, K. Kanda, S. K. Nanda, M. Palomba, R. Roche, P. G. Roos, P. E. Ulmer, J. Gomez, W. U. Boeglin, Friedrich Klein, Nilanga Liyanage, L. Lagamba, Y. Sato, A. Uzzle, L. Zhu, Brian Raue, Mauro Iodice, J. J. LeRose, S. Širca, T. Miyoshi, Antonin Vacheret, C. E. Keppel, Bogdan Wojtsekhowski, Pete Markowitz, Franco Garibaldi, P. King, G. M. Huber, T. Horn, R. Michaels, Sonja Dieterich, F. Dohrmann, O. Filoti, R. De Leo, Dipanwita Dutta, C. F. Perdrisat, M. Sotona, J. Cha, J. P. Chen, F. Gilman, G. M. Urciuoli, A. Saha, Olivier Gayou, E. Chudakov, Laird Kramer, J. O. Hansen, E. Cisbani, P. Bydžovský, K. McCormick, X. Zheng, Rolf Ent, C. Jackson, V. Pattichio, K. Baker, A. J. Sarty, F. Cusanno, A. Deur, C. W. de Jager, K. A. Aniol, K. Kramer, H. Breuer, V. A. Punjabi, N. S. Chant, B. Reitz, E. Piasetzky, X. Jiang, and I. Yaron
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Meson, Hadron, Momentum transfer, Lambda baryon, Lambda, Nuclear physics, Photon polarization, High Energy Physics::Experiment, Nuclear cross section, Nuclear Experiment
Abstract: The kaon electroproduction reaction 1H(e,e'K+)Lambda was studied as a function of the virtual-photon four-momentum, Q2, total energy, W, and momentum transfer, t, for different values of the virtual- photon polarization parameter. Data were taken at electron beam energies ranging from 3.40 to 5.75 GeV. The center of mass cross section was determined for 21 kinematics corresponding to Q2 of 1.90 and 2.35 GeV2 and the longitudinal, sigmaL, and transverse, sigmaT , cross sections were separated using the Rosenbluth technique at fixed W and t. The separated cross sections reveal a flat energy dependence at forward kaon angles not satisfactorily described by existing electroproduction models. Influence of the kaon pole on the cross sections was investigated by adopting an off-shell form factor in the Regge model which better describes the observed energy dependence of sigmaT and sigmaL.
Published: 2010
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23. Recent results from the G0 experiment

Author: Douglas H Beck, R. D. McKeown, C. L. Capuano, M. Mihovilovic, M. Versteegen, S. Kox, Joseph Grames, W. D. Ramsay, C. Furget, G. Guillard, A. Coppens, J. Schaub, L. Lee, D. T. Spayde, G. Flores, S. A. Page, Junyu Liu, Michael Gericke, P. M. King, C. Ellis, F. Benmokhtar, E. Voutier, P. G. Roos, E. J. Beise, W. T. H. van Oers, L. Bimbot, V. Tadevosyan, J. S. Real, H. Breuer, S. F. Pate, H. Mkrtchyan, Jay Benesch, S. E. Williamson, S. K. Phillips, J. Roche, S. A. Wood, J. Hansknecht, T. Seva, M. Muether, V. Papavassiliou, S. Wells, W. F. Vulcan, T. Horn, Y. C. Chao, C. A. Davis, J. W. Martin, B. P. Quinn, M. Poelker, Neven Simicevic, D. Gaskell, M. K. Jones, Wolfgang Korsch, A. Micherdzinska, Darko Androić, A. Lung, P. Bosted, R. Suleiman, J. Arvieux, P. Pillot, M. Stutzman, J. Birchall, Juliette Mammei, G. B. Franklin, Michael Pitt, S. L. Bailey, D. S. Armstrong, G. R. Smith, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and G0
Subjects: Physics, Quark, Particle physics, Strange quark, Scattering, QC1-999, Momentum transfer, Nuclear Theory, Electron, Weak interaction, 7. Clean energy, Nuclear physics, Dipole, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Nucleon, Nuclear Experiment
Abstract: We have measured parity violating asymmetries in elastic electron-proton and quasi-elastic electrondeuteron scattering at backward electron angle. These measurements have been done at two momentum transfers : Q2 = 0.22 and 0.63 (GeV/c)2 . Together with our previous forward angle measurement [1], we can extract strange quark contributions to the electromagnetic form factors of the nucleon, as well as nucleon axial form factor coming from the neutral weak interaction. The results indicate a strange quark magnetic contribution close to zero at these Q2 , and a possible non zero strange quark electric contribution for the high Q2 . The ﬁrst Q2 behavior measurement of the nucleon axial form factor in elastic electron scattering shows a good agreement with radiative corrections calculated at Q2 = 0 and with a dipole form using the axial mass determined in neutrino scattering.
Published: 2010
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24. Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment

Author: A. Coppens, A. Lung, Junyu Liu, J. Arvieux, M. Stutzman, J. Schaub, Fatiha Benmokhtar, W. D. Ramsay, J. Roche, D. T. Spayde, S. Wells, C. L. Capuano, S. F. Pate, Y. C. Chao, L. Bimbot, P. Pillot, T. Horn, B. P. Quinn, J. Grames, J. Hansknecht, T. Seva, M. I. W. Gericke, Wolfgang Korsch, W. F. Vulcan, H. Breuer, M. Poelker, J. S. Real, V. Papavassiliou, J. Benesch, R. Suleiman, Douglas H Beck, J. W. Martin, M. Muether, Juliette Mammei, G. B. Franklin, Darko Androić, Michael Pitt, R. D. McKeown, S. K. Phillips, H. Mkrtchyan, S. A. Page, C. A. Davis, P. Bosted, G. Flores, M. Versteegen, Neven Simicevic, C. Furget, S. Kox, P. G. Roos, E. Voutier, S. L. Bailey, L. Lee, W. T. H. van Oers, P. M. King, J. Birchall, D. S. Armstrong, G. R. Smith, M. Mihovilovič, D. Gaskell, M. K. Jones, E. J. Beise, G. Guillard, S. A. Wood, V. Tadevosyan, A. Micherdzinska, C. Ellis, S. E. Williamson, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and G0
Subjects: Quark, Strange quark, Particle physics, media_common.quotation_subject, Nuclear Theory, FOS: Physical sciences, axial-vector current, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Strangeness, strange quark, 01 natural sciences, 7. Clean energy, Asymmetry, Nuclear physics, parity-violating asymmetries, charge and magnetic nucleon form factors, 0103 physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, media_common, Elastic scattering, Physics, Neutral current, 010308 nuclear & particles physics, Scattering, NATURAL SCIENCES. Physics, PRIRODNE ZNANOSTI. Fizika, High Energy Physics::Experiment, Nucleon, 11.30.Re, 13.60.-r, 14.20.Dh, 25.30.Bf
Abstract: We have measured parity-violating asymmetries in elastic electron-proton and quasi-elastic electron-deuteron scattering at Q^2 = 0.22 and 0.63 GeV^2. They are sensitive to strange quark contributions to currents in the nucleon, and to the nucleon axial current. The results indicate strange quark contributions of < 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial current at these four-momentum transfers., 5 pages, 2 figures, changed references, typo, and content
Published: 2010
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25. Dominance of the two-nucleon mechanism inO16(π+,pp) at 115 MeV

Author: N. S. Chant, H. Breuer, Th. S. Bauer, B. G. Ritchie, F. Khazaie, P. A. Amaudruz, Dieter Renker, R. A. Schumacher, C. H. Q. Ingram, S. D. Hyman, P. G. Roos, J. D. Silk, D. J. Mack, W. J. Burger, G. S. Kyle, and U. Sennhauser
Subjects: Baryon, Physics, Nuclear reaction, Nuclear and High Energy Physics, Hadron, Absorption cross section, Elementary particle, Atomic physics, Nucleon, Charged particle, Spectral line
Abstract: Singles {sup 16}O({pi}{sup +},{ital p}) and coincidence {sup 16}O({pi}{sup +},2{ital p}){sup 14}N measurements have been made at {ital T}{sub {pi}}=115 MeV over an extended range of the phase space of the two final-state protons. The coincidence measurements have a missing-mass resolution of 4 MeV. The direct two-nucleon absorption cross section extracted from the data is 58{plus minus}8 mb. After corrections for final-state interactions, it was found that the two-nucleon {pi}{sup +}+{ital np}{r arrow}{ital pp} process accounts for about 76% of the total absorption cross section, and thus is the dominant absorption mechanism. Evidence for absorption on {ital s}-{ital p} pairs is seen as a broad bump near 32 MeV of excitation. At backward angles the inclusive {sup 16}O({pi}{sup +},{ital p}) spectra show a distinct absorption peak, an important feature not previously observed. Comparisons of distorted wave impulse approximation calculations to both the coincidence data and inclusive data are presented.
Published: 1992
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26. Quasifree knockout inO16(p,2p)15N at an incident energy of 151 MeV

Author: F. D. Smit, S. V. Förtsch, J. J. Lawrie, P. G. Roos, D. M. Whittal, J. V. Pilcher, G. C. Hillhouse, and A. A. Cowley
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Distribution (mathematics), Factorization, Excited state, Phase space, Nuclear structure, Atomic physics, Space (mathematics), Ground state
Abstract: Cross sections for the reaction {sup 16}O({ital p},2{ital p}){sup 15}N to the ground state and excited state at 6.32 MeV have been measured at an incident energy of 151 MeV. The data are in good agreement with distorted-wave impulse-approximation calculations. The factorization approximation is found to be valid for the region of phase space studied. The extracted spectroscopic factors are reasonably consistent with those determined in other experiments, and they are also compatible with results of a weak-coupling nuclear structure model.
Published: 1991
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27. Charged pion form factor betweenQ2=0.60and2.45 GeV2. II. Determination of, and results for, the pion form factor

Author: C. E. Keppel, D. J. Margaziotis, L. M. Qin, S. Vidakovic, John C. Mitchell, B. Zihlmann, T. Eden, V. Tadevosyan, Y. Okayasu, J. Arrington, D. H. Potterveld, J. Roche, Toshinobu Miyoshi, D. van Westrum, B. Mueller, K. A. Aniol, G. Niculescu, E. J. Brash, S. A. Wood, Ketevi Assamagan, K. Vansyoc, P. H. Kim, W. Zhao, D. McKee, H. C. Fenker, W.U. Boeglin, C. S. Armstrong, D. J. Mack, A. Matsumura, Stephen Avery, E. J. Beise, H. E. Jackson, D. Pitz, C. Xu, G. J. Lolos, A. J. Sarty, C. Yan, Andreas Klein, Jin Liu, M. E. Christy, P. E. Reimer, X. Zheng, I. K. Shin, J. Reinhold, E. F. Gibson, W. F. Vulcan, W. Hinton, S. Stepanyan, P. G. Roos, Ronald Gilman, C. C. Chang, R. van der Meer, D. Abbott, D. Gaskell, M. K. Jones, I. Niculescu, C. F. Perdrisat, Brynle Barrett, V. Kovaltchouk, H. Mkrtchyan, V. Tvaskis, A. F. Lung, Lubomir Pentchev, H. Anklin, Oliver Keith Baker, Geoffrey Smith, Pete Markowitz, Rolf Ent, Glen A. Warren, K. Gustafsson, M. Liang, C. Bochna, J. Volmer, G. M. Huber, P. M. King, D. Koltenuk, H. P. Blok, J. A. Dunne, L. G. Tang, V. A. Punjabi, D. G. Meekins, S. Jin, W. Kim, N. S. Chant, H. Breuer, Tanja Horn, and R. J. Holt
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Bethe–Salpeter equation, 010308 nuclear & particles physics, Hadron, Lattice field theory, Magnetic monopole, Form factor (quantum field theory), Sigma, Particle accelerator, 7. Clean energy, 01 natural sciences, Charged particle, law.invention, Nuclear physics, Pion, law, Charge radius, 0103 physical sciences, Neutron, Invariant mass, Nucleon, 010306 general physics
Abstract: Cross sections for the reaction {sup 1}H(e,e'{Pi}{sup +})n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q{sup 2} = 0.60 to 2.45 GeV{sup 2} at an invariant mass of the virtual photon-nucleon system of W = 1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions {sigma}{sub L},{sigma}{sub T}, {sigma}{sub LT}, and {sigma}{sub TT}. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q{sup 2} are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction {sup 1}H(e,e'{Pi}{sup +})n.
Published: 2008
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28. Three trion breakup of 6Li + 3He at 132 MeV

Author: E. Karaoglan, A. Nadason, T. A. Carey, I. Slausa'c, J. M. Lambert, P. G. Roos, N. S. Chant, Michael I. Haftel, P. A. Treado, and L. T. Myersa
Subjects: Elastic scattering, Nuclear physics, Physics, Scattering, Phase space, Plane wave, Impulse (physics), Trion, Breakup, Spectral line
Abstract: A simple model which treats the h-h and h-t quasifree scattering (QFS) in the 3He + 6Li interaction as a 3-body problem proved to be better than the plane wave impulse approximation (PWIA) ~. The S-wave interaction 3-body model (3BM) predicted the shape and the absolute cross section for the h-h and h-t QFS with E. = 45 MeV~ ) i while the PWIA did not reproduce the shape of the spectra, predicted the cross section larger by a factor of 15-30 and did not predict the ratio of the h-h vs. h-t QFS. We realize that the simple 3BM is inadequate (trion-trion interactions cannot be represented by S-wave forces, inelastic channels are always open for the trion-trion system and 6Li is not predominantly a h + t structure) but we suggest that it is worthwhile to investigate: a) the trion-trion QFS at higher energies to determine whether the PWIA will provide a reasonable fit to the data and whether the S-wave 3BM will be less applicable and b) the 3He + 6Li breakup in the region of phase space where short range and effective 3-body forces play a significant role. Since the trions are bound by 15.8 MeV in 6Li, features due to the effective 3-body force should be more pronounced than in weakly bound systems.
Published: 2008
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29. ReactionNi58(π+,pp) atTπ+=160 MeV

Author: P. G. Roos, K. Gotow, R. P. Redwine, D. M. Lee, B. G. Ritchie, W. J. Burger, G. S. Blanpied, N. S. Chant, J. D. Silk, H. Ziock, M. Blecher, E. J. Beise, H. Breuer, Shalev Gilad, G. Ciangaru, and B. M. Preedom
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Pion, Degree (graph theory), Scattering, Nuclear Theory, Absorption cross section, Absorption (logic), Atomic physics, Nuclear Experiment, Nucleon, Energy (signal processing)
Abstract: The reaction {sup 58}Ni({pi}{sup +},{ital pp}) was studied with good energy resolution for an incident pion energy of 160 MeV. The angular correlation of the outgoing protons was measured for {theta}{sub lab}=30{degree}, 75{degree}, and 130{degree}. From these angular correlations the contribution from direct two-nucleon absorption was extracted. A Monte Carlo calculation modeling the absorption process in terms of initial-state scattering of the pion before absorption, two-nucleon absorption, and final-state scattering of the outgoing nucleons is compared to the data. We conclude that within this framework the two-nucleon mechanism can account for less than half of the total absorption cross section in {sup 58}Ni. We report results for the low-energy coincidence proton spectra (down to 5 MeV) which suggest that most of these protons come from evaporation. Angular correlation data for the reaction {sup 58}Ni({pi}{sup {minus}},{ital pp}) are also presented.
Published: 1990
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30. O16(π+,2p) reaction at 165 MeV

Author: J. D. Silk, B. G. Ritchie, P. A. Amaudruz, D. J. Mack, S. D. Hyman, F. Khazaie, C. H. Q. Ingram, N. S. Chant, U. Sennhauser, G. S. Kyle, H. Breuer, R. A. Schumacher, P. G. Roos, Th. S. Bauer, W. J. Burger, and Dieter Renker
Subjects: Physics, Nuclear reaction, Baryon, Nuclear physics, Nuclear and High Energy Physics, Angular correlation, Hadron, Pi, Physical chemistry, Nucleon, Charged particle, Ion
Published: 1990
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31. Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

Author: L. Lee, G. Batigne, S. Covrig, D. McKee, K. A. Griffioen, R. Kazimi, W. D. Ramsay, L. Bimbot, J. Lachniet, C. Furget, Bryan J. Moffit, Glen A. Warren, K. Johnston, E. Voutier, A. Hawthorne Allen, G. Quéméner, R. Carr, S. E. Williamson, P. Kammel, T. Averett, J. Van de Wiele, S. Stepanyan, B. Guillon, W. Falk, E. Liatard, D. Marchand, P. G. Roos, B. Loupias, M. Morlet, E. J. Beise, K. W. McFarlane, J. S. Real, A. A. Cowley, T. Horn, J. Lenoble, S. Wells, J. Kuhn, Neven Simicevic, V. Sulkosky, T. A. Forest, H. Guler, W. T. H. van Oers, E. Boukobza, Y. C. Chao, K. Nakahara, H. Breuer, J. M. Finn, M. Poelker, R. Neveling, J. Grames, D. T. Spayde, J. Arvieux, J. W. Martin, R. Asaturyan, C. Yan, S. Kox, Douglas H Beck, G. A. Rutledge, A. Kolarkar, J. Yun, R. D. McKeown, Raphael Noel Tieulent, L. Hannelius, P. M. King, S. K. Phillips, A. S. Biselli, D. S. Dale, I. Nakagawa, W. F. Vulcan, Subhasis Chattopadhyay, J. A. Secrest, J. Roche, V. Zeps, M. K. Jones, S. A. Wood, R. Hasty, E. Korkmaz, S. A. Page, Michael Pitt, F. Merchez, S. L. Bailey, C. A. Davis, N. S. Chant, D. S. Armstrong, G. R. Smith, K. Grimm, J. Birchall, S. Ong, S. F. Pate, H. Mkrtchyan, D. Gaskell, R. Clark, T. A. Porcelli, V. Papavassiliou, J. Benesch, A. Lung, M. Stutzman, Jin Liu, P. Bosted, G. B. Franklin, Wolfgang Korsch, A. W. Rauf, R. D. Carlini, B. P. Quinn, V. Tadevosyan, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Thomas Jefferson National Accelerator Facility (Jefferson Lab), and G0
Subjects: electromagnetic processes and properties, media_common.quotation_subject, Elastic electron scattering, Hadron, General Physics and Astronomy, FOS: Physical sciences, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Nuclear physics, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Spin-½, media_common, Physics, Elastic scattering, protons, 010308 nuclear & particles physics, Scattering, neutrons, High Energy Physics - Phenomenology, Amplitude, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], elastic and compton scattering, 25.30.Bf, 13.60.Fz, 13.40.-f, 14.20.Dh, High Energy Physics::Experiment, Atomic physics, Nucleon
Abstract: We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 = 0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the 2-gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments., 5 pages, 3 figures, submitted to Physical Review Letters; shortened to meet PRL length limit, clarified some text after referee's comments
Published: 2007
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32. Recoil polarization measurements for neutral pion electroproduction atQ2=1(GeV/c)2near the Δ resonance

Author: Stephanie Escoffier, C. Cavata, S. McAleer, G. M. Huber, F. Garibaldi, T. Botto, Bogdan Wojtsekhowski, A. Hotta, X. Zheng, J. P. Chen, M. Potokar, G. M. Urciuoli, A. J. Sarty, S. Širca, S. Strauch, M. Coman, C. C. Chang, Ronald Ransome, D. J. Margaziotis, G. Kumbartzki, R. Roche, John C. Mitchell, H. Breuer, Alexei V. Klimenko, D. Crovelli, J. R. Calarco, E. J. Beise, A. Saha, M. Rvachev, H. F. Ibrahim, R. W. Lourie, E. Burtin, L. Todor, R. Suleiman, W. U. Boeglin, L. Lagamba, L. Zhu, K. Wijsooriya, Sonja Dieterich, G. J. Lolos, N. Liyange, E. J. Brash, R. Michaels, Fatiha Benmokhtar, P. G. Roos, J. O. Hansen, Charles Glashausser, James J. Kelly, Shalev Gilad, P. E. Ulmer, S. Georgakopoulos, C. W. de Jager, K. A. Aniol, N. S. Chant, V. Garde, Olivier Gayou, Z. Chai, Kevin Fissum, J. A. Templon, A. Kozlov, C. F. Perdrisat, R. A. Lindgren, J. J. LeRose, S. Frullani, B. D. Milbrath, T. Pussieux, X. Jiang, Mauro Iodice, Larry Weinstein, F. Marie, William Bertozzi, Pete Markowitz, R. De Leo, G. Laveissière, D. Neyret, D. Meekins, V. A. Punjabi, Douglas Higinbotham, M. K. Jones, E. Brown, M. Kuss, J. Nappa, and Ronald Gilman
Subjects: Physics, Scattering cross-section, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Polarization (waves), 01 natural sciences, Nuclear physics, Pion, Recoil, 0103 physical sciences, Quadrupole, High Energy Physics::Experiment, Atomic physics, 010306 general physics, Multipole expansion, Legendre polynomials, Excitation
Abstract: We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q(2)=1.0 (GeV/c)(2) in 10 bins of 1.17 M-Delta. We performed a multipole analysis that adjusts suitable subsets of center dot(pi) Delta quadrupole ratios are not negligible. Parabolic fits to the W dependence around M-Delta for the multiple analysis gives values for Re(S1+/M1+)=(-6.61 +/- 0.18)% and Re(E1+/M1+)=(-2.87 +/- 0.19)% for the p pi(0) channel at W=1.232 GeV and Q(2)=1.0 (GeV/c)(2) that are distinctly larger than those from the Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+)=(+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe.
Published: 2007
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33. Determination of the Pion Charge Form Factor atQ2=1.60and2.45 (GeV/c)2

Author: P. E. Reimer, L. G. Tang, J. Reinhold, V. Tvaskis, S. Jin, V. A. Punjabi, M. K. Jones, D. G. Meekins, Y. Okayasu, A. Matsumura, C. F. Perdrisat, Brynle Barrett, Jin Liu, W. F. Vulcan, W. Kim, M. E. Christy, J. Arrington, Pete Markowitz, A. J. Sarty, T. Horn, E. J. Brash, G. R. Smith, S. Vidakovic, H. P. Blok, V. Tadevosyan, J. Roche, G. M. Huber, K. A. Aniol, V. Kovaltchouk, H. Mkrtchyan, Toshinobu Miyoshi, D. Gaskell, C. Xu, X. Zheng, G. J. Lolos, Lubomir Pentchev, Rolf Ent, J. Volmer, E. J. Beise, E. F. Gibson, W. U. Boeglin, P. G. Roos, D. J. Margaziotis, I. Niculescu, Glen A. Warren, D. H. Potterveld, P. M. King, H. Breuer, C. E. Keppel, C. C. Chang, R. J. Holt, S. A. Wood, and D. J. Mack
Subjects: Physics, Quantum chromodynamics, Particle physics, 010308 nuclear & particles physics, High Energy Physics::Lattice, Nuclear Theory, Form factor (quantum field theory), General Physics and Astronomy, Charge (physics), Regge calculus, 01 natural sciences, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, 010306 general physics, Nucleon, Free parameter
Abstract: The 1H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F(pi)) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F(pi) is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative quantum chromodynamics prediction.
Published: 2006
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34. Determination of the pion charge form factor at Q2=1.60 and 2.45 (GeV/c)2

Author: T, Horn, K, Aniol, J, Arrington, B, Barrett, E J, Beise, H P, Blok, W, Boeglin, E J, Brash, H, Breuer, C C, Chang, M E, Christy, R, Ent, D, Gaskell, E, Gibson, R J, Holt, G M, Huber, S, Jin, M K, Jones, C E, Keppel, W, Kim, P M, King, V, Kovaltchouk, J, Liu, G J, Lolos, D J, Mack, D J, Margaziotis, P, Markowitz, A, Matsumura, D, Meekins, T, Miyoshi, H, Mkrtchyan, I, Niculescu, Y, Okayasu, L, Pentchev, C, Perdrisat, D, Potterveld, V, Punjabi, P, Reimer, J, Reinhold, J, Roche, P G, Roos, A, Sarty, G R, Smith, V, Tadevosyan, L G, Tang, V, Tvaskis, S, Vidakovic, J, Volmer, W, Vulcan, G, Warren, S A, Wood, C, Xu, and X, Zheng
Abstract: The 1H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F(pi)) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F(pi) is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative quantum chromodynamics prediction.
Published: 2006

35. Recoil polarization for delta excitation in pion electroproduction

Author: Olivier Gayou, M. Coman, Bogdan Wojtsekhowski, A. Hotta, D. Crovelli, J. A. Templon, H. F. Ibrahim, D. J. Margaziotis, E. J. Brash, E. Burtin, William Bertozzi, A. Kozlov, G. M. Huber, F. Garibaldi, J. O. Hansen, Stephanie Escoffier, Pete Markowitz, R. W. Lourie, G. Kumbartzki, J. R. Calarco, R. De Leo, G. J. Lolos, Fatiha Benmokhtar, R. Roche, J. P. Chen, Charles Glashausser, Alexei V. Klimenko, B. D. Milbrath, Shalev Gilad, C. W. de Jager, M. Potokar, G. M. Urciuoli, D. Meekins, Ronald Ransome, K. A. Aniol, V. A. Punjabi, H. Breuer, Douglas Higinbotham, Kevin Fissum, M. K. Jones, E. J. Beise, Mauro Iodice, Larry Weinstein, F. Marie, C. C. Chang, S. McAleer, W. U. Boeglin, L. Todor, John C. Mitchell, K. Wijesooriya, E. Brown, R. Michaels, S. Frullani, S. Širca, Sonja Dieterich, S. Strauch, M. Kuss, R. Suleiman, Nilanga Liyanage, L. Lagamba, L. Zhu, P. G. Roos, P. E. Ulmer, C. Cavata, J. Nappa, R. A. Lindgren, Ronald Gilman, A. J. Sarty, J. J. LeRose, X. Zheng, James J. Kelly, N. S. Chant, V. Garde, Z. Chai, C. F. Perdrisat, D. Neyret, G. Laveissière, S. Georgakopoulus, M. Rvachev, T. Pussieux, X. Jiang, T. Botto, A. Saha, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and HALL A
Subjects: Quantum chromodynamics, Physics, 010308 nuclear & particles physics, FOS: Physical sciences, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Polarization (waves), 01 natural sciences, 14.20.Gk,13.60.Le,13.40.Gp,13.88.+e, Nuclear physics, Pion, Amplitude, Recoil, 0103 physical sciences, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), 010306 general physics, Multipole expansion, Nuclear Experiment, Legendre polynomials, Excitation
Abstract: We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q^2=1.0 (GeV/c)^2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re(S1+/M1+)=-(6.84+/-0.15)% and Re(E1+/M1+)=-(2.91+/-0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and sp truncation., 5 pages, 2 figures, for PRL
Published: 2005
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36. Electroproduction of strangeness on [sub Λ][sup 3,4]H bound states on Helium

Author: A. Lung, L. Cole, Rolf Ent, A. Yu. Semenov, D. S. Brown, A. Cochran, H. E. Jackson, John C. Mitchell, R. Asaturyan, K. Gustafsson, Joerg Reinhold, H. C. Fenker, K. Garrow, J. Roche, T. Eden, J. Crowder, P. E. Reimer, G. Collins, Pete Markowitz, Thomas O'Neill, S. A. Wood, H. Breuer, W. Hinton, J.-O. Hansen, Brian Raue, J. A. Dunne, L. A. Ewell, F. Dohrmann, A. Uzzle, P. Ambrozewicz, C. J. Martoff, I. Niculescu, J. W. Price, D. J. Mack, H. Bitao, C. Yan, M. Sarsour, E. Christy, D. H. Potterveld, M. Elaasar, Paul Gueye, A. Ahmidouch, S. Beedoe, L. G. Tang, D. F. Geesaman, Stephen Avery, F. Duncan, H. Mkrtchyan, C. Cothran, R. Sawafta, Y. Liang, L. Yuan, S. Stepanyan, B. Zihlmann, P. G. Roos, Avraham Klein, S. Mtingwa, R. E. Segel, M. Zeier, Kevin Bailey, J. H. Liu, V. Tadevosian, J. Cha, B. Terburg, S. Tajima, R. Mohring, D. G. Meekins, R. Madey, Dipangkar Dutta, N. S. Chant, S. Danagoulian, H. Juengst, G. Savage, C. E. Keppel, G. Niculescu, Ketevi Assamagan, R. D. Carlini, B. Mueller, L. Gan, W. J. Cummings, H. Yamaguchi, J. Arrington, C. S. Armstrong, D. Abbott, D. Koltenuk, Y. Fujii, Haiyan Gao, B. Zeidman, Toshinobu Miyoshi, Yoichi Sato, H. T. Fortune, and K. Hafidi
Subjects: Physics, Particle physics, chemistry.chemical_element, Particle accelerator, Strangeness, Lambda baryon, Lambda, law.invention, Nuclear physics, Helium-4, chemistry, law, Helium-3, Bound state, Helium
Abstract: The A(e,e'K+)X reaction has been investigated at Jefferson Laboratory. Data were taken for Q2 {approx_equal} 0.35 GeV2 at a beam energy of 3.245 GeV for 1H,3He and 4He targets. Evidence for {lambda}-hypernuclear bound states is seen for 3,4He targets. This is the first time that the electroproduction of these hypernuclei has been observed.
Published: 2005
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37. Near threshold electroproduction of theωmeson atQ2≈0.5GeV2

Author: L. Ewell, J. Arrington, D. Abbott, S. Danagoulian, J. A. Dunne, John C. Mitchell, D. G. Meekins, Brian Raue, T. Eden, J.-O. Hansen, J. Reinhold, H. Mkrtchyan, H. T. Fortune, Dipanwita Dutta, L. G. Tang, V. Tadevosyan, Oliver Keith Baker, R. Sawafta, G. Niculescu, C. Cothran, Richard Madey, B. Zihlmann, D. H. Potterveld, Kevin Bailey, B. Zeidman, Ketevi Assamagan, R. D. Carlini, Andreas Klein, Donal Day, B. Terburg, J. W. Price, Pete Markowitz, J. Cha, C. Yan, C. S. Armstrong, W. J. Cummings, D. Koltenuk, A. Ahmidouch, K. Gustafsson, F. Duncan, G. Collins, Thomas O'Neill, I. Niculescu, Rolf Ent, G. Savage, Haiyan Gao, W. Hinton, Paul Gueye, D. F. Geesaman, S. A. Wood, S. Stepanyan, P. G. Roos, H. Breuer, D. J. Mack, C. E. Keppel, R. E. Segel, R. Mohring, S. Beedoe, S. Mtingwa, P. Ambrozewicz, and C. J. Martoff
Subjects: Physics, Nuclear and High Energy Physics, Angular range, Particle physics, Photon, Meson production, Meson, 010308 nuclear & particles physics, Parity (physics), 01 natural sciences, Omega, Nuclear physics, Near threshold, Angular distribution, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: Electroproduction of the {omega} meson was investigated in the {sup 1}H(e,e{sup '}p){omega} reaction. The measurement was performed at a four-momentum transfer Q{sup 2}{approx_equal}0.5 GeV{sup 2}. Angular distributions of the virtual photon-proton center-of-momentum cross sections have been extracted over the full angular range. These distributions exhibit a strong enhancement over t-channel parity exchange processes in the backward direction. According to a newly developed electroproduction model, this enhancement provides significant evidence of resonance formation in the {gamma}*p{yields}{omega}p reaction channel.
Published: 2004
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38. Measurements of electron-proton elastic cross sections for0.4<Q2<5.5(GeV∕c)2

Author: R. Asaturyan, B. Mueller, L. Cole, D. Gaskell, A. Lung, Pete Markowitz, B. D. Fox, Rolf Ent, D. Meekins, D. S. Brown, A. Gasparian, A. Cochran, J. A. Dunne, H. Breuer, Ronald Ransome, A. J. Sarty, Ross Milner, John Arrington, C. E. Keppel, L. Gan, J. W. Martin, K. Garrow, R. D. Carlini, M. Harvey, A. Bruell, G. Niculescu, E. Schulte, H. P. Blok, R. J. Holt, Paul Gueye, W. U. Boeglin, D. F. Geesaman, N. S. Chant, S. A. Wood, Wolfgang Lorenzon, J. Reinhold, S. Strauch, Curtis Smith, Raphael Noel Tieulent, S. Stepanyan, P. G. Roos, X. Jiang, M. Bouwhuis, S. F. Pate, H. Mkrtchyan, C. Bochna, L. Yuan, M. A. Miller, Thomas O'Neill, A. Uzzle, Stephen Avery, M. Zeier, V. Tadevosyan, C. S. Armstrong, E. Rollinde, V. Papavassiliou, Dipanwita Dutta, O. K. Baker, P. Bosted, Haiyan Gao, I. Niculescu, Alan M. Nathan, E. R. Kinney, L. G. Tang, M. E. Christy, V. Ziskin, B. Zihlmann, R. Sawafta, F. Xiong, Douglas H Beck, Y. Liang, A. Ahmidouch, E. Segbefia, H. C. Fenker, K. McIlhany, J. H. Mitchell, D. H. Potterveld, W. F. Vulcan, R. B. Piercey, S. Danagoulian, D. McKee, and Donal Day
Subjects: Systematic error, Physics, Nuclear and High Energy Physics, Range (particle radiation), Proton, 010308 nuclear & particles physics, Scattering, Momentum transfer, Electron, Polarization (waves), 01 natural sciences, Nuclear physics, Cross section (physics), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract: We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 distinct kinematic settings covering a range in momentum transfer of 0.4
Published: 2004
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39. Basic instrumentation for Hall A at Jefferson Lab

Author: T. Pussieux, Paul Souder, J. H. Mitchell, Y. Roblin, O. Ravel, E. Chudakov, K. A. Griffioen, C. Cavata, J. A. Templon, H. F. Ibrahim, J. S. McCarthy, M. A. Stevens, D. P. Watts, B. Frois, W. J. Schneider, Dipangkar Dutta, R. Di Salvo, R. I. Pomatsalyuk, A. Soldi, G. J. Kumbartzki, Arijit Saha, N. Colombel, J. Berthot, Jing Zhao, A. J. Sarty, B. D. Anderson, J. Martine, M. Coman, R. Michaels, M. B. Epstein, R. W. Lourie, J. O. Hansen, N. Degrande, J. Mclntyre, John Arrington, L. Zhu, W. Kahl, Bogdan Wojtsekhowski, P. Djawotho, M. Leuschner, William Bertozzi, K. A. Aniol, A. Gasparian, Karl Slifer, Jrm Annand, C. F. Perdrisat, D. Pripstein, M. Baylac, S. Kox, X. Jiang, K. Kramer, H. Breuer, David Hamilton, Jian-Ping Chen, T. Averett, L. B. Auerbach, G. A. Rutledge, G. Quéméner, Stephanie Escoffier, P.Y. Bertin, R. Suleiman, R. Carr, Pete Markowitz, A. Deur, Z. Papandreou, R. L. Walter, R. D. McKeown, T. P. Gorringe, M. Rvachev, R. Holmes, S. Churchwell, J. Marroncle, S. Platchkov, M. Khandaker, M. Liang, L. Pierangeli, K. Kino, A. Ketikyan, Kevin Fissum, F. W. Hersman, J. LeRose, F. Giuliani, P. E. Ulmer, Roberto Perrino, R. De Leo, J. Gao, L. A. Ewell, S. Jensen, R. Crateri, Shalev Gilad, C. W. de Jager, D. Lhuillier, J.E. Ducret, M. Gricia, R. Iommi, F. Sabatavenere, P. A. Zolnierczuk, K. Wijesooriya, Alan M. Nathan, D. Rowntree, E. Voutier, H. Holmgren, S. K. Nanda, D. G. Meekins, K. S. Egiyan, C. R. Howell, A. Serdarevic-Offermann, Hiroaki Tsubota, D. G. Zainea, J. R. Calarco, S. Esp, T. Terasawa, Vincent Breton, C. C. Chang, J. Domingo, T. Black, A. T. Katramatou, S. Kerhoas, F. Santavenere, J. Y. Mougey, R. Van de Vyver, G. M. Urciuoli, Seigo Kato, G. M. Huber, B. Reitz, E. J. Beise, K. S. Kumar, F. Garibaldi, Pavel Sorokin, G. J. Lolos, M. Lucentini, J. Segal, H. Xiang, D. V. Boykin, W. U. Boeglin, C. Glashausser, E. Cisbani, A. Leone, R. D. Ransomez, Gordon D. Cates, Sonja Dieterich, H. Voskanyan, C. Jutier, R. L.J. van der Meer, Olivier Gayou, James A. Miller, L. Van Hoorebeke, Sebastien Incerti, J. Jardillier, L. Cardman, James J. Kelly, F. Xiong, S. Jaminion, I. K. Kominis, K. McCormick, P. Vernin, P. M. Rutt, A. Petrosyan, David L. Prout, Nilanga Liyanage, L. Lagamba, X. Zheng, S. L. Spiegel, Branislav Vlahovic, Leonid Levchuk, Mauro Iodice, Larry Weinstein, F. Marie, D. G. Ireland, N. S. Chant, David Manley, V. A. Punjabi, C. E. Jones, J. Gomez, Wolfgang Korsch, W. Xu, J. W. Watson, M. Roedelbronn, F. T. Baker, Z. E. Meziani, T. Saito, S. Frullani, H. Ueno, E. J. Brash, R. Roche, E. Hovhannisyan, C. E. Hyde-Wright, N. d'Hose, L. Bimbot, G. Laveissière, R. Madey, Kazushige Maeda, A. Gavalya, W. Miller, D. Neyret, T. P. Smith, B. Diederich, E. Burtin, M. Holtrop, L. Todor, G. Dezern, Z. L. Zhou, K. Livingston, D. S. Dale, V. Zeps, S. Mayilyan, E. Folts, B. D. Milbrath, Haiyan Gao, J. M. Finn, O. Rondon-Aramayo, R. A. Lindgren, V. Gorbenko, A. V. Glamazdin, Z. Chai, E. A.J.M. Offermann, S. Malov, J. Alcorn, S. Strauch, A. Shahinyan, G. Rosner, H. Fonvieille, P. G. Roos, E. W. Hughes, K. Joo, D. S. Brown, P. Brindza, G. G. Petratos, S. van Verst, M. Khayat, S. Colilli, Douglas Higinbotham, M. K. Jones, D. J. Margaziotis, M. Kuss, Seonho Choi, Ronald Gilman, Thomas Jefferson National Accelerator Facility (Jefferson Lab), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), HALL A, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, Cryogenics, Scintillator, 7. Clean energy, 01 natural sciences, Particle identification, Magnetic field, Nuclear physics, Cardinal point, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Nuclear Experiment, 010306 general physics, Nucleon, Instrumentation, Cherenkov radiation
Abstract: The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
Published: 2004
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40. Light-ion elastic scattering potentials: Energy and projectile-mass dependence

Author: P. Schwandt, P. G. Roos, S. Balaji, A. Nadasen, K. A. G. Rao, J. T. Ndefru, and J. Brace
Subjects: Elastic scattering, Physics, Nuclear and High Energy Physics, Projectile, Nuclear Theory, Volume integral, Ion, symbols.namesake, Pauli exclusion principle, Isospin, symbols, Atomic physics, Nuclear Experiment, Nucleon, Energy (signal processing)
Abstract: Volume integrals of the real potentials derived from elastic scattering studies of deuterons, tritons, ${}^{3}\mathrm{He},$ and $\ensuremath{\alpha}$ particles have been calculated for data available from the lowest to the highest energy. These volume integrals have been plotted as a function of energy per nucleon for each projectile. By selecting energy regions where there were least ambiguities in the potentials and averaging the volume integrals in 1 MeV bins, the energy dependences were determined. The volume integrals show a logarithmic dependence on the energy per nucleon. The zero crossing of the potentials is at about the same value of $\ensuremath{\sim}650\mathrm{MeV}/$nucleon for all projectiles. With increasing projectile mass, the potentials become weaker, possibly due to Pauli blocking effects in the projectile. Neutron-rich projectiles have smaller volume integrals due to the manifestation of the isospin effect. A similar analysis of the imaginary volume integrals shows that they increase from zero at the lowest energies to about $100\char21{}150{\mathrm{MeV}\mathrm{}\mathrm{fm}}^{3}$ around $10\mathrm{MeV}/$nucleon and then remain essentially constant.
Published: 2003
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41. Separation of the longitudinal and transverse cross sections in the1H(e,e′K+)Λand1H(e,e′K+)Σ0reactions

Author: A. Ahmidouch, M. Harvey, S. Beedoe, T. P. Welch, John C. Mitchell, T. Eden, M. Maeda, S. Frullani, F. Duncan, A. F. Lung, K. Gustafsson, K. Kino, S. A. Wood, Paul Gueye, D. F. Geesaman, M. Finn, W. F. Vulcan, Brian Raue, Ts A. Amatuni, Guido Urciuoli, S. Mtingwa, J. A. Dunne, Christophe Furget, D. J. Mack, P. Ambrozewicz, F. Garibaldi, P. Stoler, V. Tadevosian, Kevin Bailey, H. Breuer, Stephen Avery, V. Frolov, H. Mkrtchyan, Terry Mart, T. Saito, D. Abbott, C. Yan, D. Koltenuk, C. C. Chang, S. Stepanyan, P. G. Roos, C. E. Keppel, W. Hinton, S. Danagoulian, W. Kim, J. Cha, Dipangkar Dutta, D. H. Potterveld, Rolf Ent, A. Mihul, G. Collins, D. G. Meekins, J. Arrington, E. V. Hungerford, C. S. Armstrong, E. Cisbani, L. Eyraud, R. Perrino, W. J. Cummings, Laird Kramer, J. Volmer, Hiroaki Tsubota, L. A. Ewell, E. J. Beise, S. Majewski, T. Angelescu, S. Kox, R. E. Segel, C. J. Martoff, B. Zeidman, G. Savage, Mauro Iodice, T. Terasawa, K. Beard, D. Gaskell, R. Mohring, L. Teodorescu, C. Jackson, R. Williams, J.-O. Hansen, I. Niculescu, Pete Markowitz, J. S. Real, R. De Leo, R. Madey, R. D. Carlini, J. W. Price, L. G. Tang, R. Sawafta, N. S. Chant, Ketevi Assamagan, J. Reinhold, T. Leone, and T. Fortune
Subjects: Physics, Nuclear and High Energy Physics, Meson production, 010308 nuclear & particles physics, Hyperon, Virtual particle, Lambda, 01 natural sciences, Transverse plane, 0103 physical sciences, Invariant mass, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract: We report measurements of cross sections for the reaction ${}^{1}\mathrm{H}{(e,e}^{\ensuremath{'}}{K}^{+})Y,$ for both the \ensuremath{\Lambda} and ${\ensuremath{\Sigma}}^{0}$ hyperon states, at an invariant mass of $W=1.84\mathrm{GeV}$ and four-momentum transfers $0.5l{Q}^{2}l2(\mathrm{GeV}{/c)}^{2}.$ Data were taken for three values of virtual photon polarization $\ensuremath{\epsilon},$ allowing the decomposition of the cross sections into longitudinal and transverse components. The \ensuremath{\Lambda} data are a revised analysis of prior work, whereas the ${\ensuremath{\Sigma}}^{0}$ results have not been previously reported.
Published: 2003
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42. ELECTROPRODUCTION OF STRANGENESS ON LIGHT NUCLEI

Author: R. Carlini, M. Elaasar, F. Dohrmann, I. Niculescu, H. E. Jackson, G. Savage, H. Yamaguchi, J. Roche, H. G. Juengst, S. A. Wood, S. Danagoulian, D. Abbott, Paul Gueye, T. Eden, G. Niculescu, M. Zeier, M. Sarsour, C. J. Martoff, L. Cole, Stephen Avery, R. E. Segel, J. Crowder, Y. Liang, B. Terburg, P. G. Roos, Avraham Klein, H. Mkrtchyan, Rolf Ent, Ketevi Assamagan, S. Beedoe, Cynthia Keppel, P. E. Reimer, J. W. Price, Y. Fujii, B. Zeidman, R. Mohring, O. K. Baker, D. Koltenuk, J. H. Liu, R. Asaturyan, J. H. Mitchell, H. Bitao, P. Ambrozewicz, N. Chant, A. Ahmidouch, W. Hinton, B. Zihlmann, D. G. Meekins, D. F. Geesaman, S. Mtingwa, A. Uzzle, T. Miyoshi, V. Tadevosian, K. Gustafsson, S. S. Stepanyan, David Mack, L. G. Tang, R. Sawafta, Kevin Bailey, C. S. Armstrong, Chenyu Yan, L. Yuan, D. H. Potterveld, E. Christy, C. Cothran, P. Markowitz, L. Gan, A. Yu. Semenov, W. J. Cummings, G. Collins, F. Duncan, Thomas O'Neill, Joerg Reinhold, K. Garrow, A. Lung, J. Cha, Dipangkar Dutta, R. Madey, D. S. Brown, A. Cochran, J. Arrington, J. O. Hansen, Haiyan Gao, James Dunne, H. Fenker, B. Mueller, Yoichi Sato, H. Breuer, H. T. Fortune, B. A. Raue, K. Hafidi, S. Tajima, and L. A. Ewell
Subjects: Nuclear physics, Physics, Light nucleus, Strangeness
Published: 2003
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43. Separated response functions in exclusive, forward pi(+/-) electroproduction on deuterium

Author: L. Pentchev, L. G. Tang, S. Jin, D. van Westrum, D. G. Meekins, C. C. Chang, John C. Mitchell, C. Yan, H. C. Fenker, E. J. Beise, P. E. Reimer, G. M. Huber, John Arrington, W. U. Boeglin, P. M. King, G. R. Smith, D. Koltenuk, X. Zheng, D. J. Margaziotis, V. Kovaltchouk, H. P. Blok, B. Mueller, S. A. Wood, T. Eden, W. Hinton, M. Liang, Ketevi Assamagan, D. McKee, Joerg Reinhold, A. J. Sarty, V. Tvaskis, S. Vidakovic, V. Tadevosyan, R. J. Holt, W. F. Vulcan, D. J. Mack, L. M. Qin, C. S. Armstrong, Stephen Avery, Ronald Gilman, I. K. Shin, D. Abbott, K. A. Aniol, B. Zihlmann, C. E. Keppel, P. H. Kim, W. Zhao, J. Volmer, Y. Okayasu, D. H. Potterveld, H. E. Jackson, M. K. Jones, E. J. Brash, G. J. Lolos, J. Roche, H. Breuer, Tanja Horn, R. L.J. van der Meer, K. Vansyoc, C. Butuceanu, H. Anklin, C. Xu, D. Gaskell, N. S. Chant, D. Pitz, C. Bochna, I. Niculescu, Glen A. Warren, K. Gustafsson, E. F. Gibson, S. Stepanyan, H. Mkrtchyan, P. G. Roos, Avraham Klein, A. Matsumura, O. K. Baker, A. Lung, T. Miyoshi, C. F. Perdrisat, Rolf Ent, Jin Liu, M. E. Christy, W. Kim, G. Niculescu, Pete Markowitz, J. A. Dunne, B. Barrett, V. A. Punjabi, and Student Lab and Education
Subjects: Quantum chromodynamics, Quark, Physics, Nuclear and High Energy Physics, Particle physics, SDG 16 - Peace, Meson, Isoscalar, SDG 16 - Peace, Justice and Strong Institutions, Form factor (quantum field theory), Virtual particle, Parton, Justice and Strong Institutions, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment
Abstract: Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in $\pi^-$ and $\pi^+$ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at W=1.95 GeV, and $Q^2$=2.45 GeV$^2$ at W=2.22 GeV. There was significant coverage in $\phi$ and $\epsilon$, which allowed separation of $\sigma_{L,T,LT,TT}$. Results: $\sigma_L$ shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, $\sigma_T$ is much flatter versus t. The longitudinal/transverse ratios evolve with $Q^2$ and t, and at the highest $Q^2$=2.45 GeV$^2$ show a slight enhancement for $\pi^-$ production compared to $\pi^+$. The $\pi^-/\pi^+$ ratio for transverse photons exhibits only a small $Q^2$-dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The $\sigma_{TT}/\sigma_T$ ratio also drops rapidly with $Q^2$, qualitatively consistent with s-channel helicity conservation. The $\pi^-/\pi^+$ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics., Comment: 25 pages, 16 figures, 6 tables
Published: 2015
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44. Nucleon elastic scattering potentials: Energy and isospin dependence

Author: J. Brace, P. G. Roos, K. A. G. Rao, J. T. Ndefru, P. Schwandt, S. Balaji, and A. Nadasen
Subjects: Physics, Elastic scattering, Nuclear and High Energy Physics, Quasielastic scattering, Nuclear Theory, Scattering length, Neutron scattering, Inelastic scattering, Small-angle neutron scattering, Nuclear physics, Isospin, Physics::Accelerator Physics, Neutron, Nuclear Experiment
Abstract: Volume integrals of the real potentials derived from proton elastic scattering studies have been calculated for data available from the lowest to the highest energy. Because of the spread of the volume integrals at low energies, an average of volume integrals in each 1 MeV bin was calculated. These average volume integrals show a logarithmic dependence on the beam energy. A similar analysis of neutron potentials shows that the proton energy dependence can be applied to neutron data. The data for proton scattering from Ca isotopes at 1044 MeV were analyzed in terms of the optical model, and an isospin component of the potential was determined. The derived isospin potential is compared with those obtained for proton and neutron scattering in previous investigations.
Published: 2002
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45. Measurement of longitudinal and transverse cross sections in the3He(e,e′π+)3Hreaction atW=1.6 GeV

Author: J. Cha, Dipangkar Dutta, I. Niculescu, D. McKee, V. Tadevosyan, B. Mueller, Kevin Bailey, J. Arrington, B. Beise, P. Ambrozewicz, B. Zihlmann, D. Schepper, S. A. Wood, H. Breuer, J. A. Dunne, Toshiyuki Takahashi, H. Mkrtchyan, B. Terburg, R. D. Carlini, L. Gan, D. J. Mack, Paul Gueye, L. G. Tang, D. H. Potterveld, D. F. Geesaman, Ketevi Assamagan, Stephen Avery, R. Sawafta, R. E. Segel, N. S. Chant, John C. Mitchell, T. P. Welch, S. Stepanyan, P. G. Roos, D. Gaskell, V. Papavassiliou, C. Jackson, G. Hofman, B. Zeidman, Thomas O'Neill, C. E. Keppel, C. Glashausser, A. Lung, M. Harvey, J. Reinhold, Rolf Ent, D. Koltenuk, D. S. Brown, S. Beedoe, A. Gasparian, J. Volmer, A. A. Cowley, Osamu Hashimoto, H. E. Jackson, O. K. Baker, H. Anklin, A. Ahmidouch, L. Yuan, E. R. Kinney, D. van Westrum, S. Danagoulian, G. Niculescu, W. Hinton, and Ronald Gilman
Subjects: Physics, Nuclear and High Energy Physics, Meson production, Photon, Nuclear Theory, Virtual particle, Polarization (waves), Nuclear physics, Transverse plane, Pion, Pi, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Nucleon
Abstract: The coherent 3He(e,e{pi}+)3H reaction was measured at Q2 = 0.4 (GeV/c)2 and W = 1.6 GeV for two values of the virtual photon polarization, {epsilon}, allowing the separation of longitudinal and transverse cross sections. The results from the coherent process on 3He were compared to H(e,e{pi}+)n data taken at the same kinematics. This marks the first direct comparison of these processes. At these kinematics (p{pi} = 1.1 GeV/c), pion rescattering from the spectator nucleons in the 3He(e,e{pi}+)3H process is expected to be small, simplifying the comparison to {pi}+ production from the free proton.
Published: 2001
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46. Analyzing power reduction in quasifree pion-nucleon knockout reactions

Author: T. A. Greco, F. Adimi, R. Meier, B. S. Flanders, B. van den Brandt, Thomas H. Chang, James J. Kelly, A. P. Dvoredsky, J. A. Konter, M. Khayat, N. S. Chant, J. Huffman, M.H. Wang, Z. N. Lin, S. Kovalev, G. S. Kyle, T. Dooling, K. Koch, T. Payerle, J. Lawrie, H. Breuer, T. Gu, P. G. Roos, Avraham Klein, S. Ritt, and S. Mango
Subjects: Nuclear physics, Physics, Reduction (complexity), Nuclear and High Energy Physics, Pion, Quantum electrodynamics, Nucleon, Power (physics)
Published: 2001
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47. Measurement of the Electric Form Factor of the Neutron throughd→(e→,e′n)patQ2=0.5(GeV/c)2

Author: T Petitjean, C. Yan, John C. Mitchell, M Mühlbauer, V. Tadevosyan, W. F. Vulcan, A Honegger, Pete Markowitz, M. Khandaker, S. Danagoulian, M. Hauger, H Wöhrle, G Milanovich, B. Zihlmann, Hartmuth Arenhövel, M Kaufmann, S Bültmann, R Lourie, G Kubon, A Cowley, C Bernet, H. Mkrtchyan, T Eden, H Anklin, O. Rondon, P Brindza, Y Farah, E Rollinde, T Southern, Donal Day, R. D. Carlini, R. Sawafta, K McFarlane, M. Zeier, R. Fatemi, S Malik, Daniela Rohe, Curtis Smith, J Zhao, Raphael Noel Tieulent, Rolf Ent, D. S. Brown, A Tobias, R. A. Lindgren, Glen A. Warren, S. A. Wood, W.U. Boeglin, S. Stepanyan, P. G. Roos, D. J. Mack, N. S. Chant, J. Lichtenstadt, Ingo Sick, C Harris, M. Steinacher, H. Breuer, Hongbo Zhu, K. Garrow, A. Ahmidouch, J. Jourdan, Y. Prok, D. McNulty, A. F. Lung, D. G. Crabb, P. McKee, and C. S. Armstrong
Subjects: Physics, Scattering, Momentum transfer, Electric form factor, General Physics and Astronomy, Particle accelerator, Electron, Polarization (waves), law.invention, Nuclear physics, Deuterium, law, High Energy Physics::Experiment, Neutron, Atomic physics, Nuclear Experiment
Abstract: We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).
Published: 2001
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48. Quasifree subthreshold pion production in the reactionC12(p,dπ+)11B

Author: S. V. Förtsch, J. V. Pilcher, G. C. Hillhouse, G.F. Steyn, P. G. Roos, A. A. Cowley, J. J. Lawrie, and F. D. Smit
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Particle physics, Reaction mechanism, Nuclear Theory, Isotopes of boron, Charged particle, Pion, Deuterium, Elementary reaction, Pi, Atomic physics, Nuclear Experiment
Abstract: Nuclear pion production has been studied by means of the reaction $^{12}\mathrm{C}$(p,d${\mathrm{\ensuremath{\pi}}}^{+}$${)}^{11}$B at an incident energy of 223 MeV, which is considerably below the threshold for a free N-N process. The shape and absolute cross section of the experimental energy-sharing distribution are in remarkable agreement with the prediction of a distorted-wave impulse approximation theory. This shows that the reaction mechanism is quasifree pion production, which is related to the elementary reaction p+p\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{+}$+d.
Published: 1992
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49. 4He+4Heelastic scattering at 280 and 620 MeV

Author: W. Yuhasz, K. A. G. Rao, A. Nadasen, P. G. Roos, Daniel R. Sisan, Sam M. Austin, R. E. Warner, and D. J. Mercer
Subjects: Nuclear physics, Physics, Elastic scattering, Nuclear and High Energy Physics, Quasielastic scattering, symbols.namesake, Quasielastic neutron scattering, symbols, Rutherford scattering, Inelastic scattering, Mott scattering
Published: 2000
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50. Measurement of Tensor Polarization in Elastic Electron-Deuteron Scattering at Large Momentum Transfer

Author: D. Abbott, A. Ahmidouch, H. Anklin, J. Arvieux, J. Ball, S. Beedoe, E. J. Beise, L. Bimbot, W. Boeglin, H. Breuer, P. Brindza, R. Carlini, N. S. Chant, S. Danagoulian, K. Dow, J.-E. Ducret, J. Dunne, L. Ewell, L. Eyraud, C. Furget, M. Garçon, R. Gilman, C. Glashausser, P. Gueye, K. Gustafsson, K. Hafidi, A. Honegger, J. Jourdan, S. Kox, G. Kumbartzki, L. Lu, A. Lung, D. Mack, P. Markowitz, J. McIntyre, D. Meekins, F. Merchez, J. Mitchell, R. Mohring, S. Mtingwa, H. Mrktchyan, D. Pitz, L. Qin, R. D. Ransome, J.-S. Réal, P. G. Roos, P. Rutt, R. Sawafta, S. Stepanyan, R. Tieulent, E. Tomasi-Gustafsson, W. Turchinetz, K. Vansyoc, J. Volmer, E. Voutier, W. Vulcan, C. Williamson, S. A. Wood, C. Yan, J. Zhao, W. Zhao, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and JLAB t20
Subjects: representation, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Electron, 01 natural sciences, Nuclear physics, Recoil, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, new medias, Spectrometer, 010308 nuclear & particles physics, Scattering, Momentum transfer, Perturbative QCD, Polarization (waves), semiotics, Deuterium, numeric pictures, virtual reality
Abstract: Tensor polarization observables (t20, t21 and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c)^2. The experiment was performed at the Jefferson Laboratory in Hall C using the electron HMS Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q^2 the deuteron charge form factors G_C and G_Q. They are in good agreement with relativistic calculations and disagree with pQCD predictions., 5 pages, 4 figures, for associated informations, see http://isnwww.in2p3.fr/hadrons/t20/t20_ang.html clarification about several topics, one figure has been had, extraction of form factors use AQ interpolation in our Q2 range only
Published: 2000

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