C. Keppel - HKS - JLab E05-115 and E01-001 - Collaborations

C. Keppel
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C. Keppel
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HKS - JLab E05-115 and E01-001 - Collaborations
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Nuclear Experiment (42)
 
High Energy Physics - Experiment (17)
 
High Energy Physics - Phenomenology (16)
 
Nuclear Theory (9)
 
Physics - Instrumentation and Detectors (5)

Publications Authored By C. Keppel

This workshop aimed at producing an optimized photon source concept with potential increase of scientific output at Jefferson Lab, and at refining the science for hadron physics experiments benefitting from such a high-intensity photon source. The workshop brought together the communities directly using such sources for photo-production experiments, or for conversion into $K_L$ beams. The combination of high precision calorimetry and high intensity photon sources greatly enhances scientific benefit to (deep) exclusive processes like wide-angle and time-like Compton scattering. Read More

The proton is composed of quarks and gluons, bound by the most elusive mechanism of strong interaction called confinement. In this work, the dynamics of quarks and gluons are investigated using deeply virtual Compton scattering (DVCS): produced by a multi-GeV electron, a highly virtual photon scatters off the proton which subsequently radiates a high energy photon. Similarly to holography, measuring not only the magnitude but also the phase of the DVCS amplitude allows to perform 3D images of the internal structure of the proton. Read More

2017Feb
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 Jefferson Lab Hall A Collaboration, 73The Jefferson Lab Hall A Collaboration, 74The Jefferson Lab Hall A Collaboration, 75The Jefferson Lab Hall A Collaboration, 76The Jefferson Lab Hall A Collaboration, 77The Jefferson Lab Hall A Collaboration, 78The Jefferson Lab Hall A Collaboration, 79The Jefferson Lab Hall A Collaboration, 80The Jefferson Lab Hall A Collaboration, 81The Jefferson Lab Hall A Collaboration, 82The Jefferson Lab Hall A Collaboration, 83The Jefferson Lab Hall A Collaboration, 84The Jefferson Lab Hall A Collaboration, 85The Jefferson Lab Hall A Collaboration, 86The Jefferson Lab Hall A Collaboration, 87The Jefferson Lab Hall A Collaboration, 88The Jefferson Lab Hall A Collaboration, 89The Jefferson Lab Hall A Collaboration, 90The Jefferson Lab Hall A Collaboration, 91The Jefferson Lab Hall A Collaboration, 92The Jefferson Lab Hall A Collaboration, 93The Jefferson Lab Hall A Collaboration, 94The Jefferson Lab Hall A Collaboration, 95The Jefferson Lab Hall A Collaboration, 96The Jefferson Lab Hall A Collaboration, 97The Jefferson Lab Hall A Collaboration, 98The Jefferson Lab Hall A Collaboration

We report the first longitudinal/transverse separation of the deeply virtual exclusive $\pi^0$ electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions $d\sigma_L/dt$, $d\sigma_T/dt$, $d\sigma_{LT}/dt$ and $d\sigma_{TT}/dt$ are extracted as a function of the momentum transfer to the recoil system at $Q^2$=1.75 GeV$^2$ and $x_B$=0. Read More

We present deeply virtual $\pi^0$ electroproduction cross-section measurements at $x_B$=0.36 and three different $Q^2$--values ranging from 1.5 to 2 GeV$^2$, obtained from experiment E07-007 that ran in the Hall A at Jefferson Lab. Read More

Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the quark dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available for the longitudinal structure function in particular. Here we present separated structure functions for hydrogen and deuterium at low four--momentum transfer squared, Q^2< 1 GeV^2, and compare these with parton distribution parameterizations and a k_T factorization approach. Read More

2015Nov
Affiliations: 1Jefferson Lab Hall A Collaboration, 2Jefferson Lab Hall A Collaboration, 3Jefferson Lab Hall A Collaboration, 4Jefferson Lab Hall A Collaboration, 5Jefferson Lab Hall A Collaboration, 6Jefferson Lab Hall A Collaboration, 7Jefferson Lab Hall A Collaboration, 8Jefferson Lab Hall A Collaboration, 9Jefferson Lab Hall A Collaboration, 10Jefferson Lab Hall A Collaboration, 11Jefferson Lab Hall A Collaboration, 12Jefferson Lab Hall A Collaboration, 13Jefferson Lab Hall A Collaboration, 14Jefferson Lab Hall A Collaboration, 15Jefferson Lab Hall A Collaboration, 16Jefferson Lab Hall A Collaboration, 17Jefferson Lab Hall A Collaboration, 18Jefferson Lab Hall A Collaboration, 19Jefferson Lab Hall A Collaboration, 20Jefferson Lab Hall A Collaboration, 21Jefferson Lab Hall A Collaboration, 22Jefferson Lab Hall A Collaboration, 23Jefferson Lab Hall A Collaboration

Report of the experimental activities in Hall A at Thomas Jefferson National Accelerator Facility during 2013. Read More

We present the first official release of the nCTEQ nuclear parton distribution functions with errors. The main addition to the previous nCTEQ PDFs is the introduction of PDF uncertainties based on the Hessian method. Another important addition is the inclusion of pion production data from RHIC that give us a handle on constraining the gluon PDF. Read More

We present the new nCTEQ15 set of nuclear parton distribution functions with uncertainties. This fit extends the CTEQ proton PDFs to include the nuclear dependence using data on nuclei all the way up to 208^Pb. The uncertainties are determined using the Hessian method with an optimal rescaling of the eigenvectors to accurately represent the uncertainties for the chosen tolerance criteria. Read More

We have determined the structure function ratio $R^d_{\rm EMC}=F_2^d/(F_2^n+F_2^p)$ from recently published $F_2^n/F_2^d$ data taken by the BONuS experiment using CLAS at Jefferson Lab. This ratio deviates from unity, with a slope $dR_{\rm EMC}^{d}/dx= -0.10\pm 0. Read More

We present final results on the photon electroproduction ($\vec{e}p\rightarrow ep\gamma$) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed resulting in photon electroproduction cross sections at new kinematic settings, for a total of 588 experimental bins. Read More

New results are reported from a measurement of $\pi^0$ electroproduction near threshold using the $p(e,e^{\prime} p)\pi^0$ reaction. The experiment was designed to determine precisely the energy dependence of $s-$ and $p-$wave electromagnetic multipoles as a stringent test of the predictions of Chiral Perturbation Theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. Read More

Using data from the recent BONuS experiment at Jefferson Lab, which utilized a novel spectator tagging technique to extract the inclusive electron-free neutron scattering cross section, we obtain the first direct observation of quark-hadron duality in the neutron F_2 structure function. The data are used to reconstruct the lowest few (N=2, 4 and 6) moments of F_2 in the three prominent nucleon resonance regions, as well as the moments integrated over the entire resonance region. Comparison with moments computed from global parametrizations of parton distribution functions suggest that quark--hadron duality holds locally for the neutron in the second and third resonance regions down to Q^2 ~ 1 GeV^2, with violations possibly up to 20% observed in the first resonance region. Read More

Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in $\pi^-$ and $\pi^+$ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form factor from electroproduction data. Read More

2014Nov
Authors: MOLLER Collaboration, J. Benesch, P. Brindza, R. D. Carlini, J-P. Chen, E. Chudakov, S. Covrig, M. M. Dalton, A. Deur, D. Gaskell, A. Gavalya, J. Gomez, D. W. Higinbotham, C. Keppel, D. Meekins, R. Michaels, B. Moffit, Y. Roblin, R. Suleiman, R. Wines, B. Wojtsekhowski, G. Cates, D. Crabb, D. Day, K. Gnanvo, D. Keller, N. Liyanage, V. V. Nelyubin, H. Nguyen, B. Norum, K. Paschke, V. Sulkosky, J. Zhang, X. Zheng, J. Birchall, P. Blunden, M. T. W. Gericke, W. R. Falk, L. Lee, J. Mammei, S. A. Page, W. T. H. van Oers, K. Dehmelt, A. Deshpande, N. Feege, T. K. Hemmick, K. S. Kumar, T. Kutz, R. Miskimen, M. J. Ramsey-Musolf, S. Riordan, N. Hirlinger Saylor, J. Bessuille, E. Ihloff, J. Kelsey, S. Kowalski, R. Silwal, G. De Cataldo, R. De Leo, D. Di Bari, L. Lagamba, E. NappiV. Bellini, F. Mammoliti, F. Noto, M. L. Sperduto, C. M. Sutera, P. Cole, T. A. Forest, M. Khandekar, D. McNulty, K. Aulenbacher, S. Baunack, F. Maas, V. Tioukine, R. Gilman, K. Myers, R. Ransome, A. Tadepalli, R. Beniniwattha, R. Holmes, P. Souder, D. S. Armstrong, T. D. Averett, W. Deconinck, W. Duvall, A. Lee, M. L. Pitt, J. A. Dunne, D. Dutta, L. El Fassi, F. De Persio, F. Meddi, G. M. Urciuoli, E. Cisbani, C. Fanelli, F. Garibaldi, K. Johnston, N. Simicevic, S. Wells, P. M. King, J. Roche, J. Arrington, P. E. Reimer, G. Franklin, B. Quinn, A. Ahmidouch, S. Danagoulian, O. Glamazdin, R. Pomatsalyuk, R. Mammei, J. W. Martin, T. Holmstrom, J. Erler, Yu. G. Kolomensky, J. Napolitano, K. A. Aniol, W. D. Ramsay, E. Korkmaz, D. T. Spayde, F. Benmokhtar, A. Del Dotto, R. Perrino, S. Barkanova, A. Aleksejevs, J. Singh

The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Lepton Electroweak Reaction) experiment at the 12 GeV upgraded Jefferson Lab are presented. A highlight of the Fundamental Symmetries subfield of the 2007 NSAC Long Range Plan was the SLAC E158 measurement of the parity-violating asymmetry $A_{PV}$ in polarized electron-electron (M{\o}ller) scattering. The proposed MOLLER experiment will improve on this result by a factor of five, yielding the most precise measurement of the weak mixing angle at low or high energy anticipated over the next decade. Read More

The interpretation of the signals detected by high precision experiments aimed at measuring neutrino oscillations requires an accurate description of the neutrino-nucleus cross sections. One of the key element of the analysis is the treatment of nuclear effects, which is one of the main sources of systematics for accelerator based experiments such as the Long Baseline Neutrino Experiment (LBNE). A considerable effort is currently being made to develop theoretical models capable of providing a fully quantitative description of the neutrino-nucleus cross sections in the kinematical regime relevant to LBNE. 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 - 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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

2014Apr
Affiliations: 1The Jefferson Lab Fpi Collaboration, 2The Jefferson Lab Fpi Collaboration, 3The Jefferson Lab Fpi Collaboration, 4The Jefferson Lab Fpi Collaboration, 5The Jefferson Lab Fpi Collaboration, 6The Jefferson Lab Fpi Collaboration, 7The Jefferson Lab Fpi Collaboration, 8The Jefferson Lab Fpi Collaboration, 9The Jefferson Lab Fpi Collaboration, 10The Jefferson Lab Fpi Collaboration, 11The Jefferson Lab Fpi Collaboration, 12The Jefferson Lab Fpi Collaboration, 13The Jefferson Lab Fpi Collaboration, 14The Jefferson Lab Fpi Collaboration, 15The Jefferson Lab Fpi Collaboration, 16The Jefferson Lab Fpi Collaboration, 17The Jefferson Lab Fpi Collaboration, 18The Jefferson Lab Fpi Collaboration, 19The Jefferson Lab Fpi Collaboration, 20The Jefferson Lab Fpi Collaboration, 21The Jefferson Lab Fpi Collaboration, 22The Jefferson Lab Fpi Collaboration, 23The Jefferson Lab Fpi Collaboration, 24The Jefferson Lab Fpi Collaboration, 25The Jefferson Lab Fpi Collaboration, 26The Jefferson Lab Fpi Collaboration, 27The Jefferson Lab Fpi Collaboration, 28The Jefferson Lab Fpi Collaboration, 29The Jefferson Lab Fpi Collaboration, 30The Jefferson Lab Fpi Collaboration, 31The Jefferson Lab Fpi Collaboration, 32The Jefferson Lab Fpi Collaboration, 33The Jefferson Lab Fpi Collaboration, 34The Jefferson Lab Fpi Collaboration, 35The Jefferson Lab Fpi Collaboration, 36The Jefferson Lab Fpi Collaboration, 37The Jefferson Lab Fpi Collaboration, 38The Jefferson Lab Fpi Collaboration, 39The Jefferson Lab Fpi Collaboration, 40The Jefferson Lab Fpi Collaboration, 41The Jefferson Lab Fpi Collaboration, 42The Jefferson Lab Fpi Collaboration, 43The Jefferson Lab Fpi Collaboration, 44The Jefferson Lab Fpi Collaboration, 45The Jefferson Lab Fpi Collaboration, 46The Jefferson Lab Fpi Collaboration, 47The Jefferson Lab Fpi Collaboration, 48The Jefferson Lab Fpi Collaboration, 49The Jefferson Lab Fpi Collaboration, 50The Jefferson Lab Fpi Collaboration, 51The Jefferson Lab Fpi Collaboration, 52The Jefferson Lab Fpi Collaboration, 53The Jefferson Lab Fpi Collaboration, 54The Jefferson Lab Fpi Collaboration, 55The Jefferson Lab Fpi Collaboration, 56The Jefferson Lab Fpi Collaboration, 57The Jefferson Lab Fpi Collaboration, 58The Jefferson Lab Fpi Collaboration, 59The Jefferson Lab Fpi Collaboration, 60The Jefferson Lab Fpi Collaboration, 61The Jefferson Lab Fpi Collaboration, 62The Jefferson Lab Fpi Collaboration, 63The Jefferson Lab Fpi Collaboration, 64The Jefferson Lab Fpi Collaboration, 65The Jefferson Lab Fpi Collaboration, 66The Jefferson Lab Fpi Collaboration, 67The Jefferson Lab Fpi Collaboration, 68The Jefferson Lab Fpi Collaboration, 69The Jefferson Lab Fpi Collaboration, 70The Jefferson Lab Fpi Collaboration, 71The Jefferson Lab Fpi Collaboration, 72The Jefferson Lab Fpi Collaboration, 73The Jefferson Lab Fpi Collaboration, 74The Jefferson Lab Fpi Collaboration, 75The Jefferson Lab Fpi Collaboration, 76The Jefferson Lab Fpi Collaboration, 77The Jefferson Lab Fpi Collaboration, 78The Jefferson Lab Fpi Collaboration, 79The Jefferson Lab Fpi Collaboration, 80The Jefferson Lab Fpi Collaboration, 81The Jefferson Lab Fpi Collaboration, 82The Jefferson Lab Fpi Collaboration, 83The Jefferson Lab Fpi Collaboration, 84The Jefferson Lab Fpi Collaboration, 85The Jefferson Lab Fpi Collaboration, 86The Jefferson Lab Fpi Collaboration, 87The Jefferson Lab Fpi Collaboration, 88The Jefferson Lab Fpi Collaboration

The study of exclusive $\pi^{\pm}$ electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio $R_L=\sigma_L^{\pi^-}/\sigma_L^{\pi^+}$ is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of $R_T=\sigma_T^{\pi^-}/\sigma_T^{\pi^+}$ from unity at small $-t$, to 1/4 at large $-t$, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Read More

2014Feb
Authors: S. Tkachenko1, N. Baillie2, S. E. Kuhn3, J. Zhang4, J. Arrington5, P. Bosted6, S. Bültmann7, M. E. Christy8, D. Dutta9, R. Ent10, H. Fenker11, K. A. Griffioen12, M. Ispiryan13, N. Kalantarians14, C. E. Keppel15, W. Melnitchouk16, V. Tvaskis17, K. P. Adhikari18, M. Aghasyan19, M. J. Amaryan20, S. Anefalos Pereira21, H. Avakian22, J. Ball23, N. A. Baltzell24, M. Battaglieri25, I. Bedlinskiy26, A. S. Biselli27, W. J. Briscoe28, W. K. Brooks29, V. D. Burkert30, D. S. Carman31, A. Celentano32, S. Chandavar33, G. Charles34, P. L. Cole35, M. Contalbrigo36, O. Cortes37, V. Crede38, A. D'Angelo39, N. Dashyan40, R. De Vita41, E. De Sanctis42, A. Deur43, C. Djalali44, G. E. Dodge45, D. Doughty46, R. Dupre47, H. Egiyan48, A. El Alaoui49, L. El Fassi50, L. Elouadrhiri51, P. Eugenio52, G. Fedotov53, J. A. Fleming54, B. Garillon55, N. Gevorgyan56, Y. Ghandilyan57, G. P. Gilfoyle58, K. L. Giovanetti59, F. X. Girod60, J. T. Goetz61, E. Golovatch62, R. W. Gothe63, M. Guidal64, L. Guo65, K. Hafidi66, H. Hakobyan67, C. Hanretty68, N. Harrison69, M. Hattawy70, K. Hicks71, D. Ho72, M. Holtrop73, C . E. Hyde74, Y. Ilieva75, D. G. Ireland76, B. S. Ishkhanov77, H. S. Jo78, D. Keller79, M. Khandaker80, A. Kim81, W. Kim82, P. M. King83, A. Klein84, F. J. Klein85, S. Koirala86, V. Kubarovsky87, S. V. Kuleshov88, P. Lenisa89, S. Lewis90, K. Livingston91, H. Lu92, M. MacCormick93, I. J. D. MacGregor94, N. Markov95, M. Mayer96, B. McKinnon97, T. Mineeva98, M. Mirazita99, V. Mokeev100, R. A. Montgomery101, H. Moutarde102, C. Munoz Camacho103, P. Nadel-Turonski104, S. Niccolai105, G. Niculescu106, I. Niculescu107, M. Osipenko108, L. L. Pappalardo109, R. Paremuzyan110, K. Park111, E. Pasyuk112, J. J. Phillips113, S. Pisano114, O. Pogorelko115, S. Pozdniakov116, J. W. Price117, S. Procureur118, D. Protopopescu119, A. J . R. Puckett120, D. Rimal121, M. Ripani122, A. Rizzo123, G. Rosner124, P. Rossi125, P. Roy126, F. Sabatié127, D. Schott128, R. A. Schumacher129, E. Seder130, I. Senderovich131, Y. G. Sharabian132, A. Simonyan133, G. D. Smith134, D. I. Sober135, D. Sokhan136, S. Stepanyan137, S. S. Stepanyan138, S. Strauch139, W. Tang140, M. Ungaro141, A. V. Vlassov142, H. Voskanyan143, E. Voutier144, N. K. Walford145, D. Watts146, X. Wei147, L. B. Weinstein148, M. H. Wood149, L. Zana150, I. Zonta151
Affiliations: 1The CLAS collaboration, 2The CLAS collaboration, 3The CLAS collaboration, 4The CLAS collaboration, 5The CLAS collaboration, 6The CLAS collaboration, 7The CLAS collaboration, 8The CLAS collaboration, 9The CLAS collaboration, 10The CLAS collaboration, 11The CLAS collaboration, 12The CLAS collaboration, 13The CLAS collaboration, 14The CLAS collaboration, 15The CLAS collaboration, 16The CLAS collaboration, 17The CLAS collaboration, 18The CLAS collaboration, 19The CLAS collaboration, 20The CLAS collaboration, 21The CLAS collaboration, 22The CLAS collaboration, 23The CLAS collaboration, 24The CLAS collaboration, 25The CLAS collaboration, 26The CLAS collaboration, 27The CLAS collaboration, 28The CLAS collaboration, 29The CLAS collaboration, 30The CLAS collaboration, 31The CLAS collaboration, 32The CLAS collaboration, 33The CLAS collaboration, 34The CLAS collaboration, 35The CLAS collaboration, 36The CLAS collaboration, 37The CLAS collaboration, 38The CLAS collaboration, 39The CLAS collaboration, 40The CLAS collaboration, 41The CLAS collaboration, 42The CLAS collaboration, 43The CLAS collaboration, 44The CLAS collaboration, 45The CLAS collaboration, 46The CLAS collaboration, 47The CLAS collaboration, 48The CLAS collaboration, 49The CLAS collaboration, 50The CLAS collaboration, 51The CLAS collaboration, 52The CLAS collaboration, 53The CLAS collaboration, 54The CLAS collaboration, 55The CLAS collaboration, 56The CLAS collaboration, 57The CLAS collaboration, 58The CLAS collaboration, 59The CLAS collaboration, 60The CLAS collaboration, 61The CLAS collaboration, 62The CLAS collaboration, 63The CLAS collaboration, 64The CLAS collaboration, 65The CLAS collaboration, 66The CLAS collaboration, 67The CLAS collaboration, 68The CLAS collaboration, 69The CLAS collaboration, 70The CLAS collaboration, 71The CLAS collaboration, 72The CLAS collaboration, 73The CLAS collaboration, 74The CLAS collaboration, 75The CLAS collaboration, 76The CLAS collaboration, 77The CLAS collaboration, 78The CLAS collaboration, 79The CLAS collaboration, 80The CLAS collaboration, 81The CLAS collaboration, 82The CLAS collaboration, 83The CLAS collaboration, 84The CLAS collaboration, 85The CLAS collaboration, 86The CLAS collaboration, 87The CLAS collaboration, 88The CLAS collaboration, 89The CLAS collaboration, 90The CLAS collaboration, 91The CLAS collaboration, 92The CLAS collaboration, 93The CLAS collaboration, 94The CLAS collaboration, 95The CLAS collaboration, 96The CLAS collaboration, 97The CLAS collaboration, 98The CLAS collaboration, 99The CLAS collaboration, 100The CLAS collaboration, 101The CLAS collaboration, 102The CLAS collaboration, 103The CLAS collaboration, 104The CLAS collaboration, 105The CLAS collaboration, 106The CLAS collaboration, 107The CLAS collaboration, 108The CLAS collaboration, 109The CLAS collaboration, 110The CLAS collaboration, 111The CLAS collaboration, 112The CLAS collaboration, 113The CLAS collaboration, 114The CLAS collaboration, 115The CLAS collaboration, 116The CLAS collaboration, 117The CLAS collaboration, 118The CLAS collaboration, 119The CLAS collaboration, 120The CLAS collaboration, 121The CLAS collaboration, 122The CLAS collaboration, 123The CLAS collaboration, 124The CLAS collaboration, 125The CLAS collaboration, 126The CLAS collaboration, 127The CLAS collaboration, 128The CLAS collaboration, 129The CLAS collaboration, 130The CLAS collaboration, 131The CLAS collaboration, 132The CLAS collaboration, 133The CLAS collaboration, 134The CLAS collaboration, 135The CLAS collaboration, 136The CLAS collaboration, 137The CLAS collaboration, 138The CLAS collaboration, 139The CLAS collaboration, 140The CLAS collaboration, 141The CLAS collaboration, 142The CLAS collaboration, 143The CLAS collaboration, 144The CLAS collaboration, 145The CLAS collaboration, 146The CLAS collaboration, 147The CLAS collaboration, 148The CLAS collaboration, 149The CLAS collaboration, 150The CLAS collaboration, 151The CLAS collaboration

Much less is known about neutron structure than that of the proton due to the absence of free neutron targets. Neutron information is usually extracted from data on nuclear targets such as deuterium, requiring corrections for nuclear binding and nucleon off-shell effects. These corrections are model dependent and have significant uncertainties, especially for large values of the Bjorken scaling variable x. Read More

2013May

The MINERvA experiment is designed to perform precision studies of neutrino-nucleus scattering using $\nu_\mu$ and ${\bar\nu}_\mu$ neutrinos incident at 1-20 GeV in the NuMI beam at Fermilab. This article presents a detailed description of the \minerva detector and describes the {\em ex situ} and {\em in situ} techniques employed to characterize the detector and monitor its performance. The detector is comprised of a finely-segmented scintillator-based inner tracking region surrounded by electromagnetic and hadronic sampling calorimetry. Read More

2013May
Authors: The MINERvA collaboration, L. Fields, J. Chvojka, L. Aliaga, O. Altinok, B. Baldin, A. Baumbaugh, A. Bodek, D. Boehnlein, S. Boyd, R. Bradford, W. K. Brooks, H. Budd, A. Butkevich, D. A. Martinez Caicedo, C. M. Castromonte, M. E. Christy, H. Chung, M. Clark, H. da Motta, D. S. Damiani, I. Danko, M. Datta, M. Day, R. DeMaat, J. Devan, E. Draeger, S. A. Dytman, G. A. Díaz, B. Eberly, D. A. Edmondson, J. Felix, T. Fitzpatrick, G. A. Fiorentini, A. M. Gago, H. Gallagher, C. A. George, J. A. Gielata, C. Gingu, B. Gobbi, R. Gran, N. Grossman, J. Hanson, D. A. Harris, J. Heaton, A. Higuera, I. J. Howley, K. Hurtado, M. Jerkins, T. Kafka, J. Kaisen, M. O. Kanter, C. E. Keppel, J. Kilmer, M. Kordosky, A. H. Krajeski, S. A. Kulagin, T. Le, H. Lee, A. G. Leister, G. Locke, G. Maggi, E. Maher, S. Manly, W. A. Mann, C. M. Marshall, K. S. McFarland, C. L. McGivern, A. M. McGowan, A. Mislivec, J. G. Morfín, J. Mousseau, D. Naples, J. K. Nelson, G. Niculescu, I. Niculescu, N. Ochoa, C. D. O'Connor, J. Olsen, B. Osmanov, J. Osta, J. L. Palomino, V. Paolone, J. Park, C. E. Patrick, G. N. Perdue, C. Peña, L. Rakotondravohitra, R. D. Ransome, H. Ray, L. Ren, P. A. Rodrigues, C. Rude, K. E. Sassin, H. Schellman, D. W. Schmitz, R. M. Schneider, E. C. Schulte, C. Simon, F. D. Snider, M. C. Snyder, J. T. Sobczyk, C. J. Solano Salinas, N. Tagg, W. Tan, B. G. Tice, G. Tzanakos, J. P. Velásquez, J. Walding, T. Walton, J. Wolcott, B. A. Wolthuis, N. Woodward, G. Zavala, H. B. Zeng, D. Zhang, L. Y. Zhu, B. P. Ziemer

We have isolated muon anti-neutrino charged-current quasi-elastic interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross-section, d{\sigma}/dQ^2, and compare to several theoretical models of quasi-elastic scattering. Good agreement is obtained with a model where the nucleon axial mass, M_A, is set to 0. Read More

2013May
Authors: The MINERvA collaboration, G. A. Fiorentini, D. W. Schmitz, P. A. Rodrigues, L. Aliaga, O. Altinok, B. Baldin, A. Baumbaugh, A. Bodek, D. Boehnlein, S. Boyd, R. Bradford, W. K. Brooks, H. Budd, A. Butkevich, D. A. Martinez Caicedo, C. M. Castromonte, M. E. Christy, H. Chung, J. Chvojka, M. Clark, H. da Motta, D. S. Damiani, I. Danko, M. Datta, M. Day, R. DeMaat, J. Devan, E. Draeger, S. A. Dytman, G. A. Díaz, B. Eberly, D. A. Edmondson, J. Felix, T. Fitzpatrick, L. Fields, A. M. Gago, H. Gallagher, C. A. George, J. A. Gielata, C. Gingu, B. Gobbi, R. Gran, N. Grossman, J. Hanson, D. A. Harris, J. Heaton, A. Higuera, I. J. Howley, K. Hurtado, M. Jerkins, T. Kafka, J. Kaisen, M. O. Kanter, C. E. Keppel, J. Kilmer, M. Kordosky, A. H. Krajeski, S. A. Kulagin, T. Le, H. Lee, A. G. Leister, G. Locke, G. Maggi, E. Maher, S. Manly, W. A. Mann, C. M. Marshall, K. S. McFarland, C. L. McGivern, A. M. McGowan, A. Mislivec, J. G. Morfń, J. Mousseau, D. Naples, J. K. Nelson, G. Niculescu, I. Niculescu, N. Ochoa, C. D. O'Connor, J. Olsen, B. Osmanov, J. Osta, J. L. Palomino, V. Paolone, J. Park, C. E. Patrick, G. N. Perdue, C. Peña, L. Rakotondravohitra, R. D. Ransome, H. Ray, L. Ren, C. Rude, K. E. Sassin, H. Schellman, R. M. Schneider, E. C. Schulte, C. Simon, F. D. Snider, M. C. Snyder, J. T. Sobczyk, C. J. Solano Salinas, N. Tagg, W. Tan, B. G. Tice, G. Tzanakos, J. P. Velásquez, J. Walding, T. Walton, J. Wolcott, B. A. Wolthuis, N. Woodward, G. Zavala, H. B. Zeng, D. Zhang, L. Y. Zhu, B. P. Ziemer

We report a study of muon neutrino charged-current quasi-elastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a {\mu}^- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross-section, d{\sigma}/dQ^2, and study the low energy particle content of the final state. Read More

We present an extraction of the lowest three moments of the proton longitudinal structure function F_L from world data between Q^2 = 0.75 and 45 (GeV/c)^2. The availability of new F_L data at low Bjorken x from HERA and at large x from Jefferson Lab allows the first determination of these moments over a large Q^2 range, relatively free from uncertainties associated with extrapolations into unmeasured regions. 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

2012Jun

We study the impact of the nuclear dependence of R=\sigma_L/\sigma_T on the extraction of the F_2^A/F_2^D and F_1^A/F_1^D structure function ratios from the data on the \sigma^A/\sigma^D cross section ratios. Guided by indications of the nuclear dependence of R from the world data, we examine selected sets of EMC, BCDMS, NMC and SLAC data and find that F_1^A/F_1^D < \sigma^A/\sigma^D \leq F_2^A/F_2^D. In particular, we observe that the nuclear enhancement (antishadowing) for F_1^A/F_1^D in the interval 0. Read More

The electromagnetic calorimeters of the various magnetic spectrometers in Hall C at Jefferson Lab are presented. For the existing HMS and SOS spectrometers design considerations, relevant construction information, and comparisons of simulated and experimental results are included. The energy resolution of the HMS and SOS calorimeters is better than $\sigma/E \sim 6%/\sqrt E $, and pion/electron ($\pi/e$) separation of about 100:1 has been achieved in energy range 1 -- 5 GeV. Read More

We propose a new precision measurement of parity-violating electron scattering on the proton at very low Q^2 and forward angles to challenge predictions of the Standard Model and search for new physics. A unique opportunity exists to carry out the first precision measurement of the proton's weak charge, $Q_W =1 - 4\sin^2\theta_W$. A 2200 hour measurement of the parity violating asymmetry in elastic ep scattering at Q^2=0. Read More

The neutrino deep inelastic scattering (DIS) data is very interesting for global analyses of proton and nuclear parton distribution functions (PDFs) since they provide crucial information on the strange quark distribution in the proton and allow for a better flavor decompositon of the PDFs. In order to use neutrino DIS data in a global analysis of proton PDFs nuclear effects need to be understood. We study these effects with the help of nuclear PDFs extracted from global analyses of charged-lepton DIS, Drell-Yan and neutrino DIS data at next-to-leading order in QCD. Read More

2011Oct
Authors: N. Baillie, S. Tkachenko, J. Zhang, P. Bosted, S. Bultmann, M. E. Christy, H. Fenker, K. A. Griffioen, C. E. Keppel, S. E. Kuhn, W. Melnitchouk, V. Tvaskis, K. P. Adhikari, D. Adikaram, M. Aghasyan, M. J. Amaryan, M. Anghinolfini, J. Arrington, H. Avakian, H. Baghdasaryan, M. Battaglieri, A. S. Biselli, 5 D. Branford, W. J. Briscoe, W. K. Brooks, V. D. Burkert, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, P. L. Cole, M. Contalbrigo, V. Crede, A. D'Angelo, A. Daniel, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, B. Dey, C. Djalali, G. Dodge, J. Domingo, D. Doughty, R. Dupre, D. Dutta, R. Ent, H. Egiyan, A. El Alaoui, L. El Fassi, L. Elouadrhiri, P. Eugenio, G. Fedotov, S. Fegan, A. Fradi, M. Y. Gabrielyan, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, W. Gohn, E. Golovatch, R. W. Gothe, L. Graham, B. Guegan, M. Guidal, N. Guler, L. Guo, K. Hafidi, D. Heddle, K. Hicks, M. Holtrop, E. Hungerford, C. E. Hyde, Y. Ilieva, D. G. Ireland, M. Ispiryan, E. L. Isupov, S. S. Jawalkar, H. S. Jo, N. Kalantarians, M. Khandaker, P. Khetarpal, A. Kim, W. Kim, P. M. King, A. Klein, F. J. Klein, A. Klimenko, V. Kubarovsky, S. V. Kuleshov, N. D. Kvaltine, K. Livingston, H. Y. Lu, I . J . D. MacGregor, Y. Mao, N. Markov, B. McKinnon, T. Mineeva, B. Morrison, H. Moutarde, E. Munevar, P. Nadel-Turonski, A. Ni, S. Niccolai, I. Niculescu, G. Niculescu, M. Osipenko, A. I. Ostrovidov, L. Pappalardo, K. Park, S. Park, E. Pasyuk, S. Anefalos Pereira, S. Pisano, S. Pozdniakov, J. W. Price, S. Procureur, Y. Prok, D. Protopopescu, B. A. Raue, G. Ricco, D. Rimal, M. Ripani, G. Rosner, P. Rossi, F. Sabatie, M. S. Saini, C. Salgado, D. Schott, R. A. Schumacher, E. Seder, Y. G. Sharabian, D. I. Sober, D. Sokhan, S. Stepanyan, S. S. Stepanyan, P. Stoler, S. Strauch, M. Taiuti, W. Tang, M. Ungaro, M. F. Vineyard, E. Voutier, D. P. Watts, L. B. Weinstein, D. P. Weygand, M. H. Wood, L. Zana, B. Zhao

We report on the first measurement of the F2 structure function of the neutron from semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to < 100 MeV and their angles to < 100 degrees relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F2n data collected cover the nucleon resonance and deep-inelastic regions over a wide range of Bjorken x for 0. Read More

We present new data for the polarization observables of the final state proton in the $^{1}H(\vec{\gamma},\vec{p})\pi^{0}$ reaction. These data can be used to test predictions based on hadron helicity conservation (HHC) and perturbative QCD (pQCD). These data have both small statistical and systematic uncertainties, and were obtained with beam energies between 1. Read More

A large set of cross sections for semi-inclusive electroproduction of charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4 GeV$^2$ and range in four-momentum transfer squared $2 < Q^2 < 4$ (GeV/c)$^2$, and cover a range in the Bjorken scaling variable 0.2 < x < 0. Read More

We critically examine uncertainties in parton distribution functions (PDFs) at large x arising from nuclear effects in deuterium F2 structure function data. Within a global PDF analysis, we assess the impact on the PDFs from uncertainties in the deuteron wave function at short distances and nucleon off-shell effects, the use of relativistic kinematics, as well as the use of less a restrictive parametrization of the d/u ratio. We find that in particular the d-quark and gluon PDFs vary significantly with the choice of nuclear model. Read More

We present a summary of a recent workshop held at Duke University on Partonic Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon Interactions. The transverse momentum dependent parton distribution functions (TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation functions, were discussed extensively at the Duke workshop. In this paper, we summarize first the theoretical issues concerning the study of partonic structure of hadrons at a future electron-ion collider (EIC) with emphasis on the TMDs. Read More

We perform a global chi^2-analysis of nuclear parton distribution functions using data from charged current neutrino-nucleus deep-inelastic scattering (DIS), charged-lepton-nucleus DIS, and the Drell-Yan (DY) process. We show that the nuclear corrections in nu-A DIS are not compatible with the predictions derived from l^+A DIS and DY data. We quantify this result using a hypothesis-testing criterion based on the chi^2 distribution which we apply to the total chi^2 as well as to the chi^2 of the individual data sets. Read More

2010Dec

Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, $G_{E}/G_{M}$, obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange (TPEX) contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic $H(\vec{e},e'\vec{p})$ reaction for three different beam energies at a fixed squared momentum transfer $Q^2 = 2. Read More

We present new data on electron scattering from a range of nuclei taken in Hall C at Jefferson Lab. For heavy nuclei, we observe a rapid falloff in the cross section for $x>1$, which is sensitive to short range contributions to the nuclear wave-function, and in deep inelastic scattering corresponds to probing extremely high momentum quarks. This result agrees with higher energy muon scattering measurements, but is in sharp contrast to neutrino scattering measurements which suggested a dramatic enhancement in the distribution of the `super-fast' quarks probed at x>1. Read More

2010May

Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this letter, we report new measurements of the proton electromagnetic form factor ratio using the recoil polarization method, at momentum transfers Q2=5.2, 6. Read More

We report results of a new global next-to-leading order fit of parton distribution functions in which cuts on W and Q are relaxed, thereby including more data at high values of x. Effects of target mass corrections (TMCs), higher twist contributions, and nuclear corrections for deuterium data are significant in the large-x region. The leading twist parton distributions are found to be stable to TMC model variations as long as higher twist contributions are also included. Read More

We apply a recently developed technique to extract for the first time the neutron F_2^n structure function from inclusive proton and deuteron data in the nucleon resonance region, and test the validity of quark-hadron duality in the neutron. We establish the accuracy of duality in the low-lying neutron resonance regions over a range of Q^2, and compare with the corresponding results on the proton and with theoretical expectations. The confirmation of duality in both the neutron and proton opens the possibility of using resonance region data to constrain parton distributions at large x. Read More

We perform a \chi^2-analysis of Nuclear Parton Distribution Functions (NPDFs) using neutral current charged-lepton Deeply Inelastic Scattering (DIS) and Drell-Yan data for several nuclear targets. The nuclear A dependence of the NPDFs is extracted in a next-to-leading order fit. We compare the nuclear corrections factors F2(Fe)/F2(D) for this charged-lepton data with other results from the literature. Read More