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

Y. Qiang, J. Annand, J. Arrington, Ya.I. Azimov, W. Bertozzi, G. Cates, J. P. Chen, Seonho Choi, E. Chudakov, F. Cusanno, C.W. de Jager, M. Epstein, R.J. Feuerbach, F. Garibaldi, O. Gayou, R. Gilman, 6 J. Gomez, D.J. Hamilton, J.-O. Hansen, D.W. Higinbotham, T. Holmstrom, M. Iodice, X. Jiang, M. Jones, J. LeRose, R. Lindgren, N. Liyanage, D.J. Margaziotis, P. Markowitz, V. Mamyan, R. Michaels, Z.-E. Meziani, P. Monaghan, C. Muñoz-Camacho, V. Nelyubin, K. Paschke, E. Piasetzky, I. Rachek, P.E. Reimer, J. Reinhold, B. Reitz, R. Roche, A. Saha, A.J. Sarty, E. Schulte, A. Shahinyan, R. Sheyor, J. Singh, I.I. Strakovsky, R. Subedi, R. Suleiman, V. Sulkosky, B. Wojtsekhowski, and X. Zheng

Recommended Citation Yan, X.; Allada, K.; Aniol, K.; Annand, J. R. M.; Averett, Todd D.; Benmokhtar, F.; Bertozzi, W.; Bradshaw, P. C.; Bosted, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J. -P.; Chen, W.; Chirapatpimol, K.; Chudakov, E.; Cisbani, E.; Cornejo, J. C.; Cusanno, F.; Dalton, M. M.; Deconinck, W.; Katich, J.; Kelleher, A.; and Zhao, B., First measurement of unpolarized semi-inclusive deep-inelastic scattering cross sections from a He-3 target (2017). PHYSICAL REVIEW C, 95(3). 10.1103/PhysRevC.95.035209

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either H-2 or He-3 targets. In order to extract useful neutron information from a He-3 target, one must understand how the neutron in a He-3 system differs from a free neutron by taking into account nuclear effects such as final state interactions and meson exchange currents. The target single spin asymmetry A(y)(0) is an ideal probe of such effects, as any deviation from zero indicates effects beyond plane wave impulse approximation. New measurements of the target single spin asymmetry A(y)(0) at Q(2) of 0.46 and 0.96 (GeV/c)(2) were made at Jefferson Lab using the quasi-elastic He-3 up arrow(e, e'n) reaction. Our measured asymmetry decreases rapidly, from > 20% at Q(2) = 0.46 (GeV/c)(2) to nearly zero at Q(2) = 0.96 (GeV/c)(2), demonstrating the fall-off of the reaction mechanism effects as Q(2) increases. We also observed a small epsilon-dependent increase in A(y)(0) compared to previous measurements, particularly at moderate Q(2). This indicates that upcoming high Q(2) measurements from the Jefferson Lab 12 GeV program can cleanly probe neutron structure from polarized He-3 using plane wave impulse approximation. (C) 2019 The Authors. Published by Elsevier B.V.

Measurement of the single-spin asymmetry Ay in quasi-elastic 3He↑(e, e′n) scattering at 0.4 < Q 2 < 1.0 GeV/c2 E. Long a,∗, Y.W. Zhang b, M. Mihovilovič c, G. Jin d, V. Sulkosky e, A. Kelleher e, B. Anderson f, D.W. Higinbotham g, S. Širca c, K. Allada g, J.R.M. Annand h, T. Averett i, W. Bertozzi e, W. Boeglin j, P. Bradshaw i, A. Camsonne g, M. Canan k, G.D. Cates d, C. Chen l, J.-P. Chen g, E. Chudakov g, R. De Leo m, X. Deng d, A. Deur g, C. Dutta n, L. El Fassi b, D. Flay o, S. Frullani p, F. Garibaldi p, H. Gao q, S. Gilad e, R. Gilman g, O. Glamazdin r, S. Golge k, J. Gomez g, J.-O. Hansen g, T. Holmstrom s, J. Huang e,t, H. Ibrahim u, C.W. de Jager g, E. Jensen v, X. Jiang t, M. Jones g, H. Kang w, J. Katich i, H.P. Khanal j, P.M. King x, W. Korsch n, J. LeRose g, R. Lindgren d, H.-J. Lu y, W. Luo z, P. Markowitz j, M. Meziane i, R. Michaels g, B. Moffit g, P. Monaghan l, N. Muangma e, S. Nanda g, B.E. Norum d, K. Pan e, D. Parno aa, E. Piasetzky ab, M. Posik o, V. Punjabi ac, A.J.R. Puckett e,t, X. Qian q, Y. Qiang g, X. Qui z, S. Riordan d,e, A. Saha g,1, B. Sawatzky g, M. Shabestari d, A. Shahinyan ad, B. Shoenrock ae, J. St. John s, R. Subedi af, W.A. Tobias d, W. Tireman ae, G.M. Urciuoli p, D. Wang d, K. Wang d, Y. Wang ag, J. Watson f, B. Wojtsekhowski g, Z. Ye l, X. Zhan e, Y. Zhang z, X. Zheng d, B. Zhao i, L. Zhu l

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either H or He targets. In order to extract useful neutron information from a He target, one must understand how the neutron in a He system differs from a free neutron by taking into account nuclear effects such as final state interactions and meson exchange currents. The target single spin asymmetry Ay is an ideal probe of such effects, Corresponding author Email address: elena.long@unh.edu (E. Long) Deceased 9 May 2011. Preprint submitted to Physics Letters B May 14, 2019 as any deviation from zero indicates effects beyond plane wave impulse approximation. New measurements of the target single spin asymmetry Ay at Q 2 of 0.46 and 0.96 (GeV/c) were made at Jefferson Lab using the quasi-elastic 3He(e, en) reaction. Our measured asymmetry decreases rapidly, from > 20% at Q = 0.46 (GeV/c) to nearly zero at Q = 0.96 (GeV/c), demonstrating the fall-off of the reaction mechanism effects as Q increases. We also observed a small ǫ-dependent increase in Ay compared to previous measurements, particularly at moderate Q . This indicates that upcoming high Q measurements from the Jefferson Lab 12 GeV program can cleanly probe neutron structure from polarized He using plane wave impulse approximation.

Due to the lack of free neutron targets, studies of the structure of the neutron are typically made by scattering electrons from either ^2H or ^3He targets. In order to extract useful neutron information from a ^3He target, one must understand how the neutron in a ^3He system differs from a free neutron by taking into account nuclear effects such as final state interactions and meson exchange currents. The target single spin asymmetry A_y^0 is an ideal probe of such effects, as any deviation from zero indicates effects beyond plane wave impulse approximation. New measurements of the target single spin asymmetry A_y^0 at Q^2 of 0.46 and 0.96 (GeV/c)^2 were made at Jefferson Lab using the quasi-elastic ^3He^↑(e,e'n) reaction. Our measured asymmetry decreases rapidly, from >20% at Q^2=0.46 (GeV/c)^2 to nearly zero at Q^2=0.96 (GeV/c)^2, demonstrating the fall-off of the reaction mechanism effects as Q^2 increases. We also observed a small ϵ-dependent increase in A_y^0 compared to previous measurements, particularly at moderate Q^2. This indicates that upcoming high Q^2 measurements from the Jefferson Lab 12 GeV program can cleanly probe neutron structure from polarized ^3He using plane wave impulse approximation.

Received 18 May 2018DOI:https://doi.org/10.1103/PhysRevC.98.019907©2018 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCharge distributionsForm factorsNuclear charge distributionParticle interactionsParticles & FieldsNuclear Physics

The GEp-III and GEp-2 gamma experiments, carried out in Jefferson Lab's Hall C from 2007-2008, consisted of measurements of polarization transfer in elastic electron-proton scattering at momentum transfers of Q(2) = 2.5, 5.2, 6.8, and 8.54 GeV (2). These measurements were carried out to improve knowledge of the proton electromagnetic form factor ratio R = mu(P)G(E)(P)/G(M)(P) at large values of Q(2) and to search for effects beyond the Born approximation in polarization transfer observables at Q(2) = 2.5 GeV2. The final results of both experiments were reported in a recent archival publication. A full reanalysis of the data from both experiments was carried out in order to reduce the systematic and, for the GEp-2 gamma experiment, statistical uncertainties. This technical note provides additional details of the final analysis omitted from the main publication, including the final evaluation of the systematic uncertainties.

Subsequent to the release of our original paper, we discovered in the context of preparing our technical supplement [1] for journal publication that a typographical error had existed in the text file that the analysis program used to construct the beam polarization for both the original analysis, published in Ref. [2], and our final analysis. The electron-beam polarization P e and the analyzing power A y cancel exactly in the ratio R , which is proportional to the ratio P t / P l of the transferred polarization components. On the other hand, the extraction of the relative e dependence of P l / P Born l relies on knowledge of the beam polarization. As such, data taking was interrupted roughly every two days during the GEp - 2 ? experiment to perform invasive measurements of the beam polarization using the Hall C Moller polarimeter [3]. The run range affected by the typographical error was entirely contained within the data collected at Q 2 = 2.5 GeV 2 with a beam energy of E e = 3.680 GeV during January 2008. The data from this configuration were combined with the data collected at E e = 3.548 GeV due to the nearly complete overlap of these two settings in terms of Q 2 and e acceptance. It is worth remarking that this typographical error went unnoticed for so long because it only affected a small fraction of the data (less than half of the combined data for ? e ? = 0.790 ) and the difference between the actually assigned beam polarization and the polarization that should have been assigned was comparable in magnitude to the point-to-point systematic uncertainty of the measurement itself. As such, its effect did not show up in various diagnostic plots and statistical tests, such as the time stability of the extracted P l / P Born l ratio. The data for both E e = 3.548 and E e = 3.680 GeV were reprocessed using the corrected beam polarizations to determine the effect of the typographical error on the combined physics results at ? e ? = 0.790 . Because the value of P e cancels in the ratio R , changes in the assumed beam polarization can only affect the results for R via statistical fluctuations due to changes in the relative weighting of different run ranges in the unbinned maximum-likelihood estimators for R . These effects are negligible on the scale of both the statistical and the systematic uncertainties of the data. More noticeable changes are expected in the ratio P l / P Born l since the extracted value of P l is inversely proportional to the assumed value of P e . Table I shows the effect of the corrected beam polarization database on the polarization transfer observables for the combined data for the ? e ? = 0.790 setting, the only measurement affected by the typographical error. The analyzing power did not need to be recalibrated since it was determined using the ? e ? = 0.153 data, which were not affected by the typographical error. As expected, the change in the ratio R is negligible. The value of P Born l , which is computed event by event from the global fit described in the Appendix of the original paper and does not depend on P e , is also unchanged. The magnitudes of P t , P l , and P l / P Born l are reduced by a common multiplicative factor, reflecting the fact that the beam polarization had been underestimated for the run range affected by the typographical error. The most important result of the corrected analysis is that the ratio P l / P Born l has decreased by 0.0024 from 1.0167 to 1.0143, a change comparable in magnitude to the statistical uncertainty but small compared to the total and point-to-point systematic uncertainties. The P l / P Born l result for the original publication [2] would be reduced by the same multiplicative factor as the final result. The physics conclusions of both publications are not materially changed by this correction. (Table Presented). (Figure Presented).

Background: Measurements of the neutron charge form factor, G(E)(n), are challenging because the neutron has no net charge. In addition, measurements of the neutron form factors must use nuclear targets which require accurately accounting for nuclear effects. Extracting G(E)(n) with different targets and techniques provides an important test of our handling of these effects. Purpose: The goal of the measurement was to use an inclusive asymmetry measurement technique to extract the neutron charge form factor at a four-momentum transfer of 1 (GeV/c)(2). This technique has very different systematic uncertainties than traditional exclusive measurements and thus serves as an independent check of whether nuclear effects have been taken into account correctly. Method: The inclusive quasielastic reaction (3)(He)over right arrowe((e)over right arrow ,e') was measured at Jefferson Laboratory. The neutron electric form factor, G(E)(n), was extracted at Q(2) = 0.98 (GeV/c)(2) from ratios of electron-polarization asymmetries measured for two orthogonal target spin orientations. This Q(2) is high enough that the sensitivity to G(E)(n) is not overwhelmed by the neutron magnetic contribution, and yet low enough that explicit neutron detection is not required to suppress pion production. Results: The neutron electric form factor, G(E)(n), was determined to be 0.0414 +/- 0.0077 (stat) +/- 0.0022 (syst), providing the first high-precision inclusive extraction of the neutron's charge form factor. Conclusions: The use of the inclusive quasielastic (3)(He)over right arrowe((e)over right arrow ,e') with a four-momentum transfer near 1 (GeV/c)(2) has been used to provide a unique measurement of G(E)(n). This new result provides a systematically independent validation of the exclusive extraction technique results and implies that the nuclear corrections are understood. This is contrary to the proton form factor where asymmetry and differential cross section measurements have been shown to have large systematic differences.

We report the measurement of the beam-vector and tensor asymmetries A_{ed}^{V} and A_{d}^{T} in quasielastic (e[over →],e^{'}p) electrodisintegration of the deuteron at the MIT-Bates Linear Accelerator Center up to missing momentum of 500  MeV/c. Data were collected simultaneously over a momentum transfer range 0.1<Q^{2}<0.5  (GeV/c)^{2} with the Bates Large Acceptance Spectrometer Toroid using an internal deuterium gas target polarized sequentially in both vector and tensor states. The data are compared with calculations. The beam-vector asymmetry A_{ed}^{V} is found to be directly sensitive to the D-wave component of the deuteron and has a zero crossing at a missing momentum of about 320  MeV/c, as predicted. The tensor asymmetry A_{d}^{T} at large missing momentum is found to be dominated by the influence of the tensor force in the neutron-proton final-state interaction. The new data provide a strong constraint on theoretical models.

Short-Range Correlations (SRCs) are the term used to describe pairs of nucleons with large relative momenta and small center-of-mass momenta compared to the nuclear Fermi momentum (kF ). Recent studies indicate that SRCs account for 20–25% of the nucleons in medium to heavy nuclei, make up essentially all nucleons with momentum greater than kF , and contribute most of the kinetic energy carried by nucleons in nuclei. Based on these and other findings, recent works found intriguing implications of SRCs for bound nucleon structure functions and the EMC effect, twonucleon knockout processes in neutrino-nucleus scattering measurements, the density dependence of the nuclear symmetry energy and more. Some of the most intriguing SRC results that have come out of the JLab 6 GeV era have been related to asymmetric nuclei, specifically that in neutron-rich nuclei, protons can have large average kinetic energy compared to neutrons, despite being the minority species. The current best data are limited, however. The myriad of (e, e′) measurements on different nuclear targets do not allow separation of proton and neutron contributions. The existing semi-inclusive and exclusive measurements only cover a few species—either light symmetric nuclei, or a few heavy elements— preventing a systematic study of the nuclear mass and proton-neutron asymmetry dependencies. We propose to systematically study the individual probabilities for finding SRC protons and neutrons in neutron-rich symmetric and asymmetric nuclei (d, He, Be, B, C, Si, Ar, Ca, Ti and Fe), complementing the approved 12 GeV inclusive EMC and SRC experiments on the same nuclei. To this end, we propose measuring the (e, e′p) reaction in kinematics dominated by scattering off mean-field (k ≤ kF ) and SRC pairs (k ≥ kF ). We will extract absolute and reduced cross sections (distorted spectral functions) and cross-section ratios as a function of missing energy and momentum. The measurement results will be used to determine the separate SRC pairing probabilities for protons and neutrons in order to determine how pairing depends on nuclear mass and proton-neutron asymmetry. These probabilities will also be directly compared to effective ab-initio calculations and used to constrain nuclear contact terms. We will use 25–40 μA of the 11 GeV beam in Hall-C, detecting the scattered electrons in the SHMS in coincidence with the knocked out protons in the HMS. We request 7 days of beam-time to significantly improve our quantitative understanding of nucleon pairing in nuclei.

A x-ray inspection system utilizing a continuous-wave 9 MeV rhodotron x-ray source for scanning cargo containers is presented. This system scans for contraband, anomalies, stowaway passengers, and nuclear threats for trucks and towed cargo containers. A transmission image is generated concurrently with a 3D image of the cargo, the latter presenting material information in the form of atomic number and density. Neutrons from photofission are also detected during each scan. In addition, nuclear resonance fluorescence detectors are capable of identifying specific isotopes. This system has recently been deployed at the Port of Boston.

The unpolarized semi-inclusive deep-inelastic scattering (SIDIS) differential cross sections in He3(e,e′π±)X have been measured for the first time in Jefferson Lab experiment E06-010 with a 5.9GeVe− beam on a He3 gas target. The experiment focuses on the valence quark region, covering a kinematic range 0.12<xbj<0.45,1<Q2<4(GeV/c)2,0.45<zh<0.65, and 0.05<Pt<0.55GeV/c. The extracted SIDIS differential cross sections of π± production are compared with existing phenomenological models while the He3 nucleus approximated as two protons and one neutron in a plane-wave picture, in multidimensional bins. Within the experimental uncertainties, the azimuthal modulations of the cross sections are found to be consistent with zero.

Background: Interest in the behavior of nucleon electromagnetic form factors at large momentum transfers has steadily increased since the discovery, using polarization observables, of the rapid decrease of the ratio GEp/GMp of the proton's electric and magnetic form factors for momentum transfers Q2≳1 GeV2, in strong disagreement with previous extractions of this ratio using the traditional Rosenbluth separation technique. Purpose: The GEp-III and GEp-2γ experiments were carried out in Jefferson Laboratory's (JLab's) Hall C from 2007 to 2008, to extend the knowledge of GEp/GMp to the highest practically achievable Q2 given the maximum beam energy of 6 GeV and to search for effects beyond the Born approximation in polarization transfer observables of elastic ep scattering. This article provides an expanded description of the common experimental apparatus and data analysis procedures, and reports the results of a final reanalysis of the data from both experiments, including the previously unpublished results of the full-acceptance dataset of the GEp-2γ experiment. Methods: Polarization transfer observables in elastic ep→ep scattering were measured at central Q2 values of 2.5, 5.2, 6.8, and 8.54 GeV2. At Q2=2.5GeV2, data were obtained for central values of the virtual photon polarization parameter e of 0.149, 0.632, and 0.783. The Hall C High Momentum Spectrometer detected and measured the polarization of protons recoiling elastically from collisions of JLab's polarized electron beam with a liquid hydrogen target. A large-acceptance electromagnetic calorimeter detected the elastically scattered electrons in coincidence to suppress inelastic backgrounds. Results: The final GEp-III data are largely unchanged relative to the originally published results. The statistical uncertainties of the final GEp-2γ data are significantly reduced at e=0.632 and 0.783 relative to the original publication. Conclusions: The final GEp-III results show that the decrease with Q2 of GEp/GMp continues to Q2=8.5GeV2, but at a slowing rate relative to the approximately linear decrease observed in earlier Hall A measurements. At Q2=8.5GeV2, GEp/GMp remains positive but is consistent with zero. At Q2=2.5GeV2, GEp/GMp derived from the polarization component ratio R∝Pt/Pl shows no statistically significant e dependence, as expected in the Born approximation. On the other hand, the ratio Pl/PlBorn of the longitudinal polarization transfer component to its Born value shows an enhancement of roughly 1.7% at e=0.783 relative to e=0.149, with ≈2.2σ significance based on the total uncertainty, implying a similar effect in the transverse component Pt that cancels in the ratio R.

We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element d(2) of the neutron (d(2)(n)) was conducted. The quantity d(2)(n) represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the He-3 spin structure functions, g(1) and g(2), after nuclear corrections had been applied to these moments. The structure functions were obtained from a measurement of the unpolarized cross section and of double-spin asymmetries in the scattering of a longitudinally polarized electron beam from a transversely and a longitudinally polarized He-3 target. The measurement kinematics included two average Q(2) bins of 3.2 GeV2 and 4.3 GeV2, and Bjorken-x 0.25 <= x <= 0.90 covering the deep inelastic and resonance regions. We have found that d(2)(n) is small and negative for < Q(2)> = 3.2 GeV2, and even smaller for < Q(2)> = 4.3 GeV2, consistent with the results of a lattice QCD calculation. The twist-4 matrix element f(2)(n) was extracted by combining our measured d(2)(n) with the world data on the first moment in x of g(1)(n), Gamma(n)(1). We found f(2)(n) to be roughly an order of magnitude larger than d(2)(n). Utilizing the extracted d(2)(n) and f(2)(n) data, we separated the Lorentz color force into its electric and magnetic components, F-E(y,n) and F-B(y,n), and found them to be equal and opposite in magnitude, in agreement with the predictions from an instanton model but not with those from QCD sum rules. Furthermore, using the measured double-spin asymmetries, we have extracted the virtual photon-nucleon asymmetry on the neutron A(1)(n), the structure function ratio g(1)(n)/F-1(n), and the quark ratios (Delta u + Delta(u) over bar)/(u + (u) over bar) and (Delta d + Delta(d) over bar)/(d + (d) over bar). These results were found to be consistent with deep-inelastic scattering world data and with the prediction of the constituent quark model but at odds with the perturbative quantum chromodynamics predictions at large x.