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

P. Solvignon,1 N. Liyanage,2 J.-P. Chen,3 Seonho Choi,4 K. Slifer,1 K. Aniol,5 T. Averett,6 W. Boeglin,7 A. Camsonne,3 G. D. Cates,2 C. C. Chang,8 E. Chudakov,3 B. Craver,2 F. Cusanno,9 A. Deur,3 D. Dutta,10 R. Ent,3 R. Feuerbach,3 S. Frullani,9 H. Gao,10 F. Garibaldi,9 R. Gilman,11 C. Glashausser,11 V. Gorbenko,12 O. Hansen,3 D. W. Higinbotham,3 H. Ibrahim,13 X. Jiang,11 M. Jones,3 A. Kelleher,6 J. Kelly,8,* C. Keppel,3 W. Kim,14 W. Korsch,15 K. Kramer,6 G. Kumbartzki,11 J. J. LeRose,3 R. Lindgren,2 B. Ma,16 D. J. Margaziotis,5 P. Markowitz,7 K. McCormick,11 Z.-E. Meziani,17 R. Michaels,3 B. Moffit,6 P. Monaghan,16 C. Munoz Camacho,18 K. Paschke,2 B. Reitz,3 A. Saha,3,* R. Shneor,19 J. Singh,2 V. Sulkosky,6 A. Tobias,2 G. M. Urciuoli,20 K. Wang,2 K. Wijesooriya,10 B. Wojtsekhowski,3 S. Woo,14 J.-C. Yang,21 X. Zheng,2 and L. Zhu16 (Jefferson Lab E01-012 Collaboration) 1University of New Hampshire, Durham, New Hampshire 03824, USA 2University of Virginia, Charlottesville, Virginia 22904, USA 3Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA 4Seoul National University, Seoul 151-747, Korea 5California State University, Los Angeles, Los Angeles, California 90032, USA 6College of William and Mary, Williamsburg, Virginia 23187, USA 7Florida International University, Miami, Florida 33199, USA 8University of Maryland, College Park, Maryland 20742, USA 9Istituto Nazionale di Fisica Nucleare, Gruppo Collegato Sanitá, Seziona di Roma, 00161 Roma, Italy 10Duke University, Durham, North Carolina 27708, USA 11Rutgers, The State University of New Jersey, Piscataway, New Jersey 08855, USA 12Kharkov Institute of Physics and Technology, Kharkov 61108, Ukraine 13Cairo University, Giza 12613, Egypt 14Kyungpook National University, Taegu City, Korea 15University of Kentucky, Lexington, Kentucky 40506, USA 16Massachusetts Institute of Technology, Cambridge, Massachussetts 02139, USA 17Temple University, Philadelphia, Pennsylvania 19122, USA 18Université Blaise Pascal et CNRS/IN2P3 LPC, 63177 Aubière Cedex, France 19University of Tel Aviv, Tel Aviv 69978, Israel 20Istituto Nazionale di Fisica Nucleare, Sezione di Roma, 00185 Roma, Italy 21Chungnam National University, Taejon 305-764, Korea (Received 10 April 2015; published 15 July 2015)

We present new experimental results of the ^3He spin structure function g_2 in the resonance region at Q^2 values between 1.2 and 3.0 (GeV/c)^2. Spin dependent moments of the neutron were then extracted. Our main result, the resonance contribution to the neutron d_2 matrix element, was found to be small at "=2.4 (GeV/c)^2 and in agreement with the Lattice QCD calculation. The Burkhardt-Cottingham sum rule for ^3He and the neutron was tested with the measured data and using the Wandzura-Wilczek relation for the low x unmeasured region. A small deviation was observed at Q^2 values between 0.5 and 1.2 (GeV/c)^2 for the neutron."

A lead–glass hodoscope calorimeter that was constructed for use in the Jefferson Lab Real Compton Scattering experiment is described. The detector provides a measurement of the coordinates and the energy of scattered photons in the GeV energy range with resolutions of 5mm and 6%/EγGeV. Features of both the detector design and its performance in the high luminosity environment during the experiment are presented.

We have made the first measurements of the virtual Compton scattering process via the e p -> e p gamma exclusive reaction at Q**2 = 1 GeV**2 in the nucleon resonance region. The cross section is obtained at center of mass (CM) backward angle, theta_gamma_gamma*, in a range of total (gamma* p) CM energy W from the proton mass up to W = 1.91 GeV. The data show resonant structures in the first and second resonance regions, and are well reproduced at higher W by the Bethe-Heitler+Born cross section, including t-channel pi0-exchange. At high W, our data, together with existing real photon data, show a striking Q**2 independence. Our measurement of the ratio of H(e,e'p)gamma to H(e,e'p)pi0 cross sections is presented and compared to model predictions.

We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_1 of the neutron and ^3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c)^2. Global duality is observed for the spin-structure function g_1 down to at least Q^2 = 1.8 (GeV/c)^2 in both targets. We have also formed the photon-nucleon asymmetry A_1 in the resonance region for 3He and found no strong Q^2-dependence above 2.2 (GeV/c)^2.

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from protons. Significant contributions to this asymmetry could arise from the contributions of strange form factors in the nucleon. The measured asymmetry is A = −15.05 ± 0.98(stat) ± 0.56(syst) ppm at the kinematic point 〈θlab〉 = 12.3 and 〈Q2〉 = 0.477 (GeV/c)2. Based on these data as well as data on electromagnetic form factors, we extract the linear combination of strange form factors GE + 0.392G s M = 0.014 ± 0.020 ± 0.010 where the first error arises from this experiment and the second arises from the electromagnetic form factor data. This paper provides a full description of the special experimental techniques employed for precisely measuring the small asymmetry, including the first use of a strained GaAs crystal and a laser-Compton polarimeter in a fixed target parity-violation experiment. PACS numbers: 13.60.Fz; 11.30.Er; 13.40.Gp; 14.20.Dh Electronic address: finn@physics.wm.edu Now at: Duke University, Durham, North Carolina 27708 USA Now at: University of Chicago, IL, 60637, USA Electronic address: souder@phy.syr.edu

K. Kramer, D. S. Armstrong, T. D. Averett, W. Bertozzi, S. Binet, C. Butuceanu, A. Camsonne, G. D. Cates, J.-P. Chen, Seonho Choi, E. Chudakov, F. Cusanno, A. Deur, P. Djawotho, D. Dutta, J. M. Finn, H. Gao, F. Garibaldi, O. Gayou, R. Gilman, A. Glamazdin, V. Gorbenko, K. A. Griffioen, J.-O. Hansen, D. W. Higinbotham, W. Hinton, T. Horn, C.W. de Jager, X. Jiang, W. Korsch, J. LeRose, D. Lhuillier, N. Liyanage, D. J. Margaziotis, K. McCormick, Z.-E. Meziani, R. Michaels, B. Milbrath, B. Moffit, S. Nanda, C. F. Perdrisat, R. Pomatsalyuk, V. Punjabi, B. Reitz, J. Roche, R. Roché, M. Roedelbronn, N. Savvinov,0 J. Secrest, J. Singh, S. Širca, K. Slifer, P. Solvignon, D. J. Steiner, R. Suleiman, V. Sulkosky, A. Tobias, A. Vacheret, Y. Xiao, X. Zheng, J. Zhou, L. Zhu, X. Zhu, P. A. Żo lnierczuk,

We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.

A hodoscope calorimeter comprising of 704 lead-glass blocks is described. The calorimeter was constructed for use in the JLab Real Compton Scattering experiment. The detector provides a measurement of the coordinates and the energy of scattered photons in the GeV energy range with resolutions of 5 mm and 6%/\sqrt{E_\gamma [GeV]}, respectively. Design features and performance parameters during the experiment are presented.

We have measured the transverse asymmetry A T (cid:2) in the quasielastic 3 (cid:3) He( (cid:3) e,e (cid:2) ) process with high precision at Q 2 values from 0.1 to 0 . 6(GeV /c ) 2 . The neutron magnetic form factor G nM was extracted at Q 2 values of 0.1 and 0 . 2(GeV /c ) 2 using a nonrelativistic Faddeev calculation which includes both final-state interactions (FSI) and meson-exchange currents (MEC). Theoretical uncertainties due to the FSI and MEC effects were constrained with a precision measurement of the spin-dependent asymmetry in the threshold region of 3 (cid:3) He( (cid:3) e,e (cid:2) ). We also extracted the neutron magnetic form factor G nM at Q 2 values of 0.3 to 0 . 6(GeV /c ) 2 based on plane wave impulse approximation calculations.

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 4He at an average scattering angle = 5.7 degrees and a four-momentum transfer Q2 = 0.091 GeV2 . From these data, for the first time, the strange electric form factor of the nucleon G(E)s can be isolated. The measured asymmetry of A(PV) = (6.72 +/- 0.84(stat) +/- 0.21(syst) x 10(-6) yields a value of G(E)s = -0.038 +/- 0.042(stat) +/- 0.010(syst), consistent with zero.

We report the most precise measurement to date of a parity-violating asymmetry in elastic electron-proton scattering. The measurement was carried out with a beam energy of 3.03 GeV and a scattering angle 〈θlab〉 = 6.0 ◦, with the result APV = (−1.14 ± 0.24 (stat) ± 0.06 (syst)) × 10. From this we extract, at Q = 0.099 GeV, the strange form factor combination GsE + 0.080 G s M = 0.030 ± 0.025 (stat) ± 0.006 (syst) ± 0.012 (FF) where the first two errors are experimental and the last error is due to the uncertainty in the neutron electromagnetic form factor. This result significantly improves current knowledge of GsE and G s M at Q 2 ∼ 0.1GeV. A consistent picture emerges when several measurements at about the same Q value are combined: GsE is consistent with zero while G s M prefers positive values though G s E = G s M = 0 is compatible with the data at 95% C.L.

We report the most precise measurement to date of a parity-violating asymmetry in elastic electron–proton scattering. The measurement was carried out with a beam energy of 3.03 GeV and a scattering angle 〈θlab〉=6.0○, with the result APV=(−1.14±0.24(stat)±0.06(syst))×10−6. From this we extract, at Q2=0.099GeV2, the strange form factor combination GEs+0.080GMs=0.030±0.025(stat)±0.006(syst)±0.012(FF) where the first two errors are experimental and the last error is due to the uncertainty in the neutron electromagnetic form factor. This result significantly improves current knowledge of GEs and GMs at Q2∼0.1GeV2. A consistent picture emerges when several measurements at about the same Q2 value are combined: GEs is consistent with zero while positive values are favored for GMs, though GEs=GMs=0 is compatible with the data at 95% C.L.

The recoil proton polarization was measured in the {sup 2}H(e-vector,e{sup '}p-vector)n reaction in Hall A of the Thomas Jefferson National Accelerator Facility. The electron kinematics were centered on the quasielastic peak (x{sub Bj}{approx_equal}1) and included three values of the squared four-momentum transfer, Q{sup 2}=0.43,1.00 and 1.61 (GeV/c){sup 2}. For Q{sup 2}=0.43 and 1.61 (GeV/c){sup 2}, the missing momentum, p{sub m}, was centered at zero, whereas for Q{sup 2}=1.00 (GeV/c){sup 2} two values of p{sub m} were chosen: 0 and 174 MeV/c. At low p{sub m}, the Q{sup 2} dependence of the longitudinal polarization, P{sub z}{sup '}, is not well described by a state-of-the-art calculation. Further, at higher p{sub m}, a 3.5{sigma} discrepancy was observed in the transverse polarization, P{sub x}{sup '}. Understanding the origin of these discrepancies is important to confidently extract the neutron electric form factor from the analogous {sup 2}H(e-vector,e{sup '}n-vector)p experiment.

The recoil proton polarization was measured in the H-2(e,e(')p)n reaction in Hall A of the Thomas Jefferson National Accelerator Facility. The electron kinematics were centered on the quasielastic peak (x(Bj)approximate to 1) and included three values of the squared four-momentum transfer, Q(2)=0.43,1.00 and 1.61 (GeV/c)(2). For Q(2)=0.43 and 1.61 (GeV/c)(2), the missing momentum, p(m), was centered at zero, whereas for Q(2)=1.00 (GeV/c)(2) two values of p(m) were chosen: 0 and 174 MeV/c. At low p(m), the Q(2) dependence of the longitudinal polarization, P-z('), is not well described by a state-of-the-art calculation. Further, at higher p(m), a 3.5 sigma discrepancy was observed in the transverse polarization, P-x('). Understanding the origin of these discrepancies is important to confidently extract the neutron electric form factor from the analogous H-2(e,e(')n)p experiment.

This paper was published online on 20 May 2005 without several of the authors’ corrections incorporated. Equation (13) has been replaced. The captions of Figs. 16–18 have also been replaced. Typographical errors on pages 4, 6, 14, 15, 18, 19, 22, and 24 have all been corrected. The paper has been corrected as of 8 June 2005. The text is correct in the printed version of the journal.Received 6 June 2005DOI:https://doi.org/10.1103/PhysRevC.71.069902©2005 American Physical Society