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180 results on '"F. W. Hersman"'

1. High-efficiency resonant rf spin rotator with broad phase space acceptance for pulsed polarized cold neutron beams

Author

P.-N. Seo, L. Barrón-Palos, J. D. Bowman, T. E. Chupp, C. Crawford, M. Dabaghyan, M. Dawkins, S. J. Freedman, T. Gentile, M. T. Gericke, R. C. Gillis, G. L. Greene, F. W. Hersman, G. L. Jones, M. Kandes, S. Lamoreaux, B. Lauss, M. B. Leuschner, R. Mahurin, M. Mason, J. Mei, G. S. Mitchell, H. Nann, S. A. Page, S. I. Penttilä, W. D. Ramsay, A. Salas Bacci, S. Santra, M. Sharma, T. B. Smith, W. M. Snow, W. S. Wilburn, and H. Zhu

Subjects
Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPDGamma experiment, a search for the small parity-violating γ-ray asymmetry A_{γ} in polarized cold neutron capture on parahydrogen, is one example. For the NPDGamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm×9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to rf neutron spin flippers based on adiabatic fast passage. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically polarized ^{3}He neutron spin filters. The efficiency of the spin rotator was measured at LANSCE to be 98.8±0.5% for neutron energies from 3 to 20 meV over the full phase space of the beam. Systematic effects that the rf spin rotator introduces to the NPDGamma experiment are considered.

Published
2008
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2. A path to scaling helium-3 spin-exchange optical pumping

Author

Steve Ketel, S. J. Anderson, Iulian C. Ruset, F. W. Hersman, Jan Distelbrink, David Watt, and Jeffrey Ketel

Subjects
010302 applied physics, Materials science, business.industry, Physics::Optics, General Physics and Astronomy, 02 engineering and technology, Neutron scattering, 021001 nanoscience & nanotechnology, Polarization (waves), Laser, 01 natural sciences, Pressure vessel, law.invention, Optical pumping, law, Helium-3, Metastability, 0103 physical sciences, Thermal, Optoelectronics, 0210 nano-technology, business
Abstract

Polarized 3 He has contributed to breakthroughs in particle physics, neutron scattering, and lung imaging, mostly by optical pumping of liter quantities in valved cells or in sealed cells pumped in situ. Only metastability exchange optical pumping currently meets the demand for delivering large quantities of highly polarized 3 He to external volumes. Our development program is under way to achieve medium to large-scale spin-exchange optical pumping of 3 He. Thin-walled aluminosilicate cells placed in contact with thermal reservoirs inside a pressure vessel were optically pumped with kilowatt-scale lasers spectrally narrowed to match pressure-broadened absorption linewidths. We report here the key elements of this program and significant milestones: multi-liter volume valved cells that provide long longitudinal lifetimes that reached polarization as high as 85% inside a thermally stable and pressurized environment.

Published
2020

3. Status of the NPDGamma experiment

Author

C. Garcia, E. Frlež, E. Askanazi, S. Balascuta, Dinko Pocanic, D. Evans, P. N. Seo, H. Nann, Kyle B. Grammer, M. Musgrave, Gregory S. Mitchell, Bernhard Lauss, R. Mahurin, D. Blyth, F. Simmons, Geoffrey Greene, V.W. Yuan, E. Tang, L. Kabir, S. A. Page, J. R. Calarco, Ricardo Alarcon, C. Hayes, Timothy Chupp, Yi-De Zhang, T. Tong, Erik B. Iverson, C. E. Coppola, L. Barrón-Palos, Alexander Barzilov, W. Fox, Charles Fieseler, I. Garishvili, K. Craycraft, J. Stuart, F. W. Hersman, Y. Li, Z. Tang, M. Sharma, R. Allen, Christopher Crawford, J. Vanderwerp, Gordon L. Jones, P. E. Mueller, J. Hamblen, Yasuhiro Masuda, S. I. Penttilä, Robert Milburn, S. Baeßler, A. Salas-Bacci, C. Fu, D. Parsons, Ivan Novikov, E. I. Sharapov, Takashi Ino, Nadia Fomin, S. Kucucker, Stuart J. Freedman, J. Thomison, W. D. Ramsay, Michael Gericke, C. Blessinger, M. Maldonado-Velázquez, J. Fry, M. Dabaghyan, R. C. Gillis, M. McCrea, S. Waldecker, J. Mei, T. B. Smith, J. D. Bowman, S. Santra, Suguru Muto, W. M. Snow, W. Xu, W. S. Wilburn, and J. Favela

Subjects
Nuclear and High Energy Physics, Particle physics, Meson, media_common.quotation_subject, Nuclear Theory, Hadron, Weak interaction, 01 natural sciences, 7. Clean energy, Asymmetry, Nuclear physics, 0103 physical sciences, Neutron, Physical and Theoretical Chemistry, Nuclear Experiment, 010306 general physics, media_common, Physics, 010308 nuclear & particles physics, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Neutron capture, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon, Spallation Neutron Source
Abstract

The NPDGamma experiment measures the parity-violating (PV) gamma asymmetry from polarized cold neutrons captured on protons at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The (PV) neutron spin asymmetry A γ of photons from polarized cold neutron capture on protons is proportional to the ΔI=1 long range weak meson coupling $h_{\pi }^{1}$ between nucleons in the hadronic weak interaction (HWI). Liquid para-hydrogen production data taking concluded in April 2014 and once the background aluminum asymmetry measurements are complete, the PV asymmetry A γ can be extracted. Preliminary results of the analysis of A γ are presented.

Published
2016

4. Power scaling of a wavelength-narrowed diode laser system for pumping alkali vapors

Author

F. W. Hersman, J. H. Distelbrink, J. Wilson, J. Ketel, and David W. Watt

Subjects
Materials science, business.industry, Physics::Optics, Laser pumping, Laser, 01 natural sciences, law.invention, Semiconductor laser theory, 010309 optics, Laser linewidth, Optics, law, Optical cavity, 0103 physical sciences, Physics::Accelerator Physics, Optoelectronics, Laser power scaling, 010306 general physics, business, Tunable laser, Diode
Abstract

We report a method for locking the output wavelength and reducing the spectral linewidth of diode lasers by feeding back light to the emitters from a wavelength selective external optical cavity. Ten years ago our team developed a stepped-mirror that allowed a single external cavity to lock the wavelength of a stack of diode array bars by equalizing path lengths between each emitter and the grating. Here we report combining one such step-mirror external cavity with an array of power dividers, each sending a portion of this feedback power to a separate diode array bar stack.

Published
2016

5. Hyperpolarized Xenon-129 gas-exchange imaging of lung microstructure: First case studies in subjects with obstructive lung disease

Author

Isabel Dregely, G. Wilson Miller, Kai Ruppert, Steve Ketel, Jaime F. Mata, Jan Distelbrink, John P. Mugler, Iulian C. Ruset, Jeffrey Ketel, Talissa A. Altes, and F. W. Hersman

Subjects
Adult, Male, medicine.medical_specialty, Time Factors, Xenon, Contrast Media, Hyperpolarized Xenon 129, Article, Image Processing, Computer-Assisted, medicine, Isotopes of xenon, Humans, Radiology, Nuclear Medicine and imaging, Lung Diseases, Obstructive, Lung, COPD, Models, Statistical, medicine.diagnostic_test, business.industry, Magnetic resonance imaging, Middle Aged, medicine.disease, Magnetic Resonance Imaging, Obstructive lung disease, medicine.anatomical_structure, Xenon Isotopes, Female, Radiology, Tomography, Tomography, X-Ray Computed, Nuclear medicine, business, Perfusion, Algorithms, Medical Informatics, Software
Abstract

Purpose: To develop and test a method to noninvasively assess the functional lung microstructure. Materials and Methods: The Multiple exchange time Xenon polarization Transfer Contrast technique (MXTC) encodes xenon gas-exchange contrast at multiple delay times permitting two lung-function parameters to be derived: (i) MXTC-F, the long exchange-time depolarization value, which is proportional to the tissue to alveolar-volume ratio and (ii) MXTC-S, the square root of the xenon exchange-time constant, which characterizes thickness and composition of alveolar septa. Three healthy volunteers, one asthmatic, and two chronic obstructive pulmonary disease (COPD) (GOLD stage I and II) subjects were imaged with MXTC MRI. In a subset of subjects, hyperpolarized xenon-129 ADC MRI and CT imaging were also performed. Results: The MXTC-S parameter was found to be elevated in subjects with lung disease (P-value = 0.018). In the MXTC-F parameter map it was feasible to identify regional loss of functional tissue in a COPD patient. MXTC-F maps showed excellent regional correlation with CT and ADC (P ≥ 0.90) in one COPD subject. Conclusion: The functional tissue-density parameter MXTC-F showed regional agreement with other imaging techniques. The newly developed parameter MXTC-S, which characterizes the functional thickness of alveolar septa, has potential as a novel biomarker for regional parenchymal inflammation or thickening. J. Magn. Reson. Imaging 2011;33:1052–1062. © 2011 Wiley-Liss, Inc.

Published
2011

6. Parity violation in neutron–proton capture—The NPDGamma experiment

Author

Michael Gericke, W. C. Chen, Gregory S. Mitchell, A. Salas-Bacci, R. Carlini, Ricardo Alarcon, Timothy Chupp, Stuart J. Freedman, H. Nann, S. Balascuta, J. Mei, E. I. Sharapov, R. C. Gillis, R. Mahurin, M. B. Leuschner, S. I. Penttilä, Yasuhiro Masuda, Thomas R. Gentile, V.W. Yuan, Bernhard Lauss, D. Ramsay, B. Losowki, Gordon L. Jones, S. Covrig, Geoffrey Greene, L. Barron, Takashi Ino, S. Santra, Suguru Muto, C. Crawford, W. M. Snow, F. W. Hersman, S. A. Page, T. B. Smith, J. D. Bowman, M. Sharma, P. N. Seo, W. S. Wilburn, and M. Dabaghyan

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Asymmetry, Nuclear physics, Neutron capture, Neutron source, Spallation, Neutron, Nuclear Experiment, Nucleon, Instrumentation, Spallation Neutron Source, media_common
Abstract

The NPDGamma collaboration has recently completed the first phase of a measurement to determine the size of the weak nucleon–nucleon interaction from cold neutron capture on a liquid hydrogen target. In the framework of the nearly 30 year old DDH model [B. Desplanques, J.F. Donoghue, B.R. Holstein, Annals of Physics 124 (1980) 449], the measured process is explained in terms of the weak pion–nucleon coupling, while the framework of modern effective field theory parameterizes the measured process in terms of the S 1 3 - P 1 3 , long range transition (essentially the Danilov parameter ρ t ) [S.L. Zhu et al., Nuclear Physics A 748 (2005) 435; C.-P. Liu, Phys. Rev. C 75 (2007) 065501]. The couplings in terms of either model are directly proportional to the parity violating up-down asymmetry in the angular distribution of gamma rays with respect to the neutron spin direction in the reaction n ⇒ + p → d + γ . The asymmetry has a predicted size of 5 × 10 - 8 and the aim of the NPDGamma collaboration is to measure it to 20%. The first phase of the measurement was completed at the Los Alamos National Laboratory Neutron Science Center Spallation Source with a preliminary result of ( - 1.1 ± 2.1 stat . ± 0.2 sys . ) × 10 - 7 . Here, we report on the measurements and the results obtained so far. The experiment is currently being installed at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, for the remainder of its run time.

Published
2009

7. Moments of the spin structure functions g1p and g1d for 0.05<Q2<3.0 GeV2

Author

R. A. Schumacher, G. V. O'Rielly, C. D. Keith, Cynthia Marie Hadjidakis, Z. W. Zhao, Chaden Djalali, D. G. Jenkins, Michael Dugger, S. Tkachenko, H. O. Funsten, A. I. Ostrovidov, A. C S Lima, S. Bültmann, L. Morand, M. R. Niroula, T. A. Forest, D. G. Ireland, G. Asryan, Volker D. Burkert, A. S. Biselli, J. Pierce, Elton Smith, M. J. Amaryan, M. MacCormick, O. P. Dzyubak, R. A. Niyazov, I. Hleiqawi, S. L. Careccia, Larry Weinstein, Avraham Klein, E. Golovatch, H. G. Juengst, K. Moriya, Daniel S. Carman, J. Kuhn, Philip L. Cole, S. McAleer, H. Hakobyan, S. Anefalos Pereira, P. D. Rubin, L. Blaszczyk, P. Corvisiero, Y. G. Sharabian, A. Fradi, L. Cheng, G. Audit, A.V. Stavinsky, C. E. Hyde-Wright, F. Sabatié, Nikolay Shvedunov, D. Heddle, P. Stoler, Friedrich Klein, J. P. Cummings, R. De Vita, N. Markov, V. Sapunenko, C. Salgado, Dinko Pocanic, L. Elouadrhiri, N. Kalantarians, S. Stepanyan, K. S. Egiyan, R. C. Minehart, C. A. Meyer, J. Ball, M. Taiuti, S. E. Kuhn, I. I. Strakovsky, M. Bektasoglu, M. Kossov, K. Mikhailov, K.H. Hicks, R. J. Feuerbach, G. V. Fedotov, M. Nozar, A. Deur, I. Popa, V. Crede, J. W. Price, Shifeng Chen, M. Anghinolfi, Laird Kramer, D. P. Watts, H. Egiyan, G. Gavalian, John A. Mueller, L. Casey, B. L. Berman, P. Mattione, B. B. Niczyporuk, G. Rosner, N. Benmouna, N. Pivnyuk, Kwangsoo Kim, J. T. Goetz, M. Mirazita, G. Riccardi, J. R. Calarco, R. A. Miskimen, B. A. Raue, B. McKinnon, W. J. Briscoe, L. M. Qin, R. G. Fersh, P. Eugenio, J. Langheinrich, C. Butuceanu, C. Hanretty, S. S. Stepanyan, E. Pasyuk, S. A. Philips, M. Ripani, G. Ricco, S. A. Morrow, C. Paterson, Y. Ilieva, Michael Vineyard, Victor Mokeev, M. Klusman, B. M. Preedom, D. Branford, P. Collins, B. Moreno, J. R. Johnstone, Lorenzo Zana, J. P. Santoro, Tsutomu Mibe, Gerald Feldman, J. M. Laget, L. Todor, D. Protopopescu, K. L. Giovanetti, S. V. Kuleshov, C. Marchand, S. Pozdniakov, M. Garçon, M. L. Seely, Ji Li, D. J. Tedeschi, G. E. Dodge, H. Y. Lu, J. Lachniet, I. Bedlinskiy, Marco A. Huertas, A. Tkabladze, M. D. Mestayer, E. L. Isupov, P. V. Degtyarenko, D. Rowntree, K. Livingston, Michael L. Williams, M. Holtrop, R. Suleiman, V. Kuznetsov, D. S. Dale, J. Zhang, S. Boiarinov, D. I. Sober, Gerard Gilfoyle, F. X. Girod, G. S. Mutchler, N. A. Baltzell, I. Niculescu, D. Sokhan, J. Salamanca, K. A. Griffioen, D. Lawrence, M. Guillo, N. Guler, R. De Masi, L. El Fassi, J. W C McNabb, Sylvain Bouchigny, H. Denizli, M. Guidal, M. Battaglieri, J. Hardie, S. Strauch, J. D. Kellie, Z. Krahn, R. Nasseripour, S. Barrow, P. Rossi, R. Dickson, N. Baillie, D. Doughty, V. Gyurjyan, R. Bradford, K. Lukashin, B. E. Stokes, G. S. Adams, H. Bagdasaryan, P. Nadel-Turonski, A. V. Skabelin, K. Joo, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, L. Guo, M. Ungaro, D. P. Weygand, E. Wolin, N. Hassall, M. Bellis, D. G. Crabb, J. Yun, D. Cords, P. Bosted, A. Yegneswaran, N. Dashyan, Y. Prok, Barry Ritchie, E. De Sanctis, H. S. Jo, S. Niccolai, R. Fatemi, A. V. Vlassov, P. Coltharp, R. W. Gothe, M. M. Ito, K. Y. Kim, M. Osipenko, K. Beard, L. C. Smith, E. Munevar, Kalvir S. Dhuga, B. S. Ishkhanov, O. Pogorelko, M. Khandaker, B. Zhao, F. W. Hersman, W. Kim, G. Niculescu, N. Gevorgyan, L. C. Dennis, B. E. Bonner, H. Avakian, D. Sharov, S. A. Dytman, W. K. Brooks, K. Park, V. P. Kubarovsky, J. Shaw, Michael Wood, K. Hafidi, and V. S. Serov

Subjects
Physics, Nuclear and High Energy Physics, Chiral perturbation theory, Heavy baryon chiral perturbation theory, Proton, 010308 nuclear & particles physics, Nuclear Theory, Hadron, 01 natural sciences, Baryon, Nuclear physics, Polarizability, 0103 physical sciences, Sum rule in quantum mechanics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The spin structure functions g 1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q 2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05 Q 2 5 GeV 2 and W 3 GeV . The first moments of g 1 for the proton and deuteron are presented – both have a negative slope at low Q 2 , as predicted by the extended Gerasimov–Drell–Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ 0 p is also reported. This quantity shows strong Q 2 dependence at low Q 2 . Our analysis of the Q 2 evolution of the first moment of g 1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ 0 p data and Chiral Perturbation calculations for γ 0 p , even at the lowest Q 2 .

Published
2009

8. Exclusive ρ0 electroproduction on the proton at CLAS

Author

J. Langheinrich, S. S. Stepanyan, E. Pasyuk, S. A. Philips, N. Dashyan, V. Sapunenko, G. Ricco, Alexei V. Klimenko, N. A. Baltzell, C. Salgado, Dinko Pocanic, Barry Ritchie, H. Denizli, A. V. Skabelin, K. A. Griffioen, B. Zhao, V. Gyurjyan, A. I. Ostrovidov, R. Fatemi, K. Park, S. E. Kuhn, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, H. G. Juengst, B. E. Stokes, G. S. Adams, G. V. Fedotov, V. P. Kubarovsky, J. Zhang, P. Eugenio, K. P. Adhikari, A. V. Vlassov, D. P. Weygand, G. E. Dodge, H. Y. Lu, M. J. Amaryan, G. V. O'Rielly, S. Niccolai, Z. W. Zhao, V. Mokeev, Y. Ilieva, Ji Li, D. G. Jenkins, C. Tur, Gerard Gilfoyle, Elton Smith, H. Hakobyan, A.V. Stavinsky, J. D. Kellie, M. Guidal, M. MacCormick, I. Hleiqawi, S. L. Careccia, R. De Vita, Friedrich Klein, Brian Raue, P. V. Degtyarenko, M. D. Mestayer, J. P. Didelez, R. Nasseripour, L. Todor, F. W. Hersman, P. Coltharp, E. L. Isupov, J. P. Cummings, W. Gohn, S. A. Morrow, S. McAleer, M. Anghinolfi, P. Nadel-Turonski, D. Sokhan, D. Protopopescu, D. J. Tedeschi, M. Holtrop, Michael L. Williams, P. Collins, K. L. Giovanetti, I. Niculescu, F. X. Girod, L. Blaszczyk, B. Carnahan, James Mueller, D. Lawrence, R. G. Fersch, R. A. Miskimen, B. McKinnon, S. Pozdniakov, M. Garçon, J. J. Melone, M. M. Ito, S. Boiarinov, Larry Weinstein, L. Zana, P. D. Rubin, R. De Masi, D. Keller, I. Bedlinskiy, B. M. Preedom, S. Anefalos Pereira, D. Schott, Y. G. Sharabian, R. A. Schumacher, P. L. Cole, M. Yurov, M. Taiuti, S. Mehrabyan, D. Branford, L. C. Smith, E. Munevar, G. S. Mutchler, B. S. Ishkhanov, Michael Wood, K. Hafidi, L. Graham, M. Kossov, M. E. McCracken, C. I O Gordon, J. M. Laget, V. Kuznetsov, J. Kuhn, E. Hourany, M. Khandaker, V. S. Serov, L. C. Dennis, B. E. Bonner, J. W. Price, Tsutomu Mibe, S. Bültmann, G. Audit, Shifeng Chen, C. Bookwalter, N. Gevorgyan, M. Osipenko, C. E. Hyde-Wright, J. P. Santoro, H. S. Jo, H. Avakian, L. Morand, I. Popa, D. Sharov, T. A. Forest, G. Riccardi, M. R. Niroula, E. De Sanctis, O. Pogorelko, S. Stepanyan, P. Mattione, C. Butuceanu, M. S. Saini, D. Doughty, J. Pierce, M. Ripani, B. L. Berman, Avraham Klein, L. M. Qin, M. Aghasyan, E. Wolin, Sergey Kuleshov, W. J. Briscoe, D. Heddle, J. T. Goetz, D. I. Sober, Kalvir S. Dhuga, M. Bektasoglu, S. A. Dytman, S. Dhamija, M. Nozar, E. Polli, M. Mirazita, C. Paterson, J. P. Ball, R. W. Gothe, Y. Prok, B. Moreno, W. Kim, J. Hardie, Hall Crannell, D. S. Carman, K. Livingston, G. Rosner, C. Marchand, G. Niculescu, D. S. Dale, N. Baillie, S. Park, Sylvain Bouchigny, J. Lachniet, A. Tkabladze, D. G. Crabb, R. Dickson, Michael Vineyard, D. G. Ireland, V. Crede, J. R. Calarco, P. Khetarpal, N. Guler, J. Salamanca, L. El Fassi, J. W C McNabb, S. Barrow, P. Rossi, L. Casey, H. Bagdasaryan, Volker D. Burkert, A. S. Biselli, B. B. Niczyporuk, N. Pivnyuk, P. Stoler, C. Hanretty, Laird Kramer, J. R. Johnstone, L. Guo, M. Ungaro, A. Fradi, K. Joo, D. Cords, N. Markov, A. Yegneswaran, K. Hicks, M. Battaglieri, R. Bradford, K. S. Egiyan, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, N. Hassall, M. Bellis, K. Mikhailov, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, S. Strauch, D. P. Watts, H. Egiyan, I. I. Strakovsky, A. Deur, W. K. Brooks, R. J. Feuerbach, Cynthia Marie Hadjidakis, M. Guillo, Chaden Djalali, Michael Dugger, L. Cheng, F. Sabatié, Nikolay Shvedunov, N. Kalantarians, G. Gavalian, S. Tkachenko, and N. Benmouna

Subjects
Quark, Physics, REPRESENTATION, Nuclear and High Energy Physics, Particle physics, Valence (chemistry), Proton, Hadron, Parton, VECTOR-MESON ELECTROPRODUCTION, Approx, PHOTONS, QCD, EVOLUTION, High Energy Physics - Experiment, Regge theory, Nuclear physics, Scattering amplitude, GENERALIZED PARTON DISTRIBUTIONS, VIRTUAL COMPTON-SCATTERING, VECTOR-MESON ELECTROPRODUCTION, LARGE MOMENTUM-TRANSFER, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, PHOTONS, QCD, REPRESENTATION, EVOLUTION, LARGE MOMENTUM-TRANSFER, GENERALIZED PARTON DISTRIBUTIONS, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, Nuclear Experiment, VIRTUAL COMPTON-SCATTERING
Abstract

The $e p\to e^\prime p \rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present., Comment: 29 pages, 29 figures

Published
2008

9. A large area polarized 3He neutron spin filter

Author

Thomas R. Gentile, R. C. Gillis, Timothy Chupp, Michael Gericke, J. D. Bowman, M. Mason, B. Lauss, Kevin P. Coulter, S. A. Page, M. Dabaghyan, W. S. Wilburn, T. B. Smith, F. W. Hersman, Gordon L. Jones, D. R. Rich, S. I. Penttilä, M. Kandes, M. Sharma, and W. C. Chen

Subjects
Physics, Nuclear and High Energy Physics, business.industry, Polarimetry, Neutron transmission, Spin filter, Neutron radiation, Polarizer, Polarization (waves), law.invention, Optics, law, Neutron, business, Instrumentation
Abstract

A large area polarized 3He neutron spin filter has been developed and tested in long-term operation. The polarizer cells have area 50 cm2 and larger allowing access to a large area neutron beam. Polarization of 3He up to 57 ± 1 % was measured by monitoring the neutron transmission through the 3He. The polarization was maintained over the course of several weeks, but the maximum attainable polarization declined over the course of a year-long run as the cell degraded, possibly due to long-term exposure to the neutron beam at high temperatures. The resulting neutron polarization and transmission are velocity dependent and are optimized for 5 A. Cell construction, polarizer design, performance, and polarimetry are described in this paper.

Published
2007

10. Measurement of the x- and Q2-dependence of the asymmetry A1 on the nucleon

Author

L. Elouadrhiri, R. A. Miskimen, M. Khandaker, B. McKinnon, G. Rosner, I. I. Strakovsky, R. W. Gothe, M. Bellis, D. Branford, P. Rossi, K. Y. Kim, A. Deur, S. V. Kuleshov, H. G. Juengst, K. S. Egiyan, P. V. Degtyarenko, P. Dragovitsch, M. Battaglieri, M. Nozar, D. J. Tedeschi, M. Taiuti, I. Bedlinskiy, L. Todor, J. P. Cummings, D. Doughty, F. X. Girod, S. Niccolai, D. Protopopescu, Laird Kramer, J. Hardie, V. Gyurjyan, R. De Masi, B. E. Stokes, F. Ronchetti, R. A. Schumacher, P. Corvisiero, V. P. Kubarovsky, G. S. Adams, D. Heddle, Brian Raue, M. Mirazita, G. Ricco, Dinko Pocanic, L. C. Smith, S. Tkachenko, R. Bradford, K. Lukashin, Y. G. Sharabian, O. Pogorelko, E. Wolin, S. McAleer, S. E. Kuhn, V. Sapunenko, B. S. Ishkhanov, Ji Li, Jean Laget, N. Benmouna, N. Pivnyuk, Rakhsha Nasseripour, B. Carnahan, L. C. Dennis, B. E. Bonner, M. Guillo, C. Tur, J. Napolitano, A. I. Ostrovidov, R. Fatemi, A. C S Lima, Gerard Gilfoyle, D. Cords, Marco A. Huertas, H. Avakian, E. S. Smith, K. Park, A. V. Vlassov, D. G. Ireland, M. R. Niroula, V. Batourine, B. Zhao, Y. Ilieva, E. L. Isupov, R. Suleiman, I. Hleiqawi, L. Guo, S. Bültmann, Volker D. Burkert, A. S. Biselli, H. S. Jo, E. Golovatch, Michael L. Williams, P. Bosted, S. L. Careccia, James Mueller, G. S. Mutchler, R. DeVita, M. Ripani, S. A. Morrow, Atilla Gonenc, M. MacCormick, C. Djalali, F. W. Hersman, T. A. Forest, M. Anghinolfi, P. D. Rubin, S. Stepanyan, A. Cazes, G. Gavalian, J. W. Price, S. Boiarinov, Maryam Moteabbed, B. M. Preedom, N. A. Baltzell, Sylvain Bouchigny, J. P. Ball, Y. Prok, K. L. Giovanetti, Michael Dugger, A. Yegneswaran, Shifeng Chen, K. V. Dharmawardane, J. Pierce, M. Kossov, Avraham Klein, Jens H. Kuhn, A. Stavinsky, Larry Weinstein, P. Ambrozewicz, E. Pasyuk, L. M. Qin, K. A. Griffioen, H. O. Funsten, P. Coltharp, U. Thoma, C. Keith, Lorenzo Zana, D. P. Weygand, S. A. Dytman, Hall Crannell, M. M. Ito, N. Baillie, J. T. Goetz, G. V. O'Rielly, C. Paterson, M. Klusman, K. Livingston, V. Crede, Z. W. Zhao, Frank Klein, D. G. Crabb, J. R. Calarco, S. Strauch, D. G. Jenkins, C. Salgado, J. D. Kellie, G. E. Dodge, S. Pozdniakov, N. Guler, J. W C McNabb, M. D. Mestayer, I. Niculescu, Nikolay Shvedunov, D. Lawrence, M. Guidal, D. I. Sober, S. S. Stepanyan, M. Osipenko, S. Barrow, F. Sabatié, Michael Vineyard, K. Beard, M. Garçon, B. Mecking, G. Riccardi, J. Shaw, C. Butuceanu, Michael Wood, W. K. Brooks, K. Hafidi, V. S. Serov, Victor Mokeev, M. Ungaro, K. Joo, J. Yun, J. P. Santoro, Roy Thompson, K. Kim, J. J. Manak, P. Eugenio, J. Zhang, H. Bagdasaryan, P. Collins, Daniel S. Carman, C. Hadjidakis, C. E. Hyde-Wright, M. Bektasoglu, J. Langheinrich, S. A. Philips, G. Niculescu, M. Holtrop, Hong Lu, P. L. Cole, P. Nadel-Turonski, Tsutomu Mibe, B. B. Niczyporuk, J. Lachniet, A. Tkabladze, D. Rowntree, R. S. Hakobyan, J. Donnelly, O. P. Dzyubak, R. A. Niyazov, R. J. Feuerbach, L. Morand, P. Stoler, E. De Sanctis, K. Hicks, W. Kim, Susan Taylor, K. Mikhailov, H. Egiyan, N. Markov, Barry Ritchie, G. Asryan, H. Denizli, A. V. Skabelin, R. C. Minehart, C. A. Meyer, G. V. Fedotov, and E. Polli

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Proton, 010308 nuclear & particles physics, media_common.quotation_subject, Momentum transfer, Quark model, Parton, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Invariant mass, 010306 general physics, Nucleon, media_common
Abstract

We report results for the virtual photon asymmetry A{sub 1} on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton ({sup 15}NH{sub 3}) and deuteron ({sup 15}ND{sub 3}) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present paper, we concentrate on our results for A{sub 1}(x,Q{sup 2}) and the related ratio g{sub 1}/F{sub 1}(x,Q{sup 2}) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q{sup 2} from 0.05 to 5.0 GeV{sup 2} and in final-state invariant mass W up to about 3 GeV. Our data show detailed structure in the resonance region, which leads to a strong Q{sup 2}--dependence of A{sub 1}(x,Q{sup 2}) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A{sub 1}(x,Q{sup 2}) is not strictly Q{sup 2}--independent. We add significantly to the world data set at high x, up to x = 0.6. Our data exceed the SU(6)-symmetric quark model expectation for both the proton and the deuteron whilemore » being consistent with a negative d-quark polarization up to our highest x. This data set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.« less

Published
2006

11. A system for open-access3He human lung imaging at very low field

Author

Samuel Patz, George P. Topulos, Ronald L. Walsworth, James P. Butler, Mirko I. Hrovat, Matthew S. Rosen, F. W. Hersman, Leo L. Tsai, J. Ng, I. Muradian, Iulian C. Ruset, and Ross W. Mair

Subjects
Radiological and Ultrasound Technology, Electromagnet, Field (physics), medicine.diagnostic_test, business.industry, Magnetic resonance imaging, Laser, Imaging phantom, law.invention, Human lung, Planar, Optics, medicine.anatomical_structure, law, medicine, Pulmonary blood flow, Radiology, Nuclear Medicine and imaging, Physical and Theoretical Chemistry, business, Spectroscopy, Biomedical engineering
Abstract

We describe a prototype system built to allow open-access very-low-field MRI of human lungs using laser-polarized (3)He gas. The system employs an open four-coil electromagnet with an operational B(0) field of 4 mT, and planar gradient coils that generate gradient fields up to 0.18 G/cm in the x and y direction and 0.41 G/cm in the z direction. This system was used to obtain (1)H and (3)He phantom images and supine and upright (3)He images of human lungs. We include discussion on challenges unique to imaging at 50 -200 kHz, including noise filtering and compensation for narrow-bandwidth coils.

Published
2006

12. Commissioning of the NPDGamma Detector Array: Counting Statistics in Current Mode Operation and Parity Violation in the Capture of Cold Neutrons on B4C and 27Al

Author

W. D. Ramsay, J. D. Bowman, Gregory S. Mitchell, M. Dabaghyan, S. Ishimoto, R. Mahurin, G. L. Greene, F. W. Hersman, Suguru Muto, Gordon L. Jones, H. Nann, E. I. Sharapov, W. S. Wilburn, S. A. Page, W. M. Snow, S. I. Penttilä, T. B. Smith, B. Lauss, Takashi Ino, P.-N. Seo, Kevin P. Coulter, M. B. Leuschner, Yasuhiro Masuda, B. Losowski, R. C. Gillis, Timothy Chupp, Michael Gericke, H. Zhu, R. Carlini, V. W. Yuan, S. Santra, T. R. Gentile, D. Desai, and Stuart J. Freedman

Subjects
Physics, detector, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Detector, General Engineering, Gamma ray, Neutron scattering, Article, Photodiode, law.invention, Nuclear physics, Neutron capture, Neutron flux, law, CsI, Statistics, current mode, Neutron, gamma, Nuclear Experiment, Spallation Neutron Source, neutron capture, parity violation
Abstract

The NPDGamma γ-ray detector has been built to measure, with high accuracy, the size of the small parity-violating asymmetry in the angular distribution of gamma rays from the capture of polarized cold neutrons by protons. The high cold neutron flux at the Los Alamos Neutron Scattering Center (LANSCE) spallation neutron source and control of systematic errors require the use of current mode detection with vacuum photodiodes and low-noise solid-state preamplifiers. We show that the detector array operates at counting statistics and that the asymmetries due to B4C and (27)Al are zero to with- in 2 × 10(-6) and 7 × 10(-7), respectively. Boron and aluminum are used throughout the experiment. The results presented here are preliminary.

Published
2005

13. Neutron decay correlations in the Nab experiment

Author

C. Hendrus, W. Farrar, J. Wexler, P. E. Mueller, R. Mammei, G. W. Dodson, A. Smith, J. R. Calarco, E. Frlež, Ricardo Alarcon, Christopher Crawford, Vladimir Gudkov, K. P. Rykaczewski, John Ramsey, S. A. Page, A. Salas-Bacci, M. Martinez, J. Fry, Geoffrey Greene, B. Plaster, J. Dubois, Susanne Mertens, J. D. Bowman, Takeyasu M. Ito, F. W. Hersman, L. Barrón Palos, Mark Makela, J. Mirabal-Martinez, Seppo Penttila, Juliette Mammei, Eric Stevens, Ferenc Glück, W. S. Wilburn, Nadia Fomin, Sky Sjue, Wenjiang Fan, J. Caylor, N. Birge, J. W. Martin, R. Picker, D. C. Radford, Aaron Sprow, Albert Young, S. Baeßler, Dinko Pocanic, T. Bode, T. Brunst, Michael Gericke, R. Whitehead, P. L. McGaughey, N. Macsai, B. A. Zeck, Timothy Chupp, Hui Li, E. M. Scott, Robert Grzywacz, V. Cianciolo, E. Smith, and Leah Broussard

Subjects
Physics, History, 010308 nuclear & particles physics, Nuclear Theory, 01 natural sciences, Measure (mathematics), Computer Science Applications, Education, Term (time), Nuclear physics, 0103 physical sciences, Beta particle, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Beta (finance)
Abstract

The Nab experiment will measure the correlation a between the momenta of the beta particle and antineutrino in neutron decay as well as the Fierz term b which distorts the beta spectrum.

Published
2017

14. New insights into lung diseases using hyperpolarized gas MRI

Author

L, Flors, T A, Altes, J P, Mugler, E E, de Lange, G W, Miller, J F, Mata, I C, Ruset, and F W, Hersman

Subjects
Lung Diseases, Xenon, Contrast Media, Humans, Helium, Magnetic Resonance Imaging
Abstract

Hyperpolarized (HP) gases are a new class of contrast agents that permit to obtain high temporal and spatial resolution magnetic resonance images (MRI) of the lung airspaces. HP gas MRI has become important research tool not only for morphological and functional evaluation of normal pulmonary physiology but also for regional quantification of pathologic changes occurring in several lung diseases. The purpose of this work is to provide an introduction to MRI using HP noble gases, describing both the basic principles of the technique and the new information about lung disease provided by clinical studies with this method. The applications of the technique in normal subjects, smoking related lung disease, asthma, and cystic fibrosis are reviewed.

Published
2014

15. Dynamics of the16O(e,e′p)Reaction at High Missing Energies

Author

C. Cavata, A. Soldi, A. J. Sarty, Y. Roblin, Paul Souder, T. Pussieux, K. Wijesooriya, Ronald Ransome, S. Malov, Shalev Gilad, E. Burtin, M. Liang, C. W. de Jager, K. A. Aniol, M. Holtrop, E. A.J.M. Offermann, Wolfgang Korsch, B. Doyle, G. Quéméner, P. Djawotho, T. Terasawa, Vincent Breton, A. Gasparian, A. V. Glamazdin, K. Joo, D. Rowntree, R. Holmes, C. R. Howell, D. M. Manley, J. R. Calarco, R. W. Lourie, O. Ravel, J. W. Watson, Justin I. McIntyre, J. Gao, E. J. Brash, W. U. Boeglin, B. D. Anderson, G. J. Lolos, M. B. Epstein, G. M. Urciuoli, J. A. Templon, W. Kahl, C. E. Hyde-Wright, S. Kerhoas, A. Serdarevic-Offermann, N. d'Hose, F. T. Baker, C. F. Perdrisat, S. Platchkov, Kazushige Maeda, A. Deur, G. M. Huber, T. Saito, J. Martino, L. Auerbach, Bogdan Wojtsekhowski, J. Domingo, J. Berthot, J. Y. Mougey, R. I. Pomatsalyuk, A. Saha, L. Bimbot, H. Ueno, Kevin Fissum, Z. Papandreou, T. P. Smith, Jian-Ping Chen, L. Todor, A. Leone, James J. Kelly, Seigo Kato, P.Y. Bertin, Nilanga Liyanage, G. Rutledge, Hiroaki Tsubota, Z. L. Zhou, Richard Wilson, Branislav Vlahovic, H. Fonvieille, Gordon D. Cates, Mauro Iodice, Larry Weinstein, G. Laveissière, R. Suleiman, E. Cisbani, William Bertozzi, S. Nanda, G. Kumbartzki, Jing Zhao, R. Madey, D. G. Zainea, Ronald Gilman, R. Roche, D. S. Dale, K. McCormick, R. Michaels, L. Cardman, P. E. Ulmer, V. Zeps, S. van Verst, Pete Markowitz, J. M. Finn, S. Jaminion, H. Breuer, J. Gomez, J.E. Ducret, M. Khandaker, R. A. Lindgren, J. J. LeRose, M. Khayat, H. Voskanyan, C. Jutier, D. Neyret, V. Gorbenko, Roberto Perrino, R. De Leo, F. W. Hersman, L. A. Ewell, B. Diederich, Laird Kramer, M. K. Jones, G. G. Petratos, J. S. McCarthy, T. P. Gorringe, Z. E. Meziani, P. M. Rutt, Leonid Levchuk, David L. Prout, F. Garibaldi, V. A. Punjabi, S. Frullani, P. Vernin, R. L.J. van der Meer, D. J. Margaziotis, C. C. Chang, K. S. Kumar, Pavel Sorokin, K. Kino, B. Frois, and Charles Glashausser

Subjects
Physics, Proton, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, 01 natural sciences, Nuclear physics, Cross section (geometry), Pion, 0103 physical sciences, Isobar, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25

Published
2001

16. Theep→e′pηReaction at and above theS11(1535)Baryon Resonance

Author

M. J. Amaryan, M. Taiuti, S. K. Matthews, J. Ficenec, Gyurjyan, W. Kim, A. Longhi, R. A. Schumacher, B. E. Bonner, L. Elouadrhiri, A. P. Freyberger, R. Magahiz, Robert E. Welsh, S. Dytman, S. Whisnant, B. M. Preedom, Federico Ronchetti, R. J. Feuerbach, K. L. Giovanetti, B. Asavapibhop, Michael Dugger, Shalev Gilad, De Sanctis E, A. V. Vlassov, G. Ricco, J. R. Kane, H. Avakian, Philip L. Cole, J. P. Cummings, G. S. Adams, Larry Weinstein, R. A. Miskimen, K. Joo, J. Shaw, R. W. Major, Moshe Gai, M. Kossov, W. J. Briscoe, D. Rowntree, D. Doughty, K. Beard, W. K. Brooks, Friedrich Klein, R. S. Hicks, Brian Raue, Kevin Fissum, Kalvir S. Dhuga, Barry Ritchie, A. Coleman, K. A. Griffioen, M. M. Ito, G. Riccardi, L. M. Qin, J. J. Manak, M. Mirazita, J. M. Laget, C. E. Hyde-Wright, J. W C McNabb, M. S. Ohandjanyan, D. Heddle, C. Salgado, H. R. Weller, Roy Thompson, Curtis Smith, D. P. Weygand, Herbert O. Funsten, S. A. Philips, Patrick Girard, Y. Kuang, H. Egiyan, M. Witkowski, Bernhard Mecking, Mestayer, A. J. Sarty, Jing Zhao, S. Stepanyan, De Vita R, D. G. Jenkins, C. Djalali, Z. L. Zhou, M. Lucas, Airton Deppman, D. I. Sober, A. Shafi, D. Hancock, Avraham Klein, Leskin Ga, M. Battaglieri, S. McAleer, William Bertozzi, E. Polli, E. Anciant, L. Farhi, G. E. Dodge, Daniel S. Carman, V. B. Gavrilov, O. Pogorelko, A. K. Opper, G. Audit, J. W. Price, M. Khandaker, E. Wolin, P. V. Degtyarenko, Y. Patois, Gerard Gilfoyle, Dinko Pocanic, L.C. Dennis, K. Loukachine, N. Pivnyuk, M. Bektasoglu, S. E. Kuhn, S. M. Shuvalov, D. Lawrence, M. Eckhause, J. Napolitano, M. Ripani, M. Guillo, Jochen Heisenberg, Y. V. Efremenko, Volker D. Burkert, M. Sanzone, J. Connelly, Donal Day, M. Sargsyan, G. A. Peterson, M. Guidal, A. V. Skabelin, J. Yun, D. Cords, A. Yegneswaran, A. S. Biselli, Elton Smith, S. Barrow, M. Holtrop, Thomas E. Smith, G. S. Mutchler, M. Anghinolfi, Hall Crannell, D. G. Crabb, James Mueller, S. Taylor, P. D. Rubin, G. Capitani, F. Roudot, D. J. Tedeschi, Y. G. Sharabian, M. Spraker, Sapunenko, R. C. Minehart, M. Klusman, Nicola Bianchi, S. Boiarinov, C. A. Meyer, J. S. McCarthy, B. Carnahan, Thierry Auger, A. R. Reolon, Michael Vineyard, C. Marchand, P. Rossi, P. Dragovitsch, F. W. Hersman, R. A. Demirchyan, T. Y. Tung, J. Hardie, K. Y. Kim, Muccifora, R. A. Niyazov, John T. O'Brien, P. Corvisiero, K. S. Egiyan, Calarco, P. Stoler, and K. Hicks

Subjects
Baryon, Physics, Nuclear physics, Particle physics, Photon, Amplitude, Angular distribution, Meson, Momentum transfer, General Physics and Astronomy, Resonance, Invariant (physics), Nuclear Experiment
Abstract

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

Published
2001

17. Transverse AsymmetryAT′from the Quasielastic3He→(e→,e′)Process and the Neutron Magnetic Form Factor

Author

J. Yeh, B. W. Filippone, William Bertozzi, Wolfgang Korsch, K. McIlhany, K. McCormick, M. Schnee, K. Kramer, L. Todor, T. Pavlin, R. I. Pomatsalyuk, L. Cardman, Jacek Golak, Nilanga Liyanage, F. W. Hersman, Branislav Vlahovic, R. Suleiman, A. Deur, Steffen Strauch, R. D. McKeown, J. O. Hansen, D. J. Margaziotis, J. Gomez, Bogdan Wojtsekhowski, Jian-Ping Chen, T. Averett, Charles Glashausser, de Jager Cw, Y. Roblin, D. Pripstein, W. Xu, J. S. Jensen, M. Sutter, I. K. Kominis, M. Liang, C. Crawford, Hiroyuki Kamada, Dipanwita Dutta, W. Glöckle, A. V. Glamazdin, Z. Chai, M. Viviani, Sebastien Incerti, C. F. Williamson, Gordon D. Cates, E. Lakuriqi, F. Xiong, B. Humensky, E. W. Hughes, Henryk Witała, G. G. Petratos, R. Michaels, B. D. Anderson, E. Pace, J. W. Watson, D. S. Dale, Jones Ce, Z. E. Meziani, B. Tipton, Ronald Ransome, G. S. Corrado, L. Auberbach, J. J. LeRose, A. Kievsky, V. Gorbenko, T. Black, Xin Jiang, R. Holmes, R. Kahl, D. W. Higinbotham, G. Salme, S. Churchwell, P. A. Zolnierczuk, J. M. Finn, G. Kumbartzki, C. R. Howell, J. R. Calarco, E. Chudakov, P. Djawotho, Karl Slifer, Haiyan Gao, Paul Souder, T. Shin, M. Rvachev, J. W. Martin, Seonho Choi, S. Malov, Ronald Gilman, M. K. Jones, A. Saha, G. W. Miller, M. Kuss, and David L. Prout

Subjects
Nuclear physics, Physics, Transverse plane, Quasielastic scattering, Experimental uncertainty analysis, media_common.quotation_subject, Magnetic form factor, General Physics and Astronomy, Neutron, Asymmetry, Polarized target, media_common
Abstract

We have measured the transverse asymmetry A_T′ in ^3He(e,e′) quasielastic scattering in Hall A at Jefferson Laboratory with high precision for Q^2 values from 0.1 to 0.6 (GeV/c)^2. The neutron magnetic form factor GMn was extracted based on Faddeev calculations for Q^2 = 0.1 and 0.2 (GeV/c)^2 with an experimental uncertainty of less than 2%.

Published
2000

18. Dynamical Relativistic Effects in Quasielastic1p-Shell Proton Knockout fromO16

Author

C. E. Hyde-Wright, D. J. Margaziotis, J. Martino, Nilanga Liyanage, C. R. Howell, K. Kino, M. Liang, Richard Wilson, J. R. Calarco, G. Quéméner, T. P. Smith, A. V. Glamazdin, Kazushige Maeda, Branislav Vlahovic, R. Suleiman, E. Cisbani, G. M. Urciuoli, K. Joo, S. Frullani, R. W. Lourie, R. Roche, S. Platchkov, D. Rowntree, Paul Souder, Y. Roblin, T. Terasawa, Vincent Breton, Bogdan Wojtsekhowski, W. Kahl, P. Vernin, T. Pussieux, J. M. Finn, J. Gao, J. Gomez, C. F. Perdrisat, B. Frois, Jian-Ping Chen, K. Wijesooriya, W. Korsh, O. Ravel, Hiroaki Tsubota, Ronald Ransome, Seigo Kato, R. L.J. van der Meer, S. Malov, E. Burtin, J. A. Templon, S. Kerhoas, J. W. Watson, M. Holtrop, B. Doyle, S. van Verst, R. Holmes, Z. Papandreou, R. A. Lindgren, J. J. LeRose, H. Voskanyan, C. Jutier, P. M. Rutt, A. Gasparian, G. Rutledge, F. T. Baker, G. M. Huber, David L. Prout, V. Gorbenko, M. Khayat, Charles Glashausser, B. D. Anderson, G. J. Lolos, M. B. Epstein, Mauro Iodice, L. Auerbach, A. Saha, H. Ueno, L. Todor, A. Leone, J. Berthot, Larry Weinstein, William Bertozzi, D. S. Dale, L. Cardman, S. Jaminion, Pete Markowitz, L. Bimbot, G. G. Petratos, Z. E. Meziani, M. Khandaker, V. Zeps, W. U. Boeglin, Leonid Levchuk, Roberto Perrino, R. De Leo, D. Neyret, V. A. Punjabi, B. Diederich, D. G. Zainea, C. C. Chang, K. S. Kumar, T. Saito, Pavel Sorokin, H. Fonvieille, G. Kumbartzki, J. Y. Mougey, F. Garibaldi, T. P. Gorringe, P. E. Ulmer, Z. L. Zhou, G. Laveissière, J. S. McCarthy, P. Djawotho, P.Y. Bertin, J.E. Ducret, Ronald Gilman, K. McCormick, M. K. Jones, A. Serdarevic-Offermann, A. Deur, H. Breuer, F. W. Hersman, L. A. Ewell, James J. Kelly, R. I. Pomatsalyuk, S. Nanda, Shalev Gilad, D. M. Manley, C. W. de Jager, K. A. Aniol, E. A.J.M. Offermann, J. Domingo, K. A. Griffioen, C. Cavata, A. Soldi, A. J. Sarty, Gordon D. Cates, Laird Kramer, R. Madey, E. J. Brash, Kevin Fissum, Jing Zhao, R. Michaels, Justin I. McIntyre, and N. d'Hose

Subjects
Physics, Nuclear reaction, Proton, 010308 nuclear & particles physics, Hadron, General Physics and Astronomy, Elementary particle, 01 natural sciences, Omega, Baryon, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Relativistic quantum chemistry
Abstract

We have measured the cross section for quasielastic 1p -shell proton knockout in the {sup 16}O( e, e{sup '}p) reaction at {omega}=0.439 GeV and Q{sup 2}=0.8 (GeV/c){sup 2} for missing momentum P{sub miss}{

Published
2000

19. The time-of-flight system for CLAS

Author

Elton Smith, K. Loukachine, A. D. Hancock, C. Marchand, J. Distelbrink, L. C. Smith, W. Kim, T.Y. Tung, J. Ficenec, K. MacArthur, G. S. Mutchler, Andrew G. Weisenberger, D. Schutt, Bernhard Mecking, L. Elouadrhiri, Robert E. Welsh, D. A. Jenkins, T. Carstens, F. W. Hersman, M. Guidal, M. Holtrop, Susan Taylor, H. Egiyan, T. P. Smith, and M. Eckhause

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Cosmic ray, Particle accelerator, Particle identification, Particle detector, Linear particle accelerator, law.invention, Nuclear physics, Time of flight, law, Scintillation counter, Instrumentation
Abstract

The time-of-flight system for the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility is described. The system, covering an area of 206-square-meters, is composed of scintillation counters 5.08 cm thick, 15 and 22 cm wide, and lengths which vary from 32 cm at the most forward angle to 450 cm at larger angles. All of the components of the system have been designed to optimize the time resolution. Event timing, achieved by leading-edge discrimination with time-walk correction, has been measured with cosmic rays, a laser pulser, and known particle interactions. The intrinsic time resolution varies from about 80 ps for the short counters to 160 ps for the longer counters. Reconstruction of interacting particles during the first period of operation yields an average time resolution for electrons of 163 ps.

Published
1999

20. Measurement of the neutral weak form factors of the proton

Author

Justin I. McIntyre, B. Frois, D. Neyret, J. Jardillier, G. D. Cates, A. V. Glamazdin, M. B. Epstein, J. M. Finn, B. Humensky, R. Holmes, D. Lhuillier, J. Gao, F. Garibaldi, D. S. Armstrong, Min Suk Kim, P. Mastromarino, K. Wijesooriya, C. F. Perdrisat, Sebastien Incerti, C. Cavata, J. Thompson, R. Michaels, A. Gasparian, R. I. Pomatsalyuk, Arijit Saha, W. Kahl, J. R. Calarco, F. Marie, G. A. Rutledge, T. Pussieux, Andre Fleck, V. Gorbenko, M. B. Leuschner, G. M. Gerstner, Kevin Fissum, L. Todor, G. Quéméner, J.P. Jorda, P. M. Rutt, E. Chudakov, Paul Souder, J. LeRose, V. A. Punjabi, Bogdan Wojtsekhowski, Daijin Kim, J. S. Price, N. Falletto, R. Suleiman, K. Kramer, Z. E. Meziani, E. Burtin, M. Holtrop, J. P. Chen, R. W. Lourie, D. S. Dale, Stephanie Escoffier, J. Martino, Richard Madey, F. W. Hersman, C. W. de Jager, K. A. Aniol, K. S. Kumar, L. A. Ewell, P. E. Ulmer, A. Deur, G. W. Miller, C. Jutier, David L. Prout, P. Djawotho, Nilanga Liyanage, Marcus Spradlin, G. G. Petratos, Richard Wilson, Branislav Vlahovic, M. K. Jones, D. J. Margaziotis, J. Gomez, M. Kuss, Ronald Gilman, K. McCormick, M. Baylac, and Olfred Hansen

Subjects
Quantum chromodynamics, Elastic scattering, Physics, Strange quark, Particle physics, Proton, Degree (graph theory), Electric form factor, FOS: Physical sciences, General Physics and Astronomy, Standard Model, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Sensitivity (control systems), Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G_E^s. The result, A=-14.5 +- 2.2 ppm, is consistent with the electroweak Standard Model and no additional contributions from strange quarks. In particular, the measurement implies G_E^s + 0.39G_M^s = 0.023 +- 0.034 (stat) +- 0.022 (syst) +- 0.026 (delta G_E^n), where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor., 10 pages, 4 figures, submitted to Phys. Rev. Lett

Published
1999

21. Low-Field MRI of Laser Polarized Noble Gas

Author

Ronald L. Walsworth, C. H. Tseng, D. P. Hinton, David G. Cory, Richard E. Stoner, F. W. Hersman, V. R. Pomeroy, G. P. Wong, D. Hoffmann, and Ross W. Mair

Subjects
Magnetic Resonance Spectroscopy, Materials science, Electromagnetics, General Physics and Astronomy, chemistry.chemical_element, Helium, law.invention, Diffusion, Optics, Nuclear magnetic resonance, law, medicine, medicine.diagnostic_test, Phantoms, Imaging, business.industry, Lasers, Noble gas, Magnetic resonance imaging, Equipment Design, Low field mri, Laser, Magnetic Resonance Imaging, chemistry, Lung disease, business, Porous medium, Electromagnetic Phenomena
Abstract

NMR images of laser polarized 3He gas were obtained at 21 G using a simple, homebuilt instrument. At such low fields magnetic resonance imaging (MRI) of thermally polarized samples (e.g., water) is not practical. Low-field noble gas MRI has novel scientific, engineering, and medical applications. Examples include portable systems for diagnosis of lung disease, as well as imaging of voids in porous media and within metallic systems.

Published
1998

22. The 12C(e, e′p) and 12C(e, e′pp) reactions in the Δ-resonance region

Author

Leon Kester, J.R. Calarco, T. P. Smith, L.J. de Bever, M.W. Kelder, Marc Vanderhaeghen, E. Jans, J. J. M. Steijger, J. Konijn, W.H.A. Hesselink, M. Kruijer, N. Kalantar-Nayestanaki, A. Pellegrino, Carlotta Giusti, Albert Zondervan, P.J. Countryman, Jan Ryckebusch, J.L. Visschers, F. W. Hersman, Franco Davide Pacati, Th.S. Bauer, J.H. Mitchell, M. Leuschner, and Other Research IHEF (IoP, FNWI)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Meson, Proton, Nuclear Theory, Resonance (particle physics), Coincidence, Nuclear physics, Pion, Correlation function, Atomic physics, Nuclear Experiment, Electron scattering
Abstract

Coincidence cross sections for the 12 C(e, e′pp) and 12 C(e, e′p) reactions have been measured in the Δ-resonance region. The 12 C(e, e′pp) reaction has been measured at three different angular settings of the proton detectors to investigate the angular correlation between the emitted protons. The data, which have a low statistical accuracy, are compared with a calculation based on the direct-knockout mechanism, which includes one- and two-body currents. NN-correlations are accounted for via a correlation function, Δ-excitation via a two-body current and final-state interactions of the emitted protons via an optical potential. The 12 C(e, e′p) data, taken at large proton-emission angles, cover the region of high missing-energy values (145–275 MeV). The data are compared to results of a calculation taking into account meson exchange, intermediate Δ-excitation and pion production. This comparison shows that there is ample evidence for processes leading to multi-nucleon knockout.

Published
1995

23. Short-Range Nucleon-Nucleon Correlations Investigated with the ReactionC12(e,e′pp)

Author

M.W. Kelder, E. Jans, J. H. Mitchell, J. Konijn, J. R. Calarco, Franco Davide Pacati, J. J. M. Steijger, D. DeAngelis, W.H.A. Hesselink, Carlotta Giusti, Jan Visschers, Z. Papandreou, Th. S. Bauer, Leon Kester, W. Kim, Nasser Kalantar-Nayestanaki, Antonio Pellegrino, F. W. Hersman, and Albert Zondervan

Subjects
Physics, Baryon, Nuclear reaction, Particle physics, Proton, Hadron, General Physics and Astronomy, Elementary particle, Atomic physics, Nucleon, Omega, Lepton
Abstract

The reaction $^{12}C({e,e}^{\ensuremath{'}}\mathrm{pp})$ has been studied at an energy transfer $\ensuremath{\omega}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}212\phantom{\rule{0ex}{0ex}}\mathrm{MeV}$ and a three-momentum transfer $|\mathit{q}|\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}70\phantom{\rule{0ex}{0ex}}\mathrm{MeV}/c$. The measured missing-energy spectrum shows a signature for knockout of proton pairs from $(1p{)}^{2}$, $(1p,1s)$, and $(1s{)}^{2}$ states. A comparison of the data with a calculation, in which different processes leading to two-nucleon knockout are accounted for, shows that the measured cross section for the knockout of a $(1p{)}^{2}$ pair can largely be attributed to short-range nucleon-nucleon correlations.

Published
1995

24. Neutron Beta Decay Studies with Nab

Author

L. P. Alonzi, T. V. Vianciolo, Robert Grzywacz, K. P. Rykaczewski, Vladimir Gudkov, A. Salas-Bacci, S. Balascuta, S. McGovern, D. Harrison, L. Barrón-Palos, Christopher Crawford, M. Bychkov, A. R. Young, F. Glück, Seppo Penttila, W. S. Wilburn, F. W. Hersman, P. L. McGaughey, S. A. Page, Daniel Wagner, J. W. Martin, Takeyasu M. Ito, S. Baeßler, Ricardo Alarcon, Geoffrey Greene, J. R. Calarco, E. Frlež, Mark Makela, Michael Gericke, J. D. Bowman, J. Byrne, Dinko Pocanic, Timothy Chupp, and Z. Tompkins

Subjects
Coupling constant, Physics, Nuclear physics, Spectrometer, FOS: Physical sciences, Neutron, Nuclear Experiment (nucl-ex), Nuclear Experiment, Beta decay, Standard Model
Abstract

Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer., Submitted to Proceedings of the Conference CIPANP12, St.Petersburg, Florida, May 2012

Published
2012

25. Measurement of parity-violatingγ-ray asymmetry in the capture of polarized cold neutrons on protons

Author

R. D. Carlini, Gordon L. Jones, S. Balascuta, Suguru Muto, Bernhard Lauss, T. R. Gentile, Nadia Fomin, W. M. Snow, S. Covrig, Timothy Chupp, R. Mahurin, S. A. Page, C. Blessinger, M. Sharma, T. B. Smith, Christopher Crawford, A. Salas-Bacci, Gregory S. Mitchell, J. D. Bowman, H. Nann, M. Dabaghyan, Ricardo Alarcon, Swadeshmukul Santra, L. Barrón-Palos, E. I. Sharapov, F. W. Hersman, R. C. Gillis, W. C. Chen, Seppo Penttila, Takashi Ino, M. B. Leuschner, W. R. Lozowski, Yasuhiro Masuda, J. Mei, Geoffrey Greene, W. D. Ramsay, Michael Gericke, V. W. Yuan, P.‐N. Seo, Stuart J. Freedman, and W. S. Wilburn

Subjects
Baryon, Nuclear reaction, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle decay, Particle physics, Hadron, Elementary particle, Fermion, Weak interaction, Nuclear Experiment, Nucleon
Abstract

The NPDGamma collaboration reports results from the first phase of a measurement of the parity violating up-down asymmetry ${A}_{\ensuremath{\gamma}}$ with respect to the neutron spin direction of $\ensuremath{\gamma}$ rays emitted in the reaction $\mathrm{nP\vec}+p\ensuremath{\rightarrow}d+\ensuremath{\gamma}$ using the capture of polarized cold neutrons on the protons in a liquid parahydrogen target. One expects parity-odd effects in the hadronic weak interaction between nucleons to be induced by the weak interaction between quarks. ${A}_{\ensuremath{\gamma}}$ in $\mathrm{nP\vec}+p\ensuremath{\rightarrow}d+\ensuremath{\gamma}$ is dominated by a $\ensuremath{\Delta}I=1$, ${}^{3}{S}_{1}$-${}^{3}{P}_{1}$ parity-odd transition amplitude in the n-p system. The first phase of the measurement was completed at the Los Alamos Neutron Science Center spallation source (LANSCE), with the result ${A}_{\ensuremath{\gamma}}=[\ensuremath{-}1.2\ifmmode\pm\else\textpm\fi{}2.1 (\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2 (\mathrm{sys}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. We also report the first measurement of an upper limit for the parity-allowed left-right asymmetry in this reaction, with the result ${A}_{\ensuremath{\gamma},\mathrm{LR}}=[\ensuremath{-}1.8\ifmmode\pm\else\textpm\fi{}1.9 (\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2 (\mathrm{sys}.)]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$. In this paper we give a detailed report on the theoretical background, experimental setup, measurements, extraction of parity-odd and parity-allowed asymmetries, analysis of potential systematic effects, and LANSCE results. The asymmetry has an estimated size of $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ and the aim of the NPDGamma collaboration is to measure it to $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$. The second phase of the measurement will be performed at the Spallation Neutron Source at Oak Ridge National Laboratory.

Published
2011

26. Analysis of sparsely distributed data: an application of the extended maximum-likelihood method

Author

F. W. Hersman, T. P. Smith, and Albert Zondervan

Subjects
Physics, Nuclear and High Energy Physics, Half-normal distribution, Exponential distribution, Likelihood-ratio test, Noncentral chi-squared distribution, Probability distribution, Likelihood function, Instrumentation, Distribution fitting, Algorithm, Scaled inverse chi-squared distribution
Abstract

Experimental measurements of quantities depending on several degrees of freedom are challenging to conventional fitting techniques. To address this problem we have developed and implemented a technique for fitting distribution functions to low-statistics data using the Poisson probability distribution function. We present a derivation of the likelihood function, which parallels χ 2 , and discuss its properties. Finally, we apply this technique to the extraction of a cross section from a recent 12 C(e, e′pp) triple-coincidence experiment. From a data set dominated by random-coincidences containing only a few hundred events, we were able to determine the number of true triple-coincidence events and its experimental uncertainty.

Published
1993

27. Ground-state magnetization density ofY89

Author

E. E. Saperstein, R. A. Miskimen, A. P. Platonov, J. R. Calarco, Jochen Heisenberg, G. A. Peterson, R. S. Hicks, F. W. Hersman, W. Kim, S. A. Fayans, J. P. Connelly, J. E. Wise, R.P. Singhal, and Tom Milliman

Subjects
Physics, Elastic scattering, Nuclear reaction, Nuclear and High Energy Physics, Magnetization, Scattering, Elastic electron, Atomic physics, Ground state, Polarization (waves), Fermi Gamma-ray Space Telescope
Abstract

Elastic electron scattering cross sections have been measured for [sup 89]Y at 180[degree] for 0.72[lt][ital q][lt]2.67 fm[sup [minus]1]. The [ital M]1 form factor has been extracted and a Fourier-Bessel analysis performed to obtain the ground-state magnetization density. Calculations including effects of core polarization have been performed within the framework of the finite Fermi system theory. These show a weakening of the strong repulsion in the spin-isospin channel and are in overall agreement with the data.

Published
1993

28. Neutron transition densities fromSr88(p,p’) atEp=200 MeV

Author

J. Calarco, W.P. Jones, C. Olmer, G.T. Emery, A.D. Bacher, J. P. Connelly, F. W. Hersman, Tom Milliman, M.L. Whiten, M. A. Grimm, B. S. Flanders, James J. Kelly, V. Penumetcha, F. T. Baker, Jochen Heisenberg, and Alan Scott

Subjects
Nuclear reaction, Baryon, Physics, Nuclear and High Energy Physics, Proton, Hadron, Neutron, Elementary particle, Atomic physics, Inelastic scattering, Nucleon
Abstract

New cross section and analyzing power data for [sup 88]Sr([ital p],[ital p][prime]) at [ital E][sub [ital p]]=200 MeV are reported and analyzed together with earlier cross section data. Neutron transition densities for low-lying normal-parity excitations were extracted using an empirical density-dependent effective interaction and an expansion of the radial density which permits analysis of uncertainties due to penetrability, distortion, incompleteness, statistics, and normalization. The densities were compared with shell-model calculations using effective operators based upon a density-dependent Hartree-Fock approximation. Good agreement between theory and experiment is obtained for the 2[sub 1][sup +], 3[sub 1][sup [minus]], and 5[sub 1][sup [minus]] states, but the experimental neutron densities for the 2[sub 2][sup +] and 7[sub 1][sup [minus]] states are considerably stronger than expected. Both proton and neutron transition densities for the 2[sub 2][sup +] state have strong interior lobes, but the theory fails to reproduce the accompanying surface lobes.

Published
1993

29. The reactions in the dip region

Author

Z. Papandreou, Albert Zondervan, Th. S. Bauer, J. Konijn, J. J. M. Steijger, Antonio Pellegrino, M.W. Kelder, E. Jans, W.H.A. Hesselink, M. Kruijer, J.M. Mitchell, W. Kim, Jan Visschers, J. R. Calarco, F. W. Hersman, Nasser Kalantar-Nayestanaki, Leon Kester, and P. C. Countryman

Subjects
Physics, Nuclear and High Energy Physics, Electron spectrometer, Proton, Energy transfer, Nuclear Theory, Detector, Momentum transfer, Angular correlation, Position (vector), Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Conjugate
Abstract

The reactions 12 C (e,e′pp) and 12 C (e,e′p) have been studied at an energy transfer ω = 210 MeV and a momentum transfer ‖q‖ = 267 MeV/c. The angular correlation between two emitted protons has been measured keeping the position of the electron spectrometer and one proton detector fixed, while the position of the other detector was varied around the conjugate angle. A clear signature for the emission of two correlated protons has been observed.

Published
1993

30. A System for Open-Access He Human Lung Imaging at Very Low Field

Author

I C, Ruset, L L, Tsai, R W, Mair, S, Patz, M I, Hrovat, M S, Rosen, I, Muradian, J, Ng, G P, Topulos, J P, Butler, R L, Walsworth, and F W, Hersman

Subjects
Article
Abstract

We describe a prototype system built to allow open-access very-low-field MRI of human lungs using laser-polarized (3)He gas. The system employs an open four-coil electromagnet with an operational B(0) field of 4 mT, and planar gradient coils that generate gradient fields up to 0.18 G/cm in the x and y direction and 0.41 G/cm in the z direction. This system was used to obtain (1)H and (3)He phantom images and supine and upright (3)He images of human lungs. We include discussion on challenges unique to imaging at 50 -200 kHz, including noise filtering and compensation for narrow-bandwidth coils.

Published
2010

31. Ground-state charge distribution and transition charge densities of the low-lying states inSr86

Author

Costas N. Papanicolas, Tom Milliman, W. Kim, J. P. Connelly, A. P. Platonov, S. A. Fayans, Jochen Heisenberg, F. W. Hersman, and J. E. Wise

Subjects
Elastic scattering, Physics, Nuclear and High Energy Physics, Scattering, Excited state, Momentum transfer, Charge density, Charge (physics), Atomic physics, Inelastic scattering, Ground state
Abstract

Differential cross sections for electron scattering from $^{86}\mathrm{Sr}$ have been measured for excited states below 3.5 MeV over a range of effective momentum transfer of 0.4 to 2.8 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$. The elastic scattering data have been analyzed to reconstruct the ground-state charge distribution. The inelastic scattering data have been analyzed to extract transition charge densities. Interpretation of the underlying nuclear structure is given in the framework of a self-consistent finite Fermi system theory.

Published
1992

32. Isospin character of the transition to the 0.803-MeV state inPb206fromπ±scattering at 180 MeV

Author

M. Leuschner, Steven J. Greene, Christopher Morris, D. J. Horen, M. Holtrop, S. J. Seestrom, M. A. Plum, J. R. Calarco, Robert W. Garnett, F. W. Hersman, Mohini W. Rawool-Sullivan, and J. D. Zumbro

Subjects
Elastic scattering, Nuclear reaction, Physics, Nuclear and High Energy Physics, Scattering, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Isospin, Isoscalar, Bound state, Quasiparticle, Inelastic scattering, Atomic physics
Abstract

Elastic and inelastic {pi}{sup {plus minus}} scattering by {sup 206}Pb has been studied to measure the isospin character of transitions to bound states. The data have been interpreted using both distorted wave impulse approximation and optical model potentials. The data for the collective states at 2.647 MeV (3{sup {minus}}) and 4.111 MeV (2{sup +}) are well reproduced with {delta}{sub {ital l}}{sup +}={delta}{sub {ital l}}{sup {minus}}={delta}{sub {ital l}}{sup {ital p}}, i.e., assuming that these transitions are isoscalar. For the 0.803-MeV, 2{sup +} level we deduce {ital M}{sub {ital n}}/{ital M}{sub {ital p}}=2.6{plus minus}0.3 which is in excellent agreement with a value obtained from inelastic heavy-ion scattering.

Published
1992

33. High resolution electron scattering from high spin states inPb208

Author

Tom Milliman, D. J. DeAngelis, Jochen Heisenberg, W. Kim, Costas N. Papanicolas, J. P. Connelly, J. E. Wise, M. Leuschner, and F. W. Hersman

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Spin states, Scattering, Momentum transfer, Atomic physics, Inelastic scattering, Spin (physics), Electron scattering, Energy (signal processing)
Abstract

Inelastic electron scattering cross sections have been measured from high spin transitions in {sup 208}Pb. Measurements were made over a range of momentum transfer of 1.1 to 2.9 fm{sup {minus}1} with energy resolution between 14 and 22 keV. In addition to the previously measured 14{sup {minus}}, 12{sup {minus}}, and 12{sup +} levels, electron scattering cross sections have been measured on {ital M}11, {ital M}10, {ital M}9, {ital E}9, and {ital E}7 transitions. High spin states are quenched from the predicted Woods-Saxon single particle amplitudes by 22% to 67%. Evidence is presented for the fragmentation of the 7.06 MeV 12{sup {minus}} transition strength. Results are interpreted in terms of the independent particle model.

Published
1992

34. Transition densities of collective excitations inSn118

Author

W. Kim, Jochen Heisenberg, J. P. Connelly, V.Y. Ponomarev, A. P. Platonov, F. W. Hersman, E. E. Saperstein, M. Leuschner, J.E. Wise, and S. A. Fayans

Subjects
Physics, Elastic scattering, Nuclear and High Energy Physics, Phonon, Scattering, Momentum transfer, Quasiparticle, Charge (physics), Atomic physics, Inelastic scattering, Electron scattering
Abstract

Electron scattering cross sections have been measured for the elastic and the first 2{sup +},3{sup {minus}} and low-lying 4{sup +} excitations in {sup 118}Sn. Forward angle data were taken for momentum transfers in the range 1.24{lt}{ital q}{lt}2.74 fm{sup {minus}1} allowing the extraction of transition charge densities in a Fourier-Bessel analysis. Comparisons are made with microscopic calculations performed in the framework of the self-consistent finite Fermi system theory and quasiparticle phonon approach.

Published
1992

35. Interplay between single-particle and collective degrees of freedom in the excitation of the low-lying states inCe140

Author

L. S. Cardman, F. W. Hersman, V. Meot, B. Frois, B. L. Miller, A. P. Platonov, J. P. Connelly, S. A. Fayans, Jochen Heisenberg, W. Kim, V. Yu. Ponomarev, J. E. Wise, J. R. Calarco, Tom Milliman, P. E. Mueller, Costas N. Papanicolas, and D. Goutte

Subjects
Physics, Nuclear and High Energy Physics, Phonon, Scattering, Momentum transfer, Degrees of freedom (physics and chemistry), Quasiparticle, Atomic physics, Inelastic scattering, Electron scattering, Excitation
Abstract

Differential cross sections for electron scattering from {sup 140}Ce have been measured for excitation energies less than 3.3 MeV over a range of effective momentum transfer of 0.4 to 3.1 fm{sup {minus}1}. The data have been analyzed to extract transition charge densities. These densities are interpreted in terms of a quasiparticle-phonon model and self-consistent finite Fermi system theory to disentangle the collective and noncollective modes of excitation.

Published
1992

36. Precise Measurement of the Neutron Magnetic Form FactorGMnin the Few-GeV2Region

Author

R. J. Feuerbach, J. P. Cummings, L. C. Smith, E. Munevar, R. De Masi, D. Keller, M. Kossov, B. S. Ishkhanov, I. Popa, K. S. Egiyan, G. Ricco, K. Mikhailov, L. Cheng, M. Khandaker, M. Garçon, J. Shaw, Michael Wood, P. Nadel-Turonski, Nikolay Shvedunov, M. R. Niroula, K. Hafidi, R. Nasseripour, S. McAleer, Friedrich Klein, B. P. Quinn, Brian Raue, V. S. Serov, L. Casey, F. X. Girod, Susan Taylor, Marco A. Huertas, M. Lowry, V. Sapunenko, D. P. Watts, L. C. Dennis, B. E. Bonner, Hartmuth Arenhövel, Dinko Pocanic, H. Egiyan, R. G. Fersch, H. Avakian, D. Doughty, B. B. Niczyporuk, G. S. Adams, S. Park, D. Sharov, N. Kalantarians, P. L. Cole, Sylvain Bouchigny, Sabine Jeschonnek, R. C. Minehart, Kei Moriya, D. Heddle, P. Rossi, J. Lachniet, H. G. Juengst, C. A. Meyer, N. Pivnyuk, K. Joo, W. J. Briscoe, B. L. Berman, A. Tkabladze, G. V. Fedotov, E. Pasyuk, D. Rowntree, A. Coleman, L. M. Qin, M. Y. Gabrielyan, S. E. Kuhn, S. A. Dytman, V. Crede, Y. Ilieva, J. R. Calarco, T. Mineeva, J. W. Price, M. J. Amaryan, C. Paterson, S. Strauch, M. MacCormick, A.V. Stavinsky, M. Klusman, I. Hleiqawi, V. P. Kubarovsky, K. P. Adhikari, S. L. Careccia, A. Empl, L. El Fassi, O. Pogorelko, B. Moreno, D. P. Weygand, J. Salamanca, R. Suleiman, M. E. McCracken, Elton Smith, K. L. Giovanetti, B. Asavapibhop, G. V. O'Rielly, Tsutomu Mibe, Larry Weinstein, Z. W. Zhao, J. W C McNabb, D. J. Tedeschi, D. Protopopescu, D. G. Jenkins, Barry Ritchie, M. Anghinolfi, James Mueller, S. Malace, S. A. Morrow, P. Rubin, I. Bedlinskiy, G. S. Mutchler, Konstantin Stopani, S. Pozdniakov, V. Gyurjyan, M. M. Ito, C. Djalali, Y. G. Sharabian, G. Rosner, T. Kageya, K. Livingston, D. S. Dale, X. Wei, R. Dickson, V. Kuznetsov, C. E. Hyde-Wright, H. Denizli, N. Guler, N. A. Baltzell, P. Mattione, K. A. Griffioen, M. S. Saini, A. V. Skabelin, P. Dragovitsch, J. Zhang, S. Barrow, E. De Sanctis, S. Niccolai, J. T. Goetz, E. Polli, H. Bagdasaryan, R. A. Miskimen, J. D. Kellie, B. McKinnon, Sergey Kuleshov, M. Bektasoglu, J. Hardie, M. Nozar, W. Kim, Laird Kramer, G. Niculescu, D. I. Sober, D. Branford, M. Guidal, R. A. Schumacher, H. Hakobyan, M. Mirazita, P. Khetarpal, C. Hanretty, J. M. Laget, M. Holtrop, Victor Mokeev, L. Graham, J. R. Johnstone, N. Gevorgyan, L. Guo, M. Ungaro, M. Osipenko, F. Sabatié, A. Daniel, K. Beard, Kalvir S. Dhuga, S. Bültmann, A. I. Ostrovidov, J. Yun, D. Cords, V. Batourine, T. A. Forest, A. Yegneswaran, A. C S Lima, A. Sandorfi, K. Park, R. Fatemi, S. Stepanyan, A. V. Vlassov, D. G. Ireland, Volker D. Burkert, A. S. Biselli, J. Pierce, Avraham Klein, B. Zhao, J. Langheinrich, R. De Vita, A. Fradi, S. S. Stepanyan, S. A. Philips, William Brooks, N. Markov, P. Konczykowski, B. E. Stokes, J. J. Manak, S. Anefalos Pereira, G. E. Dodge, H. Y. Lu, N. Dashyan, Maryam Moteabbed, P. V. Degtyarenko, K. V. Dharmawardane, I. Niculescu, D. Lawrence, D. Schott, F. W. Hersman, M. Battaglieri, N. Baillie, P. Stoler, K. Hicks, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, R. Bradford, B. A. Mecking, K. Lukashin, E. Wolin, Gerard Gilfoyle, M. Guillo, D. Sokhan, W. Gohn, N. Hassall, M. Bellis, E. Golovatch, J. P. Ball, J. Hu, Y. Prok, D. S. Carman, S. Dhamija, M. D. Mestayer, L. Elouadrhiri, I. I. Strakovsky, E. L. Isupov, R. W. Gothe, G. Gavalian, S. Tkachenko, A. Deur, Michael L. Williams, J. Kuhn, N. Benmouna, J. P. Santoro, Andrei Afanasev, M. Ripani, D. G. Crabb, K. Y. Kim, Roy Thompson, Cynthia Marie Hadjidakis, S. Boiarinov, Michael Dugger, B. M. Preedom, Douglas Higinbotham, M. Yurov, Lorenzo Zana, H. S. Jo, C. Bookwalter, C. Salgado, Kwangsoo Kim, G. Riccardi, P. Eugenio, A. Starostin, M. Taiuti, Michael Vineyard, and P. Collins

Subjects
Physics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, General Physics and Astronomy, Scintillator, 7. Clean energy, 01 natural sciences, Nuclear physics, Dipole, Deuterium, 0103 physical sciences, Magnetic form factor, Neutron detection, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Electron scattering
Abstract

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.

Published
2009

37. Search for the Photoexcitation of Exotic Mesons in theπ+π+π−System

Author

M. Nozar, C. Salgado, D. P. Weygand, L. Guo, G. Adams, Ji Li, P. Eugenio, M. J. Amaryan, M. Anghinolfi, G. Asryan, H. Avakian, H. Bagdasaryan, N. Baillie, J. P. Ball, N. A. Baltzell, S. Barrow, M. Battaglieri, I. Bedlinskiy, M. Bektasoglu, M. Bellis, N. Benmouna, B. L. Berman, A. S. Biselli, L. Blaszczyk, B. E. Bonner, S. Bouchigny, S. Boiarinov, R. Bradford, D. Branford, W. J. Briscoe, W. K. Brooks, S. Bültmann, V. D. Burkert, C. Butuceanu, J. R. Calarco, S. L. Careccia, D. S. Carman, B. Carnahan, L. Casey, A. Cazes, S. Chen, L. Cheng, P. L. Cole, P. Collins, P. Coltharp, D. Cords, P. Corvisiero, D. Crabb, H. Crannell, V. Crede, J. P. Cummings, D. Dale, N. Dashyan, R. De Masi, R. De Vita, E. De Sanctis, P. V. Degtyarenko, H. Denizli, L. Dennis, A. Deur, K. V. Dharmawardane, K. S. Dhuga, R. Dickson, C. Djalali, G. E. Dodge, D. Doughty, M. Dugger, S. Dytman, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. El Fassi, L. Elouadrhiri, R. Fatemi, G. Fedotov, R. J. Feuerbach, T. A. Forest, A. Fradi, H. Funsten, M. Garçon, G. Gavalian, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, R. W. Gothe, K. A. Griffioen, M. Guidal, M. Guillo, N. Guler, V. Gyurjyan, C. Hadjidakis, K. Hafidi, H. Hakobyan, C. Hanretty, J. Hardie, N. Hassall, D. Heddle, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, C. E. Hyde-Wright, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, M. M. Ito, D. Jenkins, H. S. Jo, J. R. Johnstone, K. Joo, H. G. Juengst, N. Kalantarians, J. D. Kellie, M. Khandaker, W. Kim, A. Klein, F. J. Klein, M. Kossov, Z. Krahn, L. H. Kramer, V. Kubarovsky, J. Kuhn, S. E. Kuhn, S. V. Kuleshov, V. Kuznetsov, J. Lachniet, J. M. Laget, J. Langheinrich, D. Lawrence, K. Livingston, H. Y. Lu, M. MacCormick, N. Markov, P. Mattione, S. McAleer, B. McKinnon, J. W. C. McNabb, B. A. Mecking, S. Mehrabyan, M. D. Mestayer, C. A. Meyer, T. Mibe, K. Mikhailov, M. Mirazita, R. Miskimen, V. Mokeev, B. Moreno, K. Moriya, S. A. Morrow, M. Moteabbed, J. Mueller, E. Munevar, G. S. Mutchler, P. Nadel-Turonski, R. Nasseripour, S. Niccolai, G. Niculescu, I. Niculescu, B. B. Niczyporuk, M. R. Niroula, R. A. Niyazov, G. V. O’Rielly, M. Osipenko, A. I. Ostrovidov, K. Park, E. Pasyuk, C. Paterson, S. Anefalos Pereira, S. A. Philips, J. Pierce, N. Pivnyuk, D. Pocanic, O. Pogorelko, E. Polli, I. Popa, S. Pozdniakov, B. M. Preedom, J. W. Price, Y. Prok, D. Protopopescu, L. M. Qin, B. A. Raue, G. Riccardi, G. Ricco, M. Ripani, B. G. Ritchie, F. Ronchetti, G. Rosner, P. Rossi, P. D. Rubin, F. Sabatié, J. Salamanca, J. P. Santoro, V. Sapunenko, R. A. Schumacher, V. S. Serov, Y. G. Sharabian, D. Sharov, N. V. Shvedunov, A. V. Skabelin, E. S. Smith, L. C. Smith, D. I. Sober, D. Sokhan, A. Stavinsky, S. S. Stepanyan, S. Stepanyan, B. E. Stokes, P. Stoler, I. I. Strakovsky, S. Strauch, M. Taiuti, D. J. Tedeschi, U. Thoma, A. Tkabladze, S. Tkachenko, L. Todor, M. Ungaro, M. F. Vineyard, A. V. Vlassov, D. P. Watts, L. B. Weinstein, M. Williams, E. Wolin, M. H. Wood, A. Yegneswaran, L. Zana, J. Zhang, B. Zhao, and Z. W. Zhao

Subjects
Quantum chromodynamics, Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Nuclear physics, Excited state, 0103 physical sciences, Isobar, Production (computer science), 010306 general physics, Spin-½
Abstract

A search for exotic mesons in the $$\pi^{+}\pi^{+}\pi^{-}$$ system photoproduced by the charge exchange reaction $$\gamma p\to \pi^{+}\pi^{+}\pi^{-}(n)$$ was carried out by the CLAS collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A Partial Wave Analysis (PWA) was performed on a sample of 83,000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the photoproduction of an exotic $$J^{PC} = 1^{-+}$$ resonant state in the 1 to 2 GeV mass range. Our PWA analysis, based on the isobar model, shows production of the $$a_{2}(1320)$$ and the $$\pi_{2}(1670)$$ mesons, but no evidence for the $$a_{1}(1260)$$, nor the $$\pi_{1}(1600)$$ exotic state at the expected levels. An upper limit of 13.5 nb is determined for the exotic $$\pi_1(1600)$$ cross section, less than 2% of the $a_2(1320)

Published
2009

38. Measurement of Directf0(980)Photoproduction on the Proton

Author

S. Park, Sylvain Bouchigny, V. Crede, J. R. Calarco, E. Wolin, C. E. Hyde, R. A. Schumacher, V. Sapunenko, Dinko Pocanic, P. Nadel-Turonski, L. Casey, V. Mokeev, D. Lawrence, J. P. Cummings, H. G. Juengst, B. E. Stokes, Cynthia Marie Hadjidakis, J. P. Ball, D. S. Carman, A. Fradi, A. V. Vlassov, P. Konczykowski, M. J. Amaryan, S. Dhamija, Michael Dugger, K. Livingston, D. S. Dale, T. Lee, Maryam Moteabbed, M. Kossov, S. E. Kuhn, L. Graham, Ashot Gasparian, B. B. Niczyporuk, C. I O Gordon, M. MacCormick, R. W. Gothe, Z. W. Zhao, R. Dickson, N. Gevorgyan, T. Kageya, H. Avakian, I. Hleiqawi, K. V. Dharmawardane, A.V. Stavinsky, J. Donnelly, G. Asryan, N. Pivnyuk, D. G. Crabb, J. Kuhn, M. E. McCracken, R. De Vita, S. Strauch, E. Clinton, S. Bültmann, S. L. Careccia, D. G. Jenkins, O. P. Dzyubak, D. P. Watts, H. Egiyan, Gerard Gilfoyle, G. Ricco, Lorenzo Zana, J. P. Santoro, C. Tur, L. Gan, Tsutomu Mibe, W. Gohn, T. A. Forest, D. J. Tedeschi, N. Markov, D. Sokhan, D. Sharov, W. Kim, S. Anefalos Pereira, S. Stepanyan, G. Niculescu, M. Yurov, J. Goett, R. A. Miskimen, I. Bedlinskiy, B. McKinnon, M. Y. Gabrielyan, J. Pierce, K. L. Giovanetti, F. X. Girod, Sergey Kuleshov, Avraham Klein, Shifeng Chen, N. Guler, E. Golovatch, Friedrich Klein, Larry Weinstein, N. A. Baltzell, G. E. Dodge, P. Khetarpal, K. A. Stopani, Brian Raue, D. Keller, H. Y. Lu, M. Nozar, D. Branford, J. Salamanca, H. S. Jo, C. Bookwalter, E. De Sanctis, L. Lesniak, G. Riccardi, J. M. Laget, V. V. Mochalov, P. Mattione, K. A. Griffioen, M. Aghasyan, X. Wei, V. Kuznetsov, M. S. Saini, P. V. Degtyarenko, A. I. Ostrovidov, D. I. Sober, A. Sandorfi, K. Park, P. Eugenio, Adam P. Szczepaniak, V. Batourine, C. Hanretty, A. Starostin, M. Guidal, N. Dashyan, M. Taiuti, W. J. Briscoe, E. Pasyuk, H. Hakobyan, S. A. Morrow, G. Rosner, J. T. Goetz, M. Mirazita, C. Djalali, Paolo Rossi, M. Khandaker, L. Bibrzycki, I. Niculescu, J. Lachniet, A. Tkabladze, Y. Ilieva, J. W. Price, M. Holtrop, R. A. Niyazov, Elton Smith, D. G. Ireland, A. Daniel, A. Teymurazyan, I. I. Strakovsky, G. Gavalian, N. Hassall, M. Bellis, P. Ambrozewicz, P. Collins, B. Zhao, R. De Masi, S. Tkachenko, D. Schott, M. Ripani, D. Doughty, P. Stoler, J. J. Melone, S. Niccolai, Z. Krahn, Volker D. Burkert, A. S. Biselli, M. Anghinolfi, C. Salgado, N. Benmouna, J. Langheinrich, S. S. Stepanyan, D. Heddle, J. D. Kellie, A. Deur, N. Baillie, T. Mineeva, S. Malace, Mark W. Paris, J. R. Johnstone, Hall Crannell, M. Osipenko, V. P. Kubarovsky, Y. G. Sharabian, Laird Kramer, L. Cheng, W. K. Brooks, J. Hardie, F. W. Hersman, R. S. Hakobyan, L. Guo, M. Ungaro, B. Moreno, O. Pogorelko, G. S. Mutchler, K. Hicks, Nikolay Shvedunov, D. Protopopescu, B. L. Berman, K. S. Egiyan, L. El Fassi, S. Pozdniakov, M. Garçon, Michael Wood, K. Mikhailov, K. Hafidi, V. S. Serov, M. Battaglieri, N. Kalantarians, R. Bradford, B. A. Mecking, R. Nasseripour, K. Joo, A. Yegneswaran, Michael Vineyard, V. Gyurjyan, J. Zhang, H. Bagdasaryan, L. Todor, R. G. Fersch, C. Paterson, Ji Li, P. L. Cole, M. D. Mestayer, E. L. Isupov, Michael L. Williams, M. M. Ito, S. Boiarinov, F. Sabatié, L. C. Smith, E. Munevar, B. S. Ishkhanov, M. R. Niroula, M. Lowry, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, G. V. Fedotov, K. P. Adhikari, D. P. Weygand, O. Glamazdin, Alexei V. Klimenko, Y. Prok, Barry Ritchie, and I. Nakagawa

Subjects
Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, General Physics and Astronomy, Resonance, 01 natural sciences, 7. Clean energy, Nuclear physics, Particle decay, Pion, 0103 physical sciences, 010306 general physics, Nucleon
Abstract

We report on the results of the first measurement of exclusive f{sub 0}(980) meson photoproduction on protons for E{sub {gamma}}=3.0-3.8 GeV and -t=0.4-1.0 GeV{sup 2}. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the {pi}{sup +}{pi}{sup -} channel by performing a partial wave analysis of the reaction {gamma}p{yields}p{pi}{sup +}{pi}{sup -}. Clear evidence of the f{sub 0}(980) meson was found in the interference between P and S waves at M{sub {pi}{sup +}}{sub {pi}{sup -}}{approx}1 GeV. The S-wave differential cross section integrated in the mass range of the f{sub 0}(980) was found to be a factor of about 50 smaller than the cross section for the {rho} meson. This is the first time the f{sub 0}(980) meson has been measured in a photoproduction experiment.

Published
2009

39. Electroproduction ofpπ+π−off protons at0.2<Q2<0.6GeV2and1.3<W<1.57GeV with the CLAS detector

Author

P. Stoler, N. A. Baltzell, V. Crede, K. Hicks, J. R. Calarco, K. A. Griffioen, K. S. Egiyan, J. D. Kellie, C. Paterson, H. Denizli, S. Strauch, M. Klusman, M. Guidal, J. W C McNabb, K. Livingston, Nikolay Shvedunov, G. S. Mutchler, R. Dickson, Shifeng Chen, M. Osipenko, M. Holtrop, G. E. Dodge, V. Gyurjyan, P. Eugenio, P. V. Degtyarenko, Laird Kramer, J. Donnelly, G. Asryan, C. E. Hyde, O. P. Dzyubak, M. Taiuti, Marco A. Huertas, G. Rosner, T. Mineeva, J. Zhang, N. Guler, F. X. Girod, J. Langheinrich, I. Niculescu, V. Batourine, B. Carnahan, R. A. Niyazov, E. De Sanctis, Hovhannes Baghdasaryan, Sylvain Bouchigny, L. C. Smith, J. T. Goetz, J. P. Cummings, D. Lawrence, A.V. Stavinsky, B. B. Niczyporuk, P. Corvisiero, L. Guo, P. Rossi, B. S. Ishkhanov, M. Ungaro, R. A. Miskimen, B. McKinnon, H. G. Juengst, Susan Taylor, E. Wolin, D. I. Sober, J. W. Price, Konstantin Stopani, D. J. Tedeschi, V. Sapunenko, N. Pivnyuk, K. Mikhailov, Y. Prok, D. Branford, Dinko Pocanic, M. Mirazita, H. Egiyan, E. Golovatch, William Brooks, J. M. Laget, L. Todor, S. E. Kuhn, R. Fatemi, J. P. Ball, I. Bedlinskiy, Sergey Kuleshov, Rakhsha Nasseripour, Hall Crannell, M. Bektasoglu, A. Yegneswaran, B. E. Stokes, D. Protopopescu, S. Pozdniakov, A. V. Vlassov, K. V. Dharmawardane, D. S. Carman, G. S. Adams, C. Tur, T. Lee, G. Ricco, K. Joo, J. Kuhn, D. G. Jenkins, A. I. Ostrovidov, Roy Thompson, G. V. O'Rielly, K. Park, R. De Vita, R. A. Schumacher, Elton Smith, R. J. Feuerbach, Victor Mokeev, J. Shaw, Y. Ilieva, S. A. Morrow, C. Djalali, G. Niculescu, M. Anghinolfi, Michael Wood, D. G. Ireland, D. G. Crabb, M. D. Mestayer, P. Coltharp, Friedrich Klein, James Mueller, N. Dashyan, S. Bültmann, T. A. Forest, Brian Raue, G. Gavalian, N. Hassall, M. Bellis, M. Guillo, S. Stepanyan, S. Niccolai, M. M. Ito, E. L. Isupov, Volker D. Burkert, J. Pierce, Avraham Klein, A. S. Biselli, P. D. Rubin, J. Hardie, J. Hu, P. Ambrozewicz, M. Battaglieri, V. S. Serov, L. C. Dennis, Michael L. Williams, B. E. Bonner, R. Bradford, B. A. Mecking, S. Tkachenko, N. Benmouna, F. Sabatié, Y. G. Sharabian, H. Avakian, Kwangsoo Kim, C. Butuceanu, M. Ripani, N. Markov, S. Boiarinov, D. Sharov, Cynthia Marie Hadjidakis, Michael Dugger, H. O. Funsten, E. Pasyuk, S. A. Dytman, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, A. Tkabladze, G. V. Fedotov, Michael Vineyard, D. P. Weygand, Alexei V. Klimenko, V. P. Kubarovsky, Barry Ritchie, O. Pogorelko, Lorenzo Zana, J. P. Santoro, H. S. Jo, D. Doughty, C. Salgado, M. E. McCracken, P. Nadel-Turonski, Tsutomu Mibe, M. Khandaker, N. Gevorgyan, Z. Krahn, J. Lachniet, N. Baillie, Gerard Gilfoyle, D. Rowntree, M. J. Amaryan, R. W. Gothe, I. Hleiqawi, K. Y. Kim, S. L. Careccia, P. L. Cole, K. L. Giovanetti, B. Asavapibhop, Larry Weinstein, F. W. Hersman, and W. Kim

Subjects
Baryon, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Meson, Hadron, Elementary particle, Invariant mass, Sensitivity (control systems), Nucleon
Abstract

This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep{yields}e{sup '}p{pi}{sup +}{pi}{sup -}. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2

Published
2009

40. Measurement of semi-inclusive pi+ electroproduction off the proton

Author

L. C. Smith, E. Munevar, M. H. Wood, Y. Ilieva, M. E. McCracken, P. Nadel-Turonski, E. Wolin, R. J. Feuerbach, B. S. Ishkhanov, G. E. Dodge, Tsutomu Mibe, P. V. Degtyarenko, J. P. Ball, Y. Prok, D. S. Carman, M. R. Niroula, Alexander Ilyichev, O. P. Dzyubak, I. I. Strakovsky, Paolo Rossi, K. S. Egiyan, P. L. Cole, Z. W. Zhao, J. Lachniet, A. Tkabladze, W. Kim, I. Niculescu, R. A. Niyazov, D. G. Crabb, R. S. Hakobyan, L. El Fassi, Elton Smith, A. Deur, G. Niculescu, R. De Masi, B. L. Berman, J. Kuhn, B. McKinnon, W. K. Brooks, G. P. Gilfoyle, K. Livingston, R. Fatemi, N. Markov, A. V. Vlassov, J. P. Cummings, M. Anghinolfi, G. Ricco, B. Zhao, D. J. Tedeschi, S. Niccolai, R. Dickson, Ji Li, Y. G. Sharabian, S. Strauch, D. P. Watts, H. Egiyan, L. M. Qin, C. Paterson, L. Zana, D. Branford, J. M. Laget, M. Khandaker, G. Riccardi, N. Hassall, M. Bellis, Cynthia Marie Hadjidakis, R. De Vita, A. I. Ostrovidov, K. A. Griffioen, N. Guler, F. W. Hersman, J. Hardie, C. Butuceanu, M. J. Amaryan, M. Kossov, Shifeng Chen, E. N. Golovach, Volker D. Burkert, A. S. Biselli, Michael Dugger, J. Langheinrich, H. O. Funsten, H. G. Juengst, Luca Trentadue, M. MacCormick, I. Hleiqawi, M. D. Mestayer, C. Djalali, H. Denizli, P. Eugenio, S. Dytman, A. V. Skabelin, S. L. Careccia, I. Popa, P. Coltharp, R. A. Schumacher, P. Mattione, M. Osipenko, S. Barrow, M. Taiuti, A.V. Stavinsky, S. Anefalos Pereira, P. D. Rubin, R. W. Gothe, Laird Kramer, E. L. Isupov, D. Lawrence, D. Sokhan, M. M. Ito, H. Hakobyan, A. Cazes, J. R. Calarco, C. I O Gordon, K. L. Giovanetti, S. Mehrabyan, Alexei V. Klimenko, J. T. Goetz, R. Miskimen, C. Hanretty, G. V. O'Rielly, E. Polli, Michael L. Williams, Larry Weinstein, M. Mirazita, Kalvir S. Dhuga, J. D. Kellie, P. Collins, Friedrich Klein, F. Sabatié, Nikolay Shvedunov, J. J. Melone, V. Sapunenko, Sylvain Bouchigny, S. Bültmann, L. Todor, Barry Ritchie, Dinko Pocanic, Victor Mokeev, Brian Raue, G. Asryan, E. De Sanctis, M. Battaglieri, I. Bedlinskiy, V. A. Drozdov, S. Stepanyan, S. E. Kuhn, N. A. Baltzell, D. Protopopescu, S. Pozdniakov, M. Garçon, M. F. Vineyard, J. Pierce, Avraham Klein, Z. Krahn, N. Dashyan, S. Boiarinov, U. Thoma, D. I. Sober, R. Bradford, N. Kalantarians, Latifa Elouadrhiri, V. Gyurjyan, G. S. Mutchler, D. G. Ireland, V. Crede, N. Baillie, B. B. Niczyporuk, R. C. Minehart, Kei Moriya, S. McAleer, N. Pivnyuk, B. E. Stokes, J. Napolitano, G. S. Adams, J. Zhang, B. M. Preedom, F. X. Girod, L. Blaszczyk, H. Bagdasaryan, J. P. Santoro, C. Tur, C. A. Meyer, L. Guo, M. Ungaro, G. Gavalian, J. Donnelly, S. Tkachenko, D. Heddle, J. Salamanca, N. Benmouna, G. V. Fedotov, M. Ripani, J. W C McNabb, D. Jenkins, R. Nasseripour, S. A. Morrow, K. Joo, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, A. Yegneswaran, Atilla Gonenc, P. Ambrozewicz, J. W. Price, M. Holtrop, D. P. Weygand, P. Corvisiero, H. S. Jo, Gerald Feldman, Federico A. Ceccopieri, C. Salgado, G. Rosner, M. Guillo, K. Mikhailov, M. Guidal, H. Y. Lu, C. E. Hyde-Wright, P. Stoler, Sergey Kuleshov, M. Bektasoglu, M. Nozar, K. Hicks, S. S. Stepanyan, S. A. Philips, J. Mueller, K. Hafidi, V. S. Serov, K. Park, V. P. Kubarovsky, O. Pogorelko, L. C. Dennis, B. E. Bonner, H. Avakian, W. J. Briscoe, E. Pasyuk, D. Doughty, 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), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and 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)

Subjects
Particle physics, Nuclear and High Energy Physics, Proton, DEEP-INELASTIC-SCATTERING, TARGET FRAGMENTATION REGION, TRANSVERSE-MOMENTUM, PARTON DISTRIBUTIONS, AZIMUTHAL ASYMMETRY, PION ELECTROPRODUCTION, CHARGED HADRONS, HARD PROCESSES, LEADING ORDER, CROSS-SECTION, TARGET FRAGMENTATION REGION, Hadron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Spectral line, Nuclear physics, Pion, Factorization, 0103 physical sciences, 010306 general physics, Nuclear Experiment, PION ELECTROPRODUCTION, Physics, DEEP-INELASTIC-SCATTERING, 010308 nuclear & particles physics, LEADING ORDER, TRANSVERSE-MOMENTUM, Azimuth, Diquark, CHARGED HADRONS, HARD PROCESSES, PARTON DISTRIBUTIONS, Cathode ray, AZIMUTHAL ASYMMETRY, High Energy Physics::Experiment, CROSS-SECTION
Abstract

Semi-inclusive {pi}{sup +} electroproduction on protons has been measured with the CLAS detector at Jefferson Lab. The measurement was performed on a liquid-hydrogen target using a 5.75 GeV electron beam. The complete five-fold differential cross sections were measured over a wide kinematic range including the complete range of azimuthal angles between hadronic and leptonic planes, {phi}, enabling us to separate the {phi}-dependent terms. Our measurements of the {phi}-independent term of the cross section at low Bjorken x were found to be in fairly good agreement with pQCD calculations. Indeed, the conventional current fragmentation calculation can account for almost all of the observed cross section, even at small {pi}{sup +} momentum. The measured center-of-momentum spectra are in qualitative agreement with high-energy data, which suggests a surprising numerical similarity between the spectator diquark fragmentation in the present reaction and the antiquark fragmentation measured in e{sup +}e{sup -} collisions. We have observed that the two {phi}-dependent terms of the cross section are small. Within our precision the cos2{phi} term is compatible with zero, except for the low-z region, and the measured cos{phi} term is much smaller in magnitude than the sum of the Cahn and Berger effects.

Published
2009

41. Properties of low-lying states inCe142via high resolution electron scattering

Author

J. E. Wise, Costas N. Papanicolas, W. Kim, J. R. Calarco, J. P. Connelly, F. W. Hersman, E. E. Saperstein, Tom Milliman, Jochen Heisenberg, V. Yu. Ponomarev, B. L. Miller, and A. P. Platonov

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Scattering, Momentum transfer, Charge density, Charge (physics), Inelastic scattering, Atomic physics, Electron scattering, Excitation
Abstract

Differential cross sections for inelastic scattering from $^{142}\mathrm{Ce}$ have been measured for excitation energies less than 3.3 MeV over a range of momentum transfer of 0.4 to 2.5 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$. The data have been analyzed to extract transition charge densities. These densities are interpreted in terms of a quasiparticle-phonon approach and finite Fermi system theory to disentangle the collective and noncollective modes of excitation.

Published
1991

42. Electroexcitation of negative-parity states inO18

Author

B. Pugh, B. L. Berman, D. J. Millener, John M. Finn, William Bertozzi, C. E. Hyde-Wright, D. M. Manley, M.V. Hynes, James J. Kelly, T. N. Buti, B. Murdock, Michael A. Kovash, F. W. Hersman, R. W. Lourie, C. P. Sargent, S. Kowalski, and B. E. Norum

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Scattering, Coulomb, Parity (physics), Atomic physics, Inelastic scattering, Wave function, Omega, Harmonic oscillator
Abstract

Form-factor measurements in the momentum-transfer range 0.6{le}{ital q}{le}2.7 fm{sup {minus}1} are presented for the 1{sup {minus}} levels in {sup 18}O at 4.46, 6.20, 7.62, and 8.04 MeV, the 3{sup {minus}} levels at 5.10, 6.40, and 8.29 MeV, and the 5{sup {minus}} levels at 7.86 and 8.13 MeV. These are the first measurements of the 5{sup {minus}} states by inelastic scattering and the first electron-scattering measurements of the higher 1{sup {minus}} and 3{sup {minus}} states. A Rosenbluth separation of the longitudinal and transverse form factors was performed by fitting the data with a phenomenological polynomial-times-Gaussian parametrization motivated by the form of theoretical form factors when harmonic-oscillator wave functions are used. Comparisons are made with structure models. The Coulomb form factors of several levels indicate the significance of small admixtures of 3{h bar}{omega} components in the negative-parity wave functions.

Published
1991

43. Electron scattering fromBe9

Author

William Bertozzi, M.V. Hynes, D. J. Millener, B. E. Norum, T. N. Buti, James J. Kelly, C. E. Hyde-Wright, B. L. Berman, S. Dixit, J. Glickman, R. W. Lourie, and F. W. Hersman

Subjects
Elastic scattering, Nuclear reaction, Physics, Nuclear and High Energy Physics, Scattering, Momentum transfer, Atomic physics, Inelastic scattering, Ground state, Isotopes of beryllium, Omega
Abstract

The structure of $^{9}\mathrm{Be}$ is investigated using electron scattering measurements at 90\ifmmode^\circ\else\textdegree\fi{} and 160\ifmmode^\circ\else\textdegree\fi{} for momentum transfers between about 1.0 and 2.5 ${\mathrm{fm}}^{\mathrm{\ensuremath{-}}1}$. In addition to the 3/${2}^{\mathrm{\ensuremath{-}}}$ ground state and the narrow 5/${2}^{\mathrm{\ensuremath{-}}}$ state at 2.43 MeV, detailed line-shape analysis was used to extract cross sections for broad states at 1.68, 3.05, 4.70, 6.38, 6.76, 11.28, and 13.79 MeV. The previously unknown state at 6.38 MeV was isolated from the known 6.76 MeV state in both (e,e') and (p,p') data using the dependence of peak position upon momentum transfer. On the basis of the form factor, the 6.38 MeV state replaces the 6.76 MeV state as the 7/${2}^{\mathrm{\ensuremath{-}}}$ member of the ground-state rotational band and the 6.76 MeV state is identified with the lowest 9/${2}^{+}$ state predicted by the shell model. The data for all states are compared with a shell-model calculation that uses the full 0\ensuremath{\Elzxh}\ensuremath{\omega} and 1\ensuremath{\Elzxh}\ensuremath{\omega} model spaces. Calculations are also presented for the narrow states between 14 and 18 MeV excitation.

Published
1991

44. Structure ofBe9from proton scattering at 180 MeV

Author

C. E. Hyde-Wright, J. M. Finn, T. N. Buti, James J. Kelly, B. E. Norum, B. L. Berman, D. J. Millener, A. D. Bacher, M.V. Hynes, D.W. Miller, M. A. Kovash, C. C. Foster, W.P. Jones, S. Dixit, William Bertozzi, F. W. Hersman, and G.T. Emery

Subjects
Physics, Nuclear reaction, Elastic scattering, Nuclear and High Energy Physics, Proton, Scattering, Momentum transfer, Atomic physics, Inelastic scattering, Born approximation, Resonance (particle physics)
Abstract

Cross section and analyzing power measurements for the scattering of 180 MeV protons are used to investigate the structure of $^{9}\mathrm{Be}$. Data were collected for 24 states below 21 MeV of excitation. Detailed line-shape analysis was used to isolate several broad states. Most notably, the dependence of apparent peak position upon momentum transfer was used to separate the strong resonance listed as 6.76 MeV in standard compilations into two contributions identified as the 7/${2}^{\mathrm{\ensuremath{-}}}$ member of the ground-state rotational band, located at 6.38 MeV, and the 9/${2}^{+}$ weak-coupling state, located at 6.76 MeV. Calculations of proton scattering were made using a density-dependent effective interaction in the local density approximation. The quadrupole contribution to elastic scattering was included in distorted wave Born approximation and found to have an important effect upon the analyzing power. For states dominated by a single multipolarity, neutron transition densities were fitted to (p,p') data and compared with the corresponding proton transition densities fitted to (e,e') data. We find that excitation of the rotational states and the 9/${2}^{+}$ state are essentially isoscalar. Shell model calculations were performed in the full 0\ensuremath{\Elzxh}\ensuremath{\omega} and 1\ensuremath{\Elzxh}\ensuremath{\omega} model spaces. Suggested assignments for most states are made by comparisons of shell model calculations with data for both (p,p') and (e,e'). Similar calculations for analog states observed with the $^{9}\mathrm{Be}$(p,n${)}^{9}$B reaction at 135 MeV support the proposed assignments. Finally, several relatively narrow states are observed between 18 and 21 MeV that are candidates for positive-parity states with T=3/2.

Published
1991

45. Electroexcitation of the Roper resonance for1.7<Q2<4.5GeV2ine→p→enπ+

Author

B. Zhao, F. W. Hersman, Marco Ripani, S. Dhamija, R. W. Gothe, K. Y. Kim, J. Kuhn, J. P. Santoro, E. De Sanctis, Latifa Elouadrhiri, B. M. Preedom, P. Eugenio, R. C. Minehart, Kei Moriya, D. I. Sober, M. Taiuti, G. Rosner, C. A. Meyer, M. Battaglieri, G. V. Fedotov, P. Collins, J. J. Melone, Lorenzo Zana, R. Bradford, K. Lukashin, J. Shaw, V. Batourine, D. P. Weygand, H. Hakobyan, Friedrich Klein, H. S. Jo, Michael Wood, K. Hafidi, Brian Raue, Gerald Feldman, Elton Smith, R. Fatemi, V. S. Serov, A. V. Vlassov, T. Lee, M. Anghinolfi, P. Coltharp, James Mueller, I. I. Strakovsky, N. A. Baltzell, R. De Vita, P. D. Rubin, A. Cazes, Maryam Moteabbed, C. Salgado, Bernhard Mecking, Y. G. Sharabian, A. Deur, K. A. Griffioen, K. S. Egiyan, K. V. Dharmawardane, Baile Zhang, Alexei V. Klimenko, S. Anefalos Pereira, Z. Krahn, W. K. Brooks, Shifeng Chen, J. D. Kellie, Y. Prok, N. Hassall, M. Bellis, J. Langheinrich, Barry Ritchie, N. Baillie, P. Mattione, M. S. Saini, L. C. Dennis, B. E. Bonner, S. S. Stepanyan, S. A. Philips, R. A. Miskimen, B. McKinnon, H. Avakian, J. T. Goetz, E. Polli, B. L. Berman, D. Sharov, M. Mirazita, D. Branford, K. Livingston, D. S. Dale, Ji Li, L. M. Qin, J. M. Laget, H. Denizli, N. Gevorgyan, C. Paterson, G. Gavalian, W. J. Briscoe, E. Pasyuk, S. Tkachenko, M. D. Mestayer, S. A. Dytman, J. Donnelly, G. Asryan, A. V. Skabelin, N. Benmouna, Gerard Gilfoyle, O. P. Dzyubak, R. A. Niyazov, E. L. Isupov, A. Fradi, D. Sokhan, M. Guillo, V. Crede, Michael L. Williams, W. Gohn, N. Markov, V. Sapunenko, Dinko Pocanic, J. R. Calarco, P. Corvisiero, E. Golovatch, S. Boiarinov, S. E. Kuhn, Charles Hyde, V. P. Kubarovsky, O. Pogorelko, C. Tur, M. J. Amaryan, M. MacCormick, I. Hleiqawi, R. Nasseripour, S. L. Careccia, S. McAleer, F. X. Girod, Laird Kramer, B. E. Stokes, G. S. Adams, J. P. Cummings, Cynthia Marie Hadjidakis, G. E. Dodge, H. Y. Lu, K. L. Giovanetti, L. Blaszczyk, P. V. Degtyarenko, M. Kossov, V. Gyurjyan, K. Joo, I. Popa, Sergey Kuleshov, M. Bektasoglu, Michael Dugger, D. Heddle, M. Nozar, P. Stoler, I. Niculescu, D. Lawrence, J. Zhang, R. De Masi, D. Schott, S. A. Morrow, C. Djalali, R. A. Schumacher, M. Guidal, Larry Weinstein, K. Hicks, M. Holtrop, L. Graham, H. Bagdasaryan, C. I O Gordon, P. Ambrozewicz, S. Bültmann, L. Morand, T. A. Forest, S. Stepanyan, J. Pierce, Avraham Klein, K. Mikhailov, L. Cheng, Nikolay Shvedunov, A. I. Ostrovidov, L. Casey, A. C S Lima, K. Park, N. Kalantarians, B. B. Niczyporuk, D. G. Ireland, Michael Vineyard, N. Pivnyuk, Giovanni Ricco, Atilla Gonenc, E. Wolin, Volker D. Burkert, A. S. Biselli, J. P. Ball, D. S. Carman, D. G. Crabb, J. Salamanca, J. W C McNabb, M. Yurov, J. W. Price, S. Mehrabyan, C. Bookwalter, G. Riccardi, H. Funsten, P. Nadel-Turonski, C. Butuceanu, Tsutomu Mibe, N. Dashyan, K. Hafnaoui, C. Hanretty, G. V. O'Rielly, J. R. Johnstone, Z. W. Zhao, D. Keller, Paolo Rossi, D. G. Jenkins, J. Lachniet, A. Tkabladze, S. Park, Sylvain Bouchigny, D. Rowntree, M. M. Ito, R. S. Hakobyan, L. El Fassi, M. Khandaker, H. G. Juengst, A.V. Stavinsky, D. J. Tedeschi, V. Mokeev, I. Bedlinskiy, L. C. Smith, E. Munevar, B. S. Ishkhanov, M. R. Niroula, V. Kuznetsov, S. Strauch, R. Suleiman, L. Guo, G. S. Mutchler, M. Ungaro, S. Niccolai, J. Hardie, D. Doughty, W. Kim, D. P. Watts, G. Niculescu, J. Yun, D. Cords, H. Egiyan, T. Takeuchi, A. Yegneswaran, M. Osipenko, F. Sabatié, Kalvir S. Dhuga, M. Y. Gabrielyan, R. Dickson, R. J. Feuerbach, N. Guler, Inna Aznauryan, P. L. Cole, S. Barrow, L. Todor, D. Protopopescu, S. Pozdniakov, M. Garçon, Y. Ilieva, and B. Moreno

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Roper resonance, Meson production, 010308 nuclear & particles physics, State (functional analysis), 01 natural sciences, Helicity, Baryon, 0103 physical sciences, Pi, Isobar, 010306 general physics, Ground state
Abstract

The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for $1.7l{Q}^{2}l4.5\phantom{\rule{0.3em}{0ex}}{\mathrm{GeV}}^{2}$ from recent high precision JLab-CLAS cross section and longitudinally polarized beam asymmetry data for ${\ensuremath{\pi}}^{+}$ electroproduction on protons at $W=1.15\ensuremath{-}1.69$ GeV. The analysis is made using two approaches, dispersion relations and a unitary isobar model, which give consistent ${Q}^{2}$ behavior of the helicity amplitudes for the ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}$N(1440)P${}_{11}$ transition. It is found that the transverse helicity amplitude ${A}_{1/2}$, which is large and negative at ${Q}^{2}=0$, becomes large and positive at ${Q}^{2}\ensuremath{\simeq}2\phantom{\rule{0.3em}{0ex}}{\mathrm{GeV}}^{2}$, and then drops slowly with ${Q}^{2}$. The longitudinal helicity amplitude ${S}_{1/2}$, which was previously found from CLAS $\stackrel{\ensuremath{\rightarrow}}{e}p\ensuremath{\rightarrow}\mathit{ep}{\ensuremath{\pi}}^{0},\mathit{en}{\ensuremath{\pi}}^{+}$ data to be large and positive at ${Q}^{2}=0.4,0.65\phantom{\rule{0.3em}{0ex}}{\mathrm{GeV}}^{2}$, drops with ${Q}^{2}$. Available model predictions for ${\ensuremath{\gamma}}^{*}p\ensuremath{\rightarrow}$N(1440)P${}_{11}$ allow us to conclude that these results provide strong evidence in favor of N(1440)P${}_{11}$ as a first radial excitation of the $3q$ ground state. The results of the present paper also confirm the conclusion of our previous analysis for ${Q}^{2}l1$ GeV${}^{2}$ that the presentation of N(1440)P${}_{11}$ as a q$^{3}\mathrm{G}$ hybrid state is ruled out.

Published
2008

46. Electroproduction ofϕ(1020)mesons at1.4⩽Q2⩽3.8GeV2measured with the CLAS spectrometer

Author

M. Guidal, R. Nasseripour, M. Holtrop, I. I. Strakovsky, R. J. Feuerbach, G. V. O'Rielly, Cynthia Marie Hadjidakis, B. Zhao, Z. W. Zhao, D. G. Jenkins, Alexei V. Klimenko, R. De Masi, A. Deur, Michael Dugger, H. O. Funsten, Michael Wood, K. Hafidi, N. Dashyan, B. E. Stokes, G. S. Adams, Barry Ritchie, P. L. Cole, B. M. Preedom, V. S. Serov, C. E. Hyde-Wright, S. McAleer, J. Langheinrich, S. S. Stepanyan, S. A. Philips, L. Blaszczyk, G. Ricco, J. Ball, F. W. Hersman, Sergey Kuleshov, Lorenzo Zana, J. P. Santoro, M. Bektasoglu, M. Nozar, M. Garçon, Elton Smith, M. Battaglieri, J. Salamanca, J. Lachniet, A. Tkabladze, Latifa Elouadrhiri, P. Coltharp, H. Hakobyan, F. Sabatié, H. S. Jo, K. Livingston, D. S. Dale, J. W C McNabb, J. R. Ficenec, N. A. Baltzell, V. Kuznetsov, R. Bradford, R. C. Minehart, Kei Moriya, C. A. Meyer, J. W. Price, M. M. Ito, S. Strauch, V. Mokeev, C. Salgado, L. Cheng, B. L. Berman, L. M. Qin, D. P. Watts, H. Egiyan, K. A. Griffioen, J. P. Cummings, V. Gyurjyan, G. V. Fedotov, S. A. Morrow, M. Anghinolfi, E. De Sanctis, V. P. Kubarovsky, D. Keller, Nikolay Shvedunov, Friedrich Klein, R. Dickson, James Mueller, C. Paterson, D. I. Sober, O. Pogorelko, C. Djalali, E. Munevar, D. P. Weygand, L. C. Smith, M. Kossov, L. C. Dennis, J. Zhang, B. E. Bonner, H. Avakian, Ji Li, M. Guillo, Brian Raue, S. Niccolai, I. Popa, S. Dhamija, N. Hassall, M. Bellis, H. Bagdasaryan, F. X. Girod, B. S. Ishkhanov, S. Park, R. Fatemi, N. Kalantarians, W. Gohn, A. V. Vlassov, J. R. Johnstone, D. Sharov, M. D. Mestayer, Y. G. Sharabian, Sylvain Bouchigny, J. Hardie, H. G. Juengst, J. Kuhn, L. El Fassi, C. Marchand, G. Audit, E. Wolin, H. Denizli, E. L. Isupov, R. De Vita, J. D. Kellie, L. Morand, Michael L. Williams, P. Rossi, N. Guler, William Brooks, Christian Weiss, A.V. Stavinsky, M. R. Niroula, R. W. Gothe, S. Boiarinov, W. Kim, M. Mirazita, W. J. Briscoe, L. Casey, G. Gavalian, C. Hanretty, S. Tkachenko, S. Anefalos Pereira, G. Niculescu, P. Nadel-Turonski, N. Benmouna, J. P. Ball, Tsutomu Mibe, Y. Prok, D. S. Carman, A. V. Skabelin, A. Cazes, Maryam Moteabbed, Hall Crannell, Bernhard Mecking, D. J. Tedeschi, M. Ripani, E. Pasyuk, V. Crede, Shifeng Chen, G. Rosner, K. V. Dharmawardane, J. R. Calarco, S. A. Dytman, I. Bedlinskiy, B. B. Niczyporuk, L. Guo, M. Ungaro, N. Pivnyuk, D. G. Crabb, R. A. Schumacher, M. Khandaker, S. Barrow, P. Mattione, M. S. Saini, P. Eugenio, M. Taiuti, K. Joo, G. S. Mutchler, Michael Vineyard, D. Cords, L. Graham, C. I O Gordon, A. Yegneswaran, M. Yurov, J. T. Goetz, S. Mehrabyan, S. Bültmann, V. Sapunenko, P. Collins, Dinko Pocanic, J. J. Melone, M. Osipenko, S. Procureur, T. A. Forest, C. Bookwalter, G. Riccardi, S. Stepanyan, S. E. Kuhn, Kalvir S. Dhuga, C. Butuceanu, J. Pierce, Avraham Klein, C. Tur, G. E. Dodge, L. Todor, H. Y. Lu, P. V. Degtyarenko, M. J. Amaryan, D. Protopopescu, M. MacCormick, I. Hleiqawi, S. Pozdniakov, I. Niculescu, D. Lawrence, S. L. Careccia, D. Schott, K. L. Giovanetti, Larry Weinstein, D. Doughty, D. Heddle, Y. Ilieva, B. Moreno, R. A. Miskimen, B. McKinnon, D. Branford, J. M. Laget, N. Gevorgyan, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, Z. Krahn, N. Baillie, Laird Kramer, Gerard Gilfoyle, D. Sokhan, A. Fradi, N. Markov, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, K. S. Egiyan, K. Mikhailov, P. Stoler, and K. Hicks

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Vector meson dominance, 01 natural sciences, Helicity, Gluon, 0103 physical sciences, Exponent, Vector meson, 010306 general physics, Nucleon, Exchange model
Abstract

Electroproduction of exclusive \ensuremath{\phi} vector mesons has been studied with the CLAS detector in the kinematic range $1.4\ensuremath{\leqslant}{Q}^{2}\ensuremath{\leqslant}3.8$ GeV${}^{2},0.0\ensuremath{\leqslant}{t}^{'}\ensuremath{\leqslant}3.6$ GeV${}^{2}$, and $2.0\ensuremath{\leqslant}W\ensuremath{\leqslant}3.0$ GeV. The scaling exponent for the total cross section as $1/({Q}^{2}+{M}_{\ensuremath{\phi}}^{2}){}^{n}$ was determined to be $n=2.49\ifmmode\pm\else\textpm\fi{}0.33$. The slope of the four-momentum transfer ${t}^{'}$ distribution is ${b}_{\ensuremath{\phi}}=0.98\ifmmode\pm\else\textpm\fi{}0.17$ GeV${}^{\ensuremath{-}2}$. Under the assumption of $s$-channel helicity conservation, we determine the ratio of longitudinal to transverse cross sections to be $R=0.86\ifmmode\pm\else\textpm\fi{}0.24$. A two-gluon exchange model is able to reproduce the main features of the data.

Published
2008

47. Ratios ofN15/C12andHe4/C12inclusive electroproduction cross sections in the nucleon resonance region

Author

K. S. Egiyan, L. Guo, K. Mikhailov, Calarco, P. Stoler, K. Hicks, Susan Taylor, M. Ungaro, C. D. Keith, J. Donnelly, G. Asryan, O. P. Dzyubak, R. A. Niyazov, H. Egiyan, P. Corvisiero, C. E. Hyde-Wright, Y. Ilieva, R. A. Miskimen, G. Ricco, M. Amarian, E. Wolin, B. Zhao, B. McKinnon, R. Fatemi, S. Strauch, Laird Kramer, K. Park, B. B. Niczyporuk, P. Dragovitsch, Nikolay Shvedunov, J. P. Ball, Y. Prok, D. S. Carman, K. Joo, L. M. Qin, R. Suleiman, D. Branford, N. Pivnyuk, Shifeng Chen, A. V. Vlassov, Sergey Kuleshov, J. Yun, D. Cords, M. Mirazita, D. G. Crabb, J. M. Laget, M. Bektasoglu, G. S. Mutchler, S. Niccolai, A. Yegneswaran, M. Battaglieri, Niroula, A. Fradi, M. Nozar, N. A. Baltzell, J. Hardie, P. Eugenio, H. G. Juengst, S. A. Morrow, R. De Vita, O. Pogorelko, C. Djalali, Kubarovsky, C. Paterson, Friedrich Klein, K. A. Griffioen, R. J. Feuerbach, N. Markov, K. Livingston, M. Klusman, M. Taiuti, A.V. Stavinsky, N. Kalantarians, Brian Raue, F. W. Hersman, R. Bradford, K. Lukashin, Marco A. Huertas, D. J. Tedeschi, J. Langheinrich, A. I. Ostrovidov, A. C S Lima, J. T. Goetz, J. Shaw, E. Polli, S. S. Stepanyan, Crede, S. A. Philips, P. Collins, D. G. Ireland, Michael Wood, K. Hafidi, I. Bedlinskiy, Batourine, Elton Smith, Gerard Gilfoyle, Mestayer, Volker D. Burkert, V. S. Serov, L. C. Dennis, A. S. Biselli, N. Guler, B. E. Bonner, H. Avakian, B. Carnahan, G. Gavalian, S. Tkachenko, M. Anghinolfi, N. Benmouna, M. Ripani, Kwangsoo Kim, J. Kuhn, J. Zhang, S Anefalos, R. W. Gothe, G. Riccardi, A. Cazes, James Mueller, J. W C McNabb, Maryam Moteabbed, Bernhard Mecking, J. D. Kellie, S. Barrow, C. Butuceanu, K. V. Dharmawardane, E. Pasyuk, H. Bagdasaryan, Mokeev, Cynthia Marie Hadjidakis, E. De Sanctis, P. D. Rubin, K. Y. Kim, Y. G. Sharabian, M. Guidal, S. A. Dytman, R. G. Fersch, Michael Dugger, H. O. Funsten, L. Todor, N. Baillie, D. I. Sober, D. Protopopescu, M. Holtrop, S. Pozdniakov, M. Garçon, Hong Lu, Sbr Ultmann, Dinko Pocanic, Sylvain Bouchigny, P. L. Cole, P. Rossi, S. E. Kuhn, M. Bellis, J. Lachniet, H. Denizli, A. Tkabladze, D. Rowntree, Sapunenko, R. S. Hakobyan, A. V. Skabelin, P. Nadel-Turonski, Tsutomu Mibe, R. C. Minehart, C. A. Meyer, G. V. Fedotov, B. E. Stokes, G. S. Adams, D. P. Weygand, U. Thoma, M. Khandaker, L. C. Smith, B. S. Ishkhanov, D. Doughty, D. Heddle, Gyurjyan, W. Kim, S. Stepanyan, G. Niculescu, M. MacCormick, I. Hleiqawi, G. Rosner, R. Nasseripour, P. Bosted, S. L. Careccia, K. L. Giovanetti, Larry Weinstein, P. Coltharp, M. M. Ito, M. Osipenko, F. Sabatié, M. Guillo, K. Beard, L. Elouadrhiri, A. Deur, W. K. Brooks, R. A. Schumacher, G. V. O'Rielly, E. Golovatch, L. Morand, T. A. Forest, J. Pierce, Avraham Klein, Z. W. Zhao, J. P. Cummings, Hall Crannell, M. Kossov, D. G. Jenkins, G. E. Dodge, P. V. Degtyarenko, S. McAleer, F. X. Girod, I. Niculescu, D. Lawrence, J. W. Price, R. De Masi, Ji Li, E. L. Isupov, Michael L. Williams, S. Boiarinov, Michael Vineyard, B. M. Preedom, Lorenzo Zana, J. P. Santoro, H. S. Jo, and C. Salgado

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Scattering, Hadron, Carbon-12, Deep inelastic scattering, 01 natural sciences, Nuclear physics, Baryon, Helium-4, 0103 physical sciences, Phenomenological model, Atomic physics, 010306 general physics, Nucleon
Abstract

The (W,Q{sup 2}) dependence of the ratio of inclusive electron scattering cross sections for {sup 15}N/{sup 12}C was determined in the kinematic ranges 0.8

Published
2008

48. Polarized structure functionσLT'forH1(e→,e'K+)Λin the nucleon resonance region

Author

L. C. Dennis, B. E. Bonner, S. McAleer, F. X. Girod, L. Blaszczyk, H. Avakian, D. Sharov, D. Lawrence, P. Stoler, K. Hicks, K. S. Egiyan, Laird Kramer, D. Doughty, L. C. Smith, E. Munevar, V. Mokeev, K. Mikhailov, Elton Smith, J. Langheinrich, S. S. Stepanyan, S. A. Philips, W. J. Briscoe, E. Pasyuk, B. S. Ishkhanov, D. P. Watts, S. A. Dytman, R. A. Schumacher, P. Eugenio, D. Heddle, H. Egiyan, J. W. Price, M. F. Vineyard, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Nadel-Turonski, Tsutomu Mibe, H. G. Juengst, P. Corvisiero, E. Wolin, M. Taiuti, M. Anghinolfi, M. Kossov, James Mueller, E. De Sanctis, M. R. Niroula, J. P. Ball, M. Battaglieri, Y. Ilieva, P. D. Rubin, Y. G. Sharabian, A.V. Stavinsky, D. S. Carman, Patrick Girard, W. Kim, T. A. Forest, G. Niculescu, J. Lachniet, D. I. Sober, R. J. Feuerbach, Michael Wood, A. I. Ostrovidov, V. Sapunenko, L. Casey, Dinko Pocanic, R. Bradford, K. Lukashin, D. J. Tedeschi, K. Park, C. Hanretty, S. Stepanyan, K. Hafidi, D. G. Crabb, J. Pierce, V. S. Serov, S. E. Kuhn, Avraham Klein, E. Anciant, B. E. Stokes, B. B. Niczyporuk, I. Bedlinskiy, G. Ricco, D. G. Ireland, B. Moreno, G. E. Dodge, H. Y. Lu, P. V. Degtyarenko, N. Pivnyuk, Volker D. Burkert, A. S. Biselli, G. Audit, C. E. Hyde-Wright, R. Fatemi, A. V. Vlassov, R. De Vita, Z. W. Zhao, V. Kuznetsov, K. Joo, S. Procureur, Maryam Moteabbed, B. Zhao, D. G. Jenkins, Bernhard Mecking, Z. Krahn, Shifeng Chen, D. Sayre, S. Strauch, P. Collins, D. Protopopescu, I. Niculescu, M. Khandaker, S. Pozdniakov, Sylvain Bouchigny, J. J. Manak, P. Rossi, N. Baillie, S. Anefalos Pereira, A. Fradi, C. Cetina, A. Shafi, P. Dragovitsch, P. Mattione, Friedrich Klein, Kwangsoo Kim, R. A. Miskimen, B. McKinnon, V. P. Kubarovsky, G. Riccardi, J. Salamanca, Sergey Kuleshov, M. Osipenko, R. De Masi, Brian Raue, D. Branford, M. Mirazita, J. M. Laget, J. W C McNabb, S. A. Morrow, C. Djalali, G. S. Mutchler, M. Bektasoglu, S. Niccolai, F. Sabatié, N. Gevorgyan, C. Butuceanu, K. Beard, F. W. Hersman, N. A. Baltzell, J. T. Goetz, K. Livingston, D. S. Dale, N. Markov, O. Pogorelko, P. Coltharp, V. Crede, K. A. Griffioen, R. Dickson, J. Hardie, M. J. Amaryan, Kalvir S. Dhuga, P. Ambrozewicz, Gerard Gilfoyle, M. Nozar, D. Sokhan, M. MacCormick, M. Bellis, I. Hleiqawi, M. M. Ito, S. L. Careccia, J. Kuhn, R. W. Gothe, G. Gavalian, N. Guler, J. R. Calarco, G. A. Peterson, S. Simionatto, J. D. Kellie, S. Taylor, S. Tkachenko, K. Y. Kim, K. L. Giovanetti, B. Asavapibhop, J. P. Santoro, Roy Thompson, Larry Weinstein, S. Barrow, N. Benmouna, M. Ripani, M. Guidal, M. Guillo, L. Cheng, M. D. Mestayer, G. Rosner, R. Nasseripour, Nikolay Shvedunov, J. Hu, E. L. Isupov, L. Elouadrhiri, M. Holtrop, Michael L. Williams, S. Boiarinov, I. I. Strakovsky, B. M. Preedom, A. Deur, Lorenzo Zana, N. Kalantarians, H. Hakobyan, H. S. Jo, Gerald Feldman, Michael Dugger, W. K. Brooks, K. Wang, H. O. Funsten, C. Salgado, B. L. Berman, L. M. Qin, C. Paterson, Thierry Auger, M. Garçcon, J. R. Johnstone, V. Gyurjyan, J. Zhang, H. Bagdasaryan, L. Guo, M. Ungaro, A. Tkabladze, J. Yun, D. Cords, L. El Fassi, A. Yegneswaran, P. L. Cole, Y. Prok, Barry Ritchie, R. C. Minehart, Kei Moriya, C. A. Meyer, G. V. Fedotov, D. P. Weygand, A. V. Skabelin, and N. Dashyan

Subjects
Physics, Nuclear and High Energy Physics, Angular range, 010308 nuclear & particles physics, Hydrogen-1, Structure function, Hyperon, Sigma, Resonance, Lambda, 01 natural sciences, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The first measurements of the polarized structure function {sigma}{sub LT{sup '}} for the reaction {sup 1}H(e-vector,e{sup '}K{sup +}){lambda} in the nucleon resonance region are reported. Measurements are included from threshold up to W=2.05 GeV for central values of Q{sup 2} of 0.65 and 1.00 GeV{sup 2}, and nearly the entire kaon center-of-mass angular range. {sigma}{sub LT{sup '}} is the imaginary part of the longitudinal-transverse response and is expected to be sensitive to interferences between competing intermediate s-channel resonances, as well as resonant and nonresonant processes. The results for {sigma}{sub LT{sup '}} are comparable in magnitude to previously reported results from CLAS for {sigma}{sub LT}, the real part of the same response. An intriguing sign change in {sigma}{sub LT{sup '}} is observed in the high Q{sup 2} data at W{approx_equal}1.9 GeV. Comparisons to several existing model predictions are shown.

Published
2008

49. Measurement ofep→epπ0beam spin asymmetries above the resonance region

Author

R. De Masi, M. Garçon, B. Zhao, M. J. Amaryan, P. Ambrozewicz, M. Anghinolfi, G. Asryan, H. Avakian, H. Bagdasaryan, N. Baillie, J. Ball, J. P. Ball, N. A. Baltzell, V. Batourine, M. Battaglieri, I. Bedlinskiy, M. Bellis, N. Benmouna, B. L. Berman, P. Bertin, A. S. Biselli, L. Blaszczyk, S. Bouchigny, S. Boiarinov, R. Bradford, D. Branford, W. J. Briscoe, W. K. Brooks, S. Bültmann, V. D. Burkert, C. Butuceanu, J. R. Calarco, S. L. Careccia, D. S. Carman, L. Casey, S. Chen, L. Cheng, P. L. Cole, P. Collins, P. Coltharp, D. Crabb, V. Crede, N. Dashyan, E. De Sanctis, R. De Vita, P. V. Degtyarenko, A. Deur, K. V. Dharmawardane, R. Dickson, C. Djalali, G. E. Dodge, J. Donnelly, D. Doughty, M. Dugger, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, G. Feldman, A. Fradi, H. Funsten, G. Gavalian, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, A. Gonenc, R. W. Gothe, K. A. Griffioen, M. Guidal, N. Guler, L. Guo, V. Gyurjyan, K. Hafidi, H. Hakobyan, C. Hanretty, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, C. E. Hyde-Wright, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, M. M. Ito, D. Jenkins, H. S. Jo, J. R. Johnstone, K. Joo, H. G. Juengst, N. Kalantarians, J. D. Kellie, M. Khandaker, W. Kim, A. Klein, F. J. Klein, A. V. Klimenko, M. Kossov, Z. Krahn, L. H. Kramer, V. Kubarovsky, J. Kuhn, S. E. Kuhn, S. V. Kuleshov, J. Lachniet, J. M. Laget, J. Langheinrich, D. Lawrence, T. Lee, K. Livingston, H. Y. Lu, M. MacCormick, N. Markov, P. Mattione, M. Mazouz, B. McKinnon, B. A. Mecking, M. D. Mestayer, C. A. Meyer, T. Mibe, B. Michel, K. Mikhailov, M. Mirazita, R. Miskimen, V. Mokeev, B. Moreno, K. Moriya, S. A. Morrow, M. Moteabbed, E. Munevar, G. S. Mutchler, P. Nadel-Turonski, R. Nasseripour, S. Niccolai, G. Niculescu, I. Niculescu, B. B. Niczyporuk, M. R. Niroula, R. A. Niyazov, M. Nozar, M. Osipenko, A. I. Ostrovidov, K. Park, E. Pasyuk, C. Paterson, S. Anefalos Pereira, J. Pierce, N. Pivnyuk, D. Pocanic, O. Pogorelko, S. Pozdniakov, J. W. Price, S. Procureur, Y. Prok, D. Protopopescu, B. A. Raue, G. Ricco, M. Ripani, B. G. Ritchie, F. Ronchetti, G. Rosner, P. Rossi, F. Sabatié, J. Salamanca, C. Salgado, J. P. Santoro, V. Sapunenko, R. A. Schumacher, V. S. Serov, Y. G. Sharabian, D. Sharov, N. V. Shvedunov, E. S. Smith, L. C. Smith, D. I. Sober, D. Sokhan, A. Stavinsky, S. Stepanyan, S. S. Stepanyan, B. E. Stokes, P. Stoler, I. I. Strakovsky, S. Strauch, M. Taiuti, D. J. Tedeschi, A. Tkabladze, S. Tkachenko, C. Tur, M. Ungaro, M. F. Vineyard, A. V. Vlassov, E. Voutier, D. P. Watts, L. B. Weinstein, D. P. Weygand, M. Williams, E. Wolin, M. H. Wood, A. Yegneswaran, L. Zana, J. Zhang, and Z. W. Zhao

Subjects
Physics, Nuclear and High Energy Physics, Photon, Spectrometer, 010308 nuclear & particles physics, media_common.quotation_subject, Parton, 01 natural sciences, Asymmetry, Nuclear physics, Formalism (philosophy of mathematics), Amplitude, 0103 physical sciences, Cathode ray, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract

The beam spin asymmetry (BSA) in the exclusive reaction ep->ep pi0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer(CLAS). The xB, Q2, t and phi dependences of the pi0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sin(phi) function and their amplitudes are extracted. Overall, they are of the order of 0.04 - 0.11 and roughly independent of t. This is the signature of a non-zero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as the extension of a Regge formalism at high photon virtualities, are discussed.

Published
2008

50. Light Vector Mesons in the Nuclear Medium

Author

V. Crede, S. McAleer, L. Blaszczyk, J. R. Calarco, B. L. Berman, E. De Sanctis, S. Tkachenko, M. Taiuti, R. A. Schumacher, Michael Wood, A. I. Ostrovidov, G. Asryan, C. I O Gordon, K. Hafidi, K. Park, C. Paterson, J. W. Price, O. P. Dzyubak, R. A. Niyazov, V. S. Serov, L. C. Dennis, D. G. Ireland, B. G. Ritchie, B. E. Stokes, J. Kuhn, M. R. Niroula, Cynthia Marie Hadjidakis, M. J. Amaryan, H. Avakian, M. MacCormick, I. Hleiqawi, Volker D. Burkert, G. S. Adams, S. L. Careccia, A. S. Biselli, S. Stepanyan, D. Sharov, A. V. Vlassov, Philip L. Cole, Larry Weinstein, J. Pierce, Avraham Klein, Chaden Djalali, K.H. Hicks, D. J. Tedeschi, K. Joo, Sylvain Bouchigny, G. S. Mutchler, Michael Dugger, W. Kim, Gerard Gilfoyle, D. Sokhan, H. S. Jo, K. S. Egiyan, J. Hardie, Friedrich Klein, J. P. Cummings, Laird Kramer, K. Livingston, S. A. Dytman, W. K. Brooks, B. Carnahan, S. Niccolai, H. O. Funsten, P. Collins, Ulrich Mosel, Z. W. Zhao, I. Bedlinskiy, H. G. Juengst, G. Niculescu, R. Nasseripour, K. Mikhailov, R. A. Miskimen, B. McKinnon, H. Hakobyan, S. Anefalos Pereira, D. G. Jenkins, P. Coltharp, Hall Crannell, A.V. Stavinsky, P. Eugenio, R. W. Gothe, V. Sapunenko, M. Bektasoglu, C. Salgado, Dinko Pocanic, M. M. Ito, D. Branford, V. Gyurjyan, P. Khetarpal, A. Fradi, M. Holtrop, M. Kossov, J. M. Laget, D. P. Weygand, Y. Ilieva, V. P. Kubarovsky, R. De Vita, L. C. Smith, E. Munevar, G. E. Dodge, B. S. Ishkhanov, P. Nadel-Turonski, H. Bagdasaryan, P. V. Degtyarenko, N. Guler, S. E. Kuhn, Federico Ronchetti, J. J. Melone, K. Moriya, C. Hanretty, I. Niculescu, D. Lawrence, J. D. Kellie, Victor Mokeev, J. R. Johnstone, L. Guo, M. Ungaro, Latifa Elouadrhiri, G. Rosner, J. Lachniet, A. Tkabladze, M. Guidal, A. Yegneswaran, R. C. Minehart, S. Barrow, C. Tur, P. Rossi, J. Langheinrich, S. S. Stepanyan, E. Pasyuk, J. Zhang, C. A. Meyer, S. Mehrabyan, F. X. Girod, Baile Zhang, G. V. Fedotov, G. Gavalian, R. S. Hakobyan, R. Dickson, M. Ripani, L. El Fassi, D. Doughty, Z. Krahn, N. Benmouna, G. Riccardi, B. A. Raue, M. Osipenko, C. Butuceanu, Tsutomu Mibe, L. Cheng, Shifeng Chen, N. Baillie, Daniel S. Carman, F. Sabatié, Nikolay Shvedunov, K. L. Giovanetti, S. V. Kuleshov, D. Protopopescu, G. Ricco, S. Pozdniakov, M. Garçon, E. Wolin, C. E. Hyde-Wright, O. Pogorelko, J. Ball, N. Kalantarians, M. Khandaker, D. G. Crabb, M. Nozar, B. Zhao, H. Denizli, H. Y. Lu, J. T. Goetz, F. W. Hersman, M. Mirazita, Elton Smith, N. Dashyan, James Mueller, Alexei V. Klimenko, Y. Prok, I. I. Strakovsky, Y. G. Sharabian, P. Muehlich, A. Deur, Ji Li, M. D. Mestayer, R. J. Feuerbach, E. L. Isupov, Michael L. Williams, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, S. Boiarinov, B. M. Preedom, Lorenzo Zana, J. P. Santoro, M. Battaglieri, D. P. Watts, H. Egiyan, Gerald Feldman, N. A. Baltzell, N. Markov, R. Bradford, K. A. Griffioen, N. Hassall, M. Bellis, J. Salamanca, P. Mattione, J. W C McNabb, M. Anghinolfi, L. Casey, B. B. Niczyporuk, Michael Vineyard, N. Pivnyuk, W. J. Briscoe, L. Todor, S. A. Morrow, S. Strauch, P. Ambrozewicz, P. Stoler, D. I. Sober, Thomas Jefferson National Accelerator Facility (Jefferson Lab), 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), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and 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)

Subjects
Nuclear and High Energy Physics, Particle physics, Rho meson, Meson, Nuclear Theory, FOS: Physical sciences, light vector mesons, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, chiral symmetry, Spectral line, Nuclear physics, ENHANCEMENT, CLAS, 0103 physical sciences, 11.30.Rd, 14.40.Cs, 24.85.+p, QCD SUM-RULES, Invariant mass, RHO-MESON, Nuclear Experiment (nucl-ex), 010306 general physics, in-medium modifications, Nuclear Experiment, Physics, AU COLLISIONS, QCD sum rules, CEBAF, 010308 nuclear & particles physics, QCD SUM-RULES, RHO-MESON, SPECTRAL-FUNCTION, AU COLLISIONS, OMEGA-MESONS, MATTER, CLAS, ENHANCEMENT, SYSTEM, CEBAF, Nuclear matter, SPECTRAL-FUNCTION, Deuterium, Mass spectrum, High Energy Physics::Experiment, MATTER, SYSTEM, OMEGA-MESONS
Abstract

The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\rho$ meson mass spectrum was extracted after the $\omega$ and $\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional broadening and Fermi motion., Comment: 15 pages, 18 figures, 3 tables

Published
2008

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