A. Gasparian - Hampton University

A. Gasparian
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Name
A. Gasparian
Affiliation
Hampton University
City
Hampton
Country
United States

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Nuclear Experiment (20)
 
High Energy Physics - Experiment (9)
 
High Energy Physics - Phenomenology (5)
 
Nuclear Theory (4)
 
Physics - Instrumentation and Detectors (3)
 
Cosmology and Nongalactic Astrophysics (1)

Publications Authored By A. Gasparian

2017Jan
Authors: GlueX Collaboration, H. Al Ghoul, E. G. Anassontzis, A. Austregesilo, F. Barbosa, A. Barnes, T. D. Beattie, D. W. Bennett, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, W. K. Brooks, B. E. Cannon, O. Chernyshov, E. Chudakov, V. Crede, M. M. Dalton, A. Deur, S. Dobbs, A. Dolgolenko, M. Dugger, R. Dzhygadlo, H. Egiyan, P. Eugenio, C. Fanelli, A. M. Foda, J. Frye, S. Furletov, L. Gan, A. Gasparian, A. Gerasimov, N. Gevorgyan, K. Goetzen, V. S. Goryachev, L. Guo, H. Hakobyan, J. Hardin, A. Henderson, G. M. Huber, D. G. Ireland, M. M. Ito, N. S. Jarvis, R. T. Jones, V. Kakoyan, M. Kamel, F. J. Klein, R. Kliemt, C. Kourkoumeli, S. Kuleshov, I. Kuznetsov, M. Lara, I. Larin, D. Lawrence, W. I. Levine, K. Livingston, G. J. Lolos, V. Lyubovitskij, D. Mack, P. T. Mattione, V. Matveev, M. McCaughan, M. McCracken, W. McGinley, J. McIntyre, R. Mendez, C. A. Meyer, R. Miskimen, R. E. Mitchell, F. Mokaya, K. Moriya, F. Nerling, G. Nigmatkulov, N. Ochoa, A. I. Ostrovidov, Z. Papandreou, M. Patsyuk, R. Pedroni, M. R. Pennington, L. Pentchev, K. J. Peters, E. Pooser, B. Pratt, Y. Qiang, J. Reinhold, B. G. Ritchie, L. Robison, D. Romanov, C. Salgado, R. A. Schumacher, C. Schwarz, J. Schwiening, A. Yu. Semenov, I. A. Semenova, K. K. Seth, M. R. Shepherd, E. S. Smith, D. I. Sober, A. Somov, S. Somov, O. Soto, N. Sparks, M. J. Staib, J. R. Stevens, I. I. Strakovsky, A. Subedi, V. Tarasov, S. Taylor, A. Teymurazyan, I. Tolstukhin, A. Tomaradze, A. Toro, A. Tsaris, G. Vasileiadis, I. Vega, N. K. Walford, D. Werthmuller, T. Whitlatch, M. Williams, E. Wolin, T. Xiao, J. Zarling, Z. Zhang, B. Zihlmann, V. Mathieu, J. Nys

We report measurements of the photon beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\to p\pi^0$ and $\vec{\gamma}p\to p\eta $ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $\pi^0$ measurements and are the first $\eta$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models. Read More

2016Jun
Affiliations: 1HKS, 2HKS, 3HKS, 4HKS, 5HKS, 6HKS, 7HKS, 8HKS, 9HKS, 10HKS, 11HKS, 12HKS, 13HKS, 14HKS, 15HKS, 16HKS, 17HKS, 18HKS, 19HKS, 20HKS, 21HKS, 22HKS, 23HKS, 24HKS, 25HKS, 26HKS, 27HKS, 28HKS, 29HKS, 30HKS, 31HKS, 32HKS, 33HKS, 34HKS, 35HKS, 36HKS, 37HKS, 38HKS, 39HKS, 40HKS, 41HKS, 42HKS, 43HKS, 44HKS, 45HKS, 46HKS, 47HKS, 48HKS, 49HKS, 50HKS, 51HKS, 52HKS, 53HKS, 54HKS, 55HKS, 56HKS, 57HKS, 58HKS, 59HKS, 60HKS, 61HKS, 62HKS, 63HKS, 64HKS, 65HKS, 66HKS, 67HKS, 68HKS, 69HKS, 70HKS, 71HKS, 72HKS, 73HKS, 74HKS, 75HKS, 76HKS, 77HKS, 78HKS, 79HKS, 80HKS, 81HKS, 82HKS, 83HKS, 84HKS, 85HKS, 86HKS

The missing mass spectroscopy of the $^{7}_{\Lambda}$He hypernucleus was performed, using the $^{7}$Li$(e,e^{\prime}K^{+})^{7}_{\Lambda}$He reaction at the Thomas Jefferson National Accelerator Facility Hall C. The $\Lambda$ binding energy of the ground state (1/2$^{+}$) was determined with a smaller error than that of the previous measurement, being $B_{\Lambda}$ = 5.55 $\pm$ 0. Read More

2015Dec

The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of $\pi^{0}$, $\eta$ and $\omega$ mesons. Read More

We propose to enhance the kaon identification capabilities of the GlueX detector by constructing an FDIRC (Focusing Detection of Internally Reflected Cherenkov) detector utilizing the decommissioned BaBar DIRC components. The GlueX FDIRC would significantly enhance the GlueX physics program by allowing one to search for and study hybrid mesons decaying into kaon final states. Such systematic studies of kaon final states are essential for inferring the quark flavor content of hybrid and conventional mesons. Read More

2014Jun
Authors: L. Tang1, C. Chen2, T. Gogami3, D. Kawama4, Y. Han5, L. Yuan6, A. Matsumura7, Y. Okayasu8, T. Seva9, V. M. Rodriguez10, P. Baturin11, A. Acha12, P. Achenbach13, A. Ahmidouch14, I. Albayrak15, D. Androic16, A. Asaturyan17, R. Asaturyan18, O. Ates19, R. Badui20, O. K. Baker21, F. Benmokhtar22, W. Boeglin23, J. Bono24, P. Bosted25, E. Brash26, P. Carter27, R. Carlini28, A. Chiba29, M. E. Christy30, L. Cole31, M. M. Dalton32, S. Danagoulian33, A. Daniel34, R. De Leo35, V. Dharmawardane36, D. Doi37, K. Egiyan38, M. Elaasar39, R. Ent40, H. Fenker41, Y. Fujii42, M. Furic43, M. Gabrielyan44, L. Gan45, F. Garibaldi46, D. Gaskell47, A. Gasparian48, E. F. Gibson49, P. Gueye50, O. Hashimoto51, D. Honda52, T. Horn53, B. Hu54, Ed V. Hungerford55, C. Jayalath56, M. Jones57, K. Johnston58, N. Kalantarians59, H. Kanda60, M. Kaneta61, F. Kato62, S. Kato63, M. Kawai64, C. Keppel65, H. Khanal66, M. Kohl67, L. Kramer68, K. J. Lan69, Y. Li70, A. Liyanage71, W. Luo72, D. Mack73, K. Maeda74, S. Malace75, A. Margaryan76, G. Marikyan77, P. Markowitz78, T. Maruta79, N. Maruyama80, V. Maxwell81, D. J. Millener82, T. Miyoshi83, A. Mkrtchyan84, H. Mkrtchyan85, T. Motoba86, S. Nagao87, S. N. Nakamura88, A. Narayan89, C. Neville90, G. Niculescu91, M. I. Niculescu92, A. Nunez93, Nuruzzaman94, H. Nomura95, K. Nonaka96, A. Ohtani97, M. Oyamada98, N. Perez99, T. Petkovic100, J. Pochodzalla101, X. Qiu102, S. Randeniya103, B. Raue104, J. Reinhold105, R. Rivera106, J. Roche107, C. Samanta108, Y. Sato109, B. Sawatzky110, E. K. Segbefia111, D. Schott112, A. Shichijo113, N. Simicevic114, G. Smith115, Y. Song116, M. Sumihama117, V. Tadevosyan118, T. Takahashi119, N. Taniya120, K. Tsukada121, V. Tvaskis122, M. Veilleux123, W. Vulcan124, S. Wells125, F. R. Wesselmann126, S. A. Wood127, T. Yamamoto128, C. Yan129, Z. Ye130, K. Yokota131, S. Zhamkochyan132, L. Zhu133
Affiliations: 1HKS - JLab E05-115 and E01-001 - Collaborations, 2HKS - JLab E05-115 and E01-001 - Collaborations, 3HKS - JLab E05-115 and E01-001 - Collaborations, 4HKS - JLab E05-115 and E01-001 - Collaborations, 5HKS - JLab E05-115 and E01-001 - Collaborations, 6HKS - JLab E05-115 and E01-001 - Collaborations, 7HKS - JLab E05-115 and E01-001 - Collaborations, 8HKS - JLab E05-115 and E01-001 - Collaborations, 9HKS - JLab E05-115 and E01-001 - Collaborations, 10HKS - JLab E05-115 and E01-001 - Collaborations, 11HKS - JLab E05-115 and E01-001 - Collaborations, 12HKS - JLab E05-115 and E01-001 - Collaborations, 13HKS - JLab E05-115 and E01-001 - Collaborations, 14HKS - JLab E05-115 and E01-001 - Collaborations, 15HKS - JLab E05-115 and E01-001 - Collaborations, 16HKS - JLab E05-115 and E01-001 - Collaborations, 17HKS - JLab E05-115 and E01-001 - Collaborations, 18HKS - JLab E05-115 and E01-001 - Collaborations, 19HKS - JLab E05-115 and E01-001 - Collaborations, 20HKS - JLab E05-115 and E01-001 - Collaborations, 21HKS - JLab E05-115 and E01-001 - Collaborations, 22HKS - JLab E05-115 and E01-001 - Collaborations, 23HKS - JLab E05-115 and E01-001 - Collaborations, 24HKS - JLab E05-115 and E01-001 - Collaborations, 25HKS - JLab E05-115 and E01-001 - Collaborations, 26HKS - JLab E05-115 and E01-001 - Collaborations, 27HKS - JLab E05-115 and E01-001 - Collaborations, 28HKS - JLab E05-115 and E01-001 - Collaborations, 29HKS - JLab E05-115 and E01-001 - Collaborations, 30HKS - JLab E05-115 and E01-001 - Collaborations, 31HKS - JLab E05-115 and E01-001 - Collaborations, 32HKS - JLab E05-115 and E01-001 - Collaborations, 33HKS - JLab E05-115 and E01-001 - Collaborations, 34HKS - JLab E05-115 and E01-001 - Collaborations, 35HKS - JLab E05-115 and E01-001 - Collaborations, 36HKS - JLab E05-115 and E01-001 - Collaborations, 37HKS - JLab E05-115 and E01-001 - Collaborations, 38HKS - JLab E05-115 and E01-001 - Collaborations, 39HKS - JLab E05-115 and E01-001 - Collaborations, 40HKS - JLab E05-115 and E01-001 - Collaborations, 41HKS - JLab E05-115 and E01-001 - Collaborations, 42HKS - JLab E05-115 and E01-001 - Collaborations, 43HKS - JLab E05-115 and E01-001 - Collaborations, 44HKS - JLab E05-115 and E01-001 - Collaborations, 45HKS - JLab E05-115 and E01-001 - Collaborations, 46HKS - JLab E05-115 and E01-001 - Collaborations, 47HKS - JLab E05-115 and E01-001 - Collaborations, 48HKS - JLab E05-115 and E01-001 - Collaborations, 49HKS - JLab E05-115 and E01-001 - Collaborations, 50HKS - JLab E05-115 and E01-001 - Collaborations, 51HKS - JLab E05-115 and E01-001 - Collaborations, 52HKS - JLab E05-115 and E01-001 - Collaborations, 53HKS - JLab E05-115 and E01-001 - Collaborations, 54HKS - JLab E05-115 and E01-001 - Collaborations, 55HKS - JLab E05-115 and E01-001 - Collaborations, 56HKS - JLab E05-115 and E01-001 - Collaborations, 57HKS - JLab E05-115 and E01-001 - Collaborations, 58HKS - JLab E05-115 and E01-001 - Collaborations, 59HKS - JLab E05-115 and E01-001 - Collaborations, 60HKS - JLab E05-115 and E01-001 - Collaborations, 61HKS - JLab E05-115 and E01-001 - Collaborations, 62HKS - JLab E05-115 and E01-001 - Collaborations, 63HKS - JLab E05-115 and E01-001 - Collaborations, 64HKS - JLab E05-115 and E01-001 - Collaborations, 65HKS - JLab E05-115 and E01-001 - Collaborations, 66HKS - JLab E05-115 and E01-001 - Collaborations, 67HKS - JLab E05-115 and E01-001 - Collaborations, 68HKS - JLab E05-115 and E01-001 - Collaborations, 69HKS - JLab E05-115 and E01-001 - Collaborations, 70HKS - JLab E05-115 and E01-001 - Collaborations, 71HKS - JLab E05-115 and E01-001 - Collaborations, 72HKS - JLab E05-115 and E01-001 - Collaborations, 73HKS - JLab E05-115 and E01-001 - Collaborations, 74HKS - JLab E05-115 and E01-001 - Collaborations, 75HKS - JLab E05-115 and E01-001 - Collaborations, 76HKS - JLab E05-115 and E01-001 - Collaborations, 77HKS - JLab E05-115 and E01-001 - Collaborations, 78HKS - JLab E05-115 and E01-001 - Collaborations, 79HKS - JLab E05-115 and E01-001 - Collaborations, 80HKS - JLab E05-115 and E01-001 - Collaborations, 81HKS - JLab E05-115 and E01-001 - Collaborations, 82HKS - JLab E05-115 and E01-001 - Collaborations, 83HKS - JLab E05-115 and E01-001 - Collaborations, 84HKS - JLab E05-115 and E01-001 - Collaborations, 85HKS - JLab E05-115 and E01-001 - Collaborations, 86HKS - JLab E05-115 and E01-001 - Collaborations, 87HKS - JLab E05-115 and E01-001 - Collaborations, 88HKS - JLab E05-115 and E01-001 - Collaborations, 89HKS - JLab E05-115 and E01-001 - Collaborations, 90HKS - JLab E05-115 and E01-001 - Collaborations, 91HKS - JLab E05-115 and E01-001 - Collaborations, 92HKS - JLab E05-115 and E01-001 - Collaborations, 93HKS - JLab E05-115 and E01-001 - Collaborations, 94HKS - JLab E05-115 and E01-001 - Collaborations, 95HKS - JLab E05-115 and E01-001 - Collaborations, 96HKS - JLab E05-115 and E01-001 - Collaborations, 97HKS - JLab E05-115 and E01-001 - Collaborations, 98HKS - JLab E05-115 and E01-001 - Collaborations, 99HKS - JLab E05-115 and E01-001 - Collaborations, 100HKS - JLab E05-115 and E01-001 - Collaborations, 101HKS - JLab E05-115 and E01-001 - Collaborations, 102HKS - JLab E05-115 and E01-001 - Collaborations, 103HKS - JLab E05-115 and E01-001 - Collaborations, 104HKS - JLab E05-115 and E01-001 - Collaborations, 105HKS - JLab E05-115 and E01-001 - Collaborations, 106HKS - JLab E05-115 and E01-001 - Collaborations, 107HKS - JLab E05-115 and E01-001 - Collaborations, 108HKS - JLab E05-115 and E01-001 - Collaborations, 109HKS - JLab E05-115 and E01-001 - Collaborations, 110HKS - JLab E05-115 and E01-001 - Collaborations, 111HKS - JLab E05-115 and E01-001 - Collaborations, 112HKS - JLab E05-115 and E01-001 - Collaborations, 113HKS - JLab E05-115 and E01-001 - Collaborations, 114HKS - JLab E05-115 and E01-001 - Collaborations, 115HKS - JLab E05-115 and E01-001 - Collaborations, 116HKS - JLab E05-115 and E01-001 - Collaborations, 117HKS - JLab E05-115 and E01-001 - Collaborations, 118HKS - JLab E05-115 and E01-001 - Collaborations, 119HKS - JLab E05-115 and E01-001 - Collaborations, 120HKS - JLab E05-115 and E01-001 - Collaborations, 121HKS - JLab E05-115 and E01-001 - Collaborations, 122HKS - JLab E05-115 and E01-001 - Collaborations, 123HKS - JLab E05-115 and E01-001 - Collaborations, 124HKS - JLab E05-115 and E01-001 - Collaborations, 125HKS - JLab E05-115 and E01-001 - Collaborations, 126HKS - JLab E05-115 and E01-001 - Collaborations, 127HKS - JLab E05-115 and E01-001 - Collaborations, 128HKS - JLab E05-115 and E01-001 - Collaborations, 129HKS - JLab E05-115 and E01-001 - Collaborations, 130HKS - JLab E05-115 and E01-001 - Collaborations, 131HKS - JLab E05-115 and E01-001 - Collaborations, 132HKS - JLab E05-115 and E01-001 - Collaborations, 133HKS - JLab E05-115 and E01-001 - Collaborations

Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using the $(e,e^{\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, the "tilt method", to dramatically suppress the large electromagnetic background, and allowed for a substantial increase in luminosity. Additionally, a new kaon spectrometer, HKS (E01-011), a new electron spectrometer, HES, and a new splitting magnet were added to produce precision, high-resolution hypernuclear spectroscopy. Read More

Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark sectors, each with their own beautiful structure, distinct particles, and forces. This review summarizes the physics motivation for dark sectors and the exciting opportunities for experimental exploration. Read More

The primary motivation of the GlueX experiment is to search for and ultimately study the pattern of gluonic excitations in the meson spectrum produced in $\gamma p$ collisions. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons that have both exotic and non-exotic $J^{PC}$, corresponding to $q\bar{q}$ states ($q=u,$ $d,$ or $s$) coupled with a gluonic field. A thorough study of the hybrid spectrum, including the identification of the isovector triplet, with charges 0 and $\pm1$, and both isoscalar members, $|s\bar{s}\ >$ and $|u\bar{u}\ > + |d\bar{d}\ >$, for each predicted hybrid combination of $J^{PC}$, may only be achieved by conducting a systematic amplitude analysis of many different hadronic final states. Read More

The lifetime of a Lambda particle embedded in a nucleus (hypernucleus) decreases from that of free Lambda decay due to the opening of the Lambda N to NN weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. The present paper reports a direct measurement of the lifetime of medium-heavy hypernuclei produced with a photon-beam from Fe, Cu, Ag, and Bi targets. Read More

The primary motivation of the GlueX experiment is to search for and ultimately study the pattern of gluonic excitations in the meson spectrum produced in gamma p collisions. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons that have both exotic and non-exotic JPC, corresponding to q q-bar (q=u, d, or s) states coupled with a gluonic field. A thorough study of the hybrid spectrum, including the identification of the isovector triplet, with charges 0 and +-1, and both isoscalar members, |s s-bar> and |u u-bar> + |d d-bar>, for each predicted hybrid combination of JPC, may only be achieved by conducting a systematic amplitude analysis of many different hadronic final states. Read More

2012Jul
Affiliations: 1HKS, 2HKS, 3HKS, 4HKS, 5HKS, 6HKS, 7HKS, 8HKS, 9HKS, 10HKS, 11HKS, 12HKS, 13HKS, 14HKS, 15HKS, 16HKS, 17HKS, 18HKS, 19HKS, 20HKS, 21HKS, 22HKS, 23HKS, 24HKS, 25HKS, 26HKS, 27HKS, 28HKS, 29HKS, 30HKS, 31HKS, 32HKS, 33HKS, 34HKS, 35HKS, 36HKS, 37HKS, 38HKS, 39HKS, 40HKS, 41HKS, 42HKS, 43HKS, 44HKS, 45HKS, 46HKS, 47HKS, 48HKS, 49HKS, 50HKS, 51HKS, 52HKS, 53HKS, 54HKS, 55HKS, 56HKS, 57HKS, 58HKS, 59HKS, 60HKS, 61HKS, 62HKS, 63HKS, 64HKS, 65HKS, 66HKS, 67HKS, 68HKS, 69HKS, 70HKS, 71HKS, 72HKS, 73HKS, 74HKS, 75HKS, 76HKS, 77HKS, 78HKS, 79HKS, 80HKS, 81HKS, 82HKS, 83HKS, 84HKS, 85HKS, 86HKS, 87HKS, 88HKS, 89HKS, 90HKS, 91HKS, 92HKS, 93HKS

An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 Lambda, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. Read More

2012May
Authors: H. Fonvieille1, G. Laveissiere2, N. Degrande3, S. Jaminion4, C. Jutier5, L. Todor6, R. Di Salvo7, L. Van Hoorebeke8, L. C. Alexa9, B. D. Anderson10, K. A. Aniol11, K. Arundell12, G. Audit13, L. Auerbach14, F. T. Baker15, M. Baylac16, J. Berthot17, P. Y. Bertin18, W. Bertozzi19, L. Bimbot20, W. U. Boeglin21, E. J. Brash22, V. Breton23, H. Breuer24, E. Burtin25, J. R. Calarco26, L. S. Cardman27, C. Cavata28, C. -C. Chang29, J. -P. Chen30, E. Chudakov31, E. Cisbani32, D. S. Dale33, C. W. deJager34, R. De Leo35, A. Deur36, N. d'Hose37, G. E. Dodge38, J. J. Domingo39, L. Elouadrhiri40, M. B. Epstein41, L. A. Ewell42, J. M. Finn43, K. G. Fissum44, G. Fournier45, B. Frois46, S. Frullani47, C. Furget48, H. Gao49, J. Gao50, F. Garibaldi51, A. Gasparian52, S. Gilad53, R. Gilman54, A. Glamazdin55, C. Glashausser56, J. Gomez57, V. Gorbenko58, P. Grenier59, P. A. M. Guichon60, J. O. Hansen61, R. Holmes62, M. Holtrop63, C. Howell64, G. M. Huber65, C. E. Hyde66, S. Incerti67, M. Iodice68, J. Jardillier69, M. K. Jones70, W. Kahl71, S. Kato72, A. T. Katramatou73, J. J. Kelly74, S. Kerhoas75, A. Ketikyan76, M. Khayat77, K. Kino78, S. Kox79, L. H. Kramer80, K. S. Kumar81, G. Kumbartzki82, M. Kuss83, A. Leone84, J. J. LeRose85, M. Liang86, R. A. Lindgren87, N. Liyanage88, G. J. Lolos89, R. W. Lourie90, R. Madey91, K. Maeda92, S. Malov93, D. M. Manley94, C. Marchand95, D. Marchand96, D. J. Margaziotis97, P. Markowitz98, J. Marroncle99, J. Martino100, K. McCormick101, J. McIntyre102, S. Mehrabyan103, F. Merchez104, Z. E. Meziani105, R. Michaels106, G. W. Miller107, J. Y. Mougey108, S. K. Nanda109, D. Neyret110, E. A. J. M. Offermann111, Z. Papandreou112, B. Pasquini113, C. F. Perdrisat114, R. Perrino115, G. G. Petratos116, S. Platchkov117, R. Pomatsalyuk118, D. L. Prout119, V. A. Punjabi120, T. Pussieux121, G. Quemener122, R. D. Ransome123, O. Ravel124, J. S. Real125, F. Renard126, Y. Roblin127, D. Rowntree128, G. Rutledge129, P. M. Rutt130, A. Saha131, T. Saito132, A. J. Sarty133, A. Serdarevic134, T. Smith135, G. Smirnov136, K. Soldi137, P. Sorokin138, P. A. Souder139, R. Suleiman140, J. A. Templon141, T. Terasawa142, R. Tieulent143, E. Tomasi-Gustaffson144, H. Tsubota145, H. Ueno146, P. E. Ulmer147, G. M. Urciuoli148, M. Vanderhaeghen149, R. L. J. Van der Meer150, R. Van De Vyver151, P. Vernin152, B. Vlahovic153, H. Voskanyan154, E. Voutier155, J. W. Watson156, L. B. Weinstein157, K. Wijesooriya158, R. Wilson159, B. B. Wojtsekhowski160, D. G. Zainea161, W. -M. Zhang162, J. Zhao163, Z. -L. Zhou164
Affiliations: 1The Jefferson Lab Hall A Collaboration, 2The Jefferson Lab Hall A Collaboration, 3The Jefferson Lab Hall A Collaboration, 4The Jefferson Lab Hall A Collaboration, 5The Jefferson Lab Hall A Collaboration, 6The Jefferson Lab Hall A Collaboration, 7The Jefferson Lab Hall A Collaboration, 8The Jefferson Lab Hall A Collaboration, 9The Jefferson Lab Hall A Collaboration, 10The Jefferson Lab Hall A Collaboration, 11The Jefferson Lab Hall A Collaboration, 12The Jefferson Lab Hall A Collaboration, 13The Jefferson Lab Hall A Collaboration, 14The Jefferson Lab Hall A Collaboration, 15The Jefferson Lab Hall A Collaboration, 16The Jefferson Lab Hall A Collaboration, 17The Jefferson Lab Hall A Collaboration, 18The Jefferson Lab Hall A Collaboration, 19The Jefferson Lab Hall A Collaboration, 20The Jefferson Lab Hall A Collaboration, 21The Jefferson Lab Hall A Collaboration, 22The Jefferson Lab Hall A Collaboration, 23The Jefferson Lab Hall A Collaboration, 24The Jefferson Lab Hall A Collaboration, 25The Jefferson Lab Hall A Collaboration, 26The Jefferson Lab Hall A Collaboration, 27The Jefferson Lab Hall A Collaboration, 28The Jefferson Lab Hall A Collaboration, 29The Jefferson Lab Hall A Collaboration, 30The Jefferson Lab Hall A Collaboration, 31The Jefferson Lab Hall A Collaboration, 32The Jefferson Lab Hall A Collaboration, 33The Jefferson Lab Hall A Collaboration, 34The Jefferson Lab Hall A Collaboration, 35The Jefferson Lab Hall A Collaboration, 36The Jefferson Lab Hall A Collaboration, 37The Jefferson Lab Hall A Collaboration, 38The Jefferson Lab Hall A Collaboration, 39The Jefferson Lab Hall A Collaboration, 40The Jefferson Lab Hall A Collaboration, 41The Jefferson Lab Hall A Collaboration, 42The Jefferson Lab Hall A Collaboration, 43The Jefferson Lab Hall A Collaboration, 44The Jefferson Lab Hall A Collaboration, 45The Jefferson Lab Hall A Collaboration, 46The Jefferson Lab Hall A Collaboration, 47The Jefferson Lab Hall A Collaboration, 48The Jefferson Lab Hall A Collaboration, 49The Jefferson Lab Hall A Collaboration, 50The Jefferson Lab Hall A Collaboration, 51The Jefferson Lab Hall A Collaboration, 52The Jefferson Lab Hall A Collaboration, 53The Jefferson Lab Hall A Collaboration, 54The Jefferson Lab Hall A Collaboration, 55The Jefferson Lab Hall A Collaboration, 56The Jefferson Lab Hall A Collaboration, 57The Jefferson Lab Hall A Collaboration, 58The Jefferson Lab Hall A Collaboration, 59The Jefferson Lab Hall A Collaboration, 60The Jefferson Lab Hall A Collaboration, 61The Jefferson Lab Hall A Collaboration, 62The Jefferson Lab Hall A Collaboration, 63The Jefferson Lab Hall A Collaboration, 64The Jefferson Lab Hall A Collaboration, 65The Jefferson Lab Hall A Collaboration, 66The Jefferson Lab Hall A Collaboration, 67The Jefferson Lab Hall A Collaboration, 68The Jefferson Lab Hall A Collaboration, 69The Jefferson Lab Hall A Collaboration, 70The Jefferson Lab Hall A Collaboration, 71The Jefferson Lab Hall A Collaboration, 72The 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Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson Lab using the exclusive photon electroproduction reaction (e p --> e p gamma). This paper gives a detailed account of the analysis which has led to the determination of the structure functions P_LL-P_TT/epsilon and P_LT, and the electric and magnetic generalized polarizabilities (GPs) alpha_E(Q^2) and beta_M(Q^2) at values of the four-momentum transfer squared Q^2= 0.92 and 1. Read More

2012May
Authors: J. L. Hewett, H. Weerts, R. Brock, J. N. Butler, B. C. K. Casey, J. Collar, A. de Gouvea, R. Essig, Y. Grossman, W. Haxton, J. A. Jaros, C. K. Jung, Z. T. Lu, K. Pitts, Z. Ligeti, J. R. Patterson, M. Ramsey-Musolf, J. L. Ritchie, A. Roodman, K. Scholberg, C. E. M. Wagner, G. P. Zeller, S. Aefsky, A. Afanasev, K. Agashe, C. Albright, J. Alonso, C. Ankenbrandt, M. Aoki, C. A. Arguelles, N. Arkani-Hamed, J. R. Armendariz, C. Armendariz-Picon, E. Arrieta Diaz, J. Asaadi, D. M. Asner, K. S. Babu, K. Bailey, O. Baker, B. Balantekin, B. Baller, M. Bass, B. Batell, J. Beacham, J. Behr, N. Berger, M. Bergevin, E. Berman, R. Bernstein, A. J. Bevan, M. Bishai, M. Blanke, S. Blessing, A. Blondel, T. Blum, G. Bock, A. Bodek, G. Bonvicini, F. Bossi, J. Boyce, R. Breedon, M. Breidenbach, S. J. Brice, R. A. Briere, S. Brodsky, C. Bromberg, A. Bross, T. E. Browder, D. A. Bryman, M. Buckley, R. Burnstein, E. Caden, P. Campana, R. Carlini, G. Carosi, C. Castromonte, R. Cenci, I. Chakaberia, M. C. Chen, C. H. Cheng, B. Choudhary, N. H. Christ, E. Christensen, M. E. Christy, T. E. Chupp, E. Church, D. B. Cline, T. E. Coan, P. Coloma, J. Comfort, L. Coney, J. Cooper, R. J. Cooper, R. Cowan, D. F. Cowen, D. Cronin-Hennessy, A. Datta, G. S. Davies, M. Demarteau, D. P. DeMille, A. Denig, R. Dermisek, A. Deshpande, M. S. Dewey, R. Dharmapalan, J. Dhooghe, M. R. Dietrich, M. Diwan, Z. Djurcic, S. Dobbs, M. Duraisamy, B. Dutta, H. Duyang, D. A. Dwyer, M. Eads, B. Echenard, S. R. Elliott, C. Escobar, J. Fajans, S. Farooq, C. Faroughy, J. E. Fast, B. Feinberg, J. Felde, G. Feldman, P. Fierlinger, P. Fileviez Perez, B. Filippone, P. Fisher, B. T. Flemming, K. T. Flood, R. Forty, M. J. Frank, A. Freyberger, A. Friedland, R. Gandhi, K. S. Ganezer, A. Garcia, F. G. Garcia, S. Gardner, L. Garrison, A. Gasparian, S. Geer, V. M. Gehman, T. Gershon, M. Gilchriese, C. Ginsberg, I. Gogoladze, M. Gonderinger, M. Goodman, H. Gould, M. Graham, P. W. Graham, R. Gran, J. Grange, G. Gratta, J. P. Green, H. Greenlee, R. C. Group, E. Guardincerri, V. Gudkov, R. Guenette, A. Haas, A. Hahn, T. Han, T. Handler, J. C. Hardy, R. Harnik, D. A. Harris, F. A. Harris, P. G. Harris, J. Hartnett, B. He, B. R. Heckel, K. M. Heeger, S. Henderson, D. Hertzog, R. Hill, E. A Hinds, D. G. Hitlin, R. J. Holt, N. Holtkamp, G. Horton-Smith, P. Huber, W. Huelsnitz, J. Imber, I. Irastorza, J. Jaeckel, I. Jaegle, C. James, A. Jawahery, D. Jensen, C. P. Jessop, B. Jones, H. Jostlein, T. Junk, A. L. Kagan, M. Kalita, Y. Kamyshkov, D. M. Kaplan, G. Karagiorgi, A. Karle, T. Katori, B. Kayser, R. Kephart, S. Kettell, Y. K. Kim, M. Kirby, K. Kirch, J. Klein, J. Kneller, A. Kobach, M. Kohl, J. Kopp, M. Kordosky, W. Korsch, I. Kourbanis, A. D. Krisch, P. Krizan, A. S. Kronfeld, S. Kulkarni, K. S. Kumar, Y. Kuno, T. Kutter, T. Lachenmaier, M. Lamm, J. Lancaster, M. Lancaster, C. Lane, K. Lang, P. Langacker, S. Lazarevic, T. Le, K. Lee, K. T. Lesko, Y. Li, M. Lindgren, A. Lindner, J. Link, D. Lissauer, L. S. Littenberg, B. Littlejohn, C. Y. Liu, W. Loinaz, W. Lorenzon, W. C. Louis, J. Lozier, L. Ludovici, L. Lueking, C. Lunardini, D. B. MacFarlane, P. A. N. Machado, P. B. Mackenzie, J. Maloney, W. J. Marciano, W. Marsh, M. Marshak, J. W. Martin, C. Mauger, K. S. McFarland, C. McGrew, G. McLaughlin, D. McKeen, R. McKeown, B. T. Meadows, R. Mehdiyev, D. Melconian, H. Merkel, M. Messier, J. P. Miller, G. Mills, U. K. Minamisono, S. R. Mishra, I. Mocioiu, S. Moed Sher, R. N. Mohapatra, B. Monreal, C. D. Moore, J. G. Morfin, J. Mousseau, L. A. Moustakas, G. Mueller, P. Mueller, M. Muether, H. P. Mumm, C. Munger, H. Murayama, P. Nath, O. Naviliat-Cuncin, J. K. Nelson, D. Neuffer, J. S. Nico, A. Norman, D. Nygren, Y. Obayashi, T. P. O'Connor, Y. Okada, J. Olsen, L. Orozco, J. L. Orrell, J. Osta, B. Pahlka, J. Paley, V. Papadimitriou, M. Papucci, S. Parke, R. H. Parker, Z. Parsa, K. Partyka, A. Patch, J. C. Pati, R. B. Patterson, Z. Pavlovic, G. Paz, G. N. Perdue, D. Perevalov, G. Perez, R. Petti, W. Pettus, A. Piepke, M. Pivovaroff, R. Plunkett, C. C. Polly, M. Pospelov, R. Povey, A. Prakesh, M. V. Purohit, S. Raby, J. L. Raaf, R. Rajendran, S. Rajendran, G. Rameika, R. Ramsey, A. Rashed, B. N. Ratcliff, B. Rebel, J. Redondo, P. Reimer, D. Reitzner, F. Ringer, A. Ringwald, S. Riordan, B. L. Roberts, D. A. Roberts, R. Robertson, F. Robicheaux, M. Rominsky, R. Roser, J. L. Rosner, C. Rott, P. Rubin, N. Saito, M. Sanchez, S. Sarkar, H. Schellman, B. Schmidt, M. Schmitt, D. W. Schmitz, J. Schneps, A. Schopper, P. Schuster, A. J. Schwartz, M. Schwarz, J. Seeman, Y. K. Semertzidis, K. K. Seth, Q. Shafi, P. Shanahan, R. Sharma, S. R. Sharpe, M. Shiozawa, V. Shiltsev, K. Sigurdson, P. Sikivie, J. Singh, D. Sivers, T. Skwarnicki, N. Smith, J. Sobczyk, H. Sobel, M. Soderberg, Y. H. Song, A. Soni, P. Souder, A. Sousa, J. Spitz, M. Stancari, G. C. Stavenga, J. H. Steffen, S. Stepanyan, D. Stoeckinger, S. Stone, J. Strait, M. Strassler, I. A. Sulai, R. Sundrum, R. Svoboda, B. Szczerbinska, A. Szelc, T. Takeuchi, P. Tanedo, S. Taneja, J. Tang, D. B. Tanner, R. Tayloe, I. Taylor, J. Thomas, C. Thorn, X. Tian, B. G. Tice, M. Tobar, N. Tolich, N. Toro, I. S. Towner, Y. Tsai, R. Tschirhart, C. D. Tunnell, M. Tzanov, A. Upadhye, J. Urheim, S. Vahsen, A. Vainshtein, E. Valencia, R. G. Van de Water, R. S. Van de Water, M. Velasco, J. Vogel, P. Vogel, W. Vogelsang, Y. W. Wah, D. Walker, N. Weiner, A. Weltman, R. Wendell, W. Wester, M. Wetstein, C. White, L. Whitehead, J. Whitmore, E. Widmann, G. Wiedemann, J. Wilkerson, G. Wilkinson, P. Wilson, R. J. Wilson, W. Winter, M. B. Wise, J. Wodin, S. Wojcicki, B. Wojtsekhowski, T. Wongjirad, E. Worcester, J. Wurtele, T. Xin, J. Xu, T. Yamanaka, Y. Yamazaki, I. Yavin, J. Yeck, M. Yeh, M. Yokoyama, J. Yoo, A. Young, E. Zimmerman, K. Zioutas, M. Zisman, J. Zupan, R. Zwaska

The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled particles, and nucleons, nuclei, and atoms. Read More

We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling $\alpha'$ to electrons. Such a particle $A'$ can be produced in electron-nucleus fixed-target scattering and then decay to an $e^+e^-$ pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an $A'\to e^+e^-$ reaction, and set an upper limit of $\alpha'/\alpha \simeq 10^{-6}$. Read More

In a recent article by Rodrigues et al. [1] eta photo-nuclear data taken by Browman et al. [2] in 1974 were refit as a means to extract the eta->gamma gamma decay width. Read More

Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. Read More

With the advent of new photon tagging facilities and novel experimental technologies it has become possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths from these measurements at forward angles is done by the Primakoff method, which requires theoretical treatment of all processes participating in these reactions at the same percent level. In this work we review the theoretical approach to meson photoproduction amplitudes in the electromagnetic and strong fields of nuclei at forward direction. Read More

A technique is presented for precision measurements of the area densities, density * T, of approximately 5% radiation length carbon and 208Pb targets used in an experiment at Jefferson Laboratory to measure the neutral pion radiative width. The precision obtained in the area density for the carbon target is +/- 0.050%, and that obtained for the lead target through an x-ray attenuation technique is +/- 0. Read More

We present a measurement of the spin-dependent cross sections for the \vec{^3He}(\vec{e},e')X} reaction in the quasielastic and resonance regions at four-momentum transfer 0.1 < Q^2< 0.9 GeV^2. Read More

In this report, we present the energy calibration of the Hall B bremsstrahlung tagging system at the Thomas Jefferson National Accelerator Facility. The calibration was performed using a magnetic pair spectrometer. The tagged photon energy spectrum was measured in coincidence with $e^+e^-$ pairs as a function of the pair spectrometer magnetic field. Read More

We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range 0.2 < Q^2 < 5.5 GeV^2. Read More

A pioneering experiment in Lambda hypernuclear spectroscopy, undertaken at the Thomas Jefferson National Accelerator Facility (Jlab), was recently reported. The experiment used the high- precision, continuous electron beam at Jlab, and a special arrangement of spectrometer magnets to measure the spectrum from {nat}C and 7Li targets using the (e,e' K+)reaction. The 12B hypernuclear spectrum was previously published. Read More

We have carried out an (e,e'p) experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function S(k,E) at high nucleon momenta k and large removal energies E. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable uncertainty from the lack of strength in the independent-particle region. This experiment confirms by direct measurement the correlated strength predicted by theory. Read More

A model calculation for the reactions $pp\to p\Lambda K^+$ and $pp\to N\Sigma K$ near their thresholds is presented. It is argued that the experimentally observed strong suppression of $\Sigma^0$ production compared to $\Lambda$ production at the same excess energy could be due to a destructive interference between the $\pi$ and $K$ exchange contributions in the reaction $pp\to p\Sigma^0 K^+$. Predictions for $pp\to p\Sigma^+ K^0$ and $pp\to n\Sigma^+ K^+$ are given. Read More

The influence of the nucleon-nucleon final state interaction (FSI) on properties of the meson production amplitude near threshold is discussed. For the nucleon-nucleon interaction a simple Yamaguchi potential as well as realistic potential models are considered. It is shown that FSI effects cannot be factorized from the production amplitude. Read More

1999Dec
Affiliations: 1Kharkov, FTI, 2Kharkov, FTI, 3Kharkov, FTI, 4Kharkov, FTI, 5Kharkov, FTI, 6Kharkov, FTI, 7Kentucky U., 8Kentucky U., 9Kentucky U., 10Kentucky U., 11Kentucky U., 12Jefferson Lab, 13Jefferson Lab, 14Jefferson Lab, 15Jefferson Lab, 16Hampton U.

As part of the spin physics program at Jefferson Laboratory (JLab), a M\o ller polarimeter was developed to measure the polarization of electron beam of energies 0.8 to 5.0 GeV. Read More

The reactions $pp\to p\Lambda K^+$ and $pp\to p\Sigma^0K^+$ are studied near their thresholds. The strangeness production process is described by the $\pi$- and $K$ exchange mechanisms. Effects from the final state interaction in the hyperon-nucleon system are taken into account rigorously. Read More