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Now showing items 1 - 8 of 8

  • An electromagnetic calorimeter for the JLab real compton scattering experiment

    Hamilton, D. J.   Shahinyan, A.   Wojtsekhowski, B.   Annand, J. R. M.   Chang, T. -H.   Chudakov, E.   Danagoulian, A.   Degtyarenko, P.   Egiyan, K.   Gilman, R.   Gorbenko, V.   Hines, J.   Hovhannisyan, E.   Hyde-Wright, C. E.   de Jager, C. W.   Ketikyan, A.   Mamyan, V. H.   Michaels, R.   Nathan, A. M.   Nelyubin, V.   Rachek, I.   Roedelbrom, M.   Petrosyan, A.   Pomatsalyuk, R.   Popov, V.   Segal, J.   Shestakov, Y.   Templon, J.   Voskanyan, H.  

    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 5 mm and 6%/root E(gamma) GeV. Features of both the detector design and its performance in the high luminosity environment during the experiment are presented. (C) 2011 Elsevier B.V. All rights reserved.
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  • Comparing proton momentum distributions in A=3D2 and 3 nuclei via H-2 H-3 and He-3 (e,e ' p) measurements

    Cruz-Torres, R.   Li, S.   Hauenstein, F.   Schmidt, A.   Nguyen, D.   Abrams, D.   Albataineh, H.   Alsalmi, S.   Androic, D.   Aniol, K.   Armstrong, W.   Arrington, J.   Atac, H.   Averett, T.   Gayoso, C. Ayerbe   Bai, X.   Bane, J.   Barcus, S.   Beck, A.   Bellini, V   Bhatt, H.   Bhetuwal, D.   Biswas, D.   Blyth, D.   Boeglin, W.   Bulumulla, D.   Camsonne, A.   Castellanos, J.   Chen, J-P   Cohen, E. O.   Covrig, S.   Craycraft, K.   Dongwi, B.   Duer, M.   Duran, B.   Dutta, D.   Fuchey, E.   Gal, C.   Gautam, T. N.   Gilad, S.   Gnanvo, K.   Gogami, T.   Gomez, J.   Gu, C.   Habarakada, A.   Hague, T.   Hansen, O.   Hattawy, M.   Hen, O.   Higinbotham, D. W.   Hughes, E.   Hyde, C.   Ibrahim, H.   Jian, S.   Joosten, S.   Karki, A.   Karki, B.   Katramatou, A. T.   Keppel, C.   Khachatryan, M.   Khachatryan, V   Khanal, A.   King, D.   King, P.   Korover, I   Kutz, T.   Lashley-Colthirst, N.   Laskaris, G.   Li, W.   Liu, H.   Liyanage, N.   Lonardoni, D.   Machleidt, R.   Marcucci, L. E.   Markowitz, R.   McClellan, R. E.   Meekins, D.   Beck, S. Mey-Tal   Meziani, Z-E   Michaels, R.   Mihovilovic, M.   Nelyubin, V   Nuruzzaman, N.   Nycz, M.   Obrecht, R.   Olson, M.   Ou, L.   Owen, V   Pandey, B.   Pandey, V   Papadopoulou, A.   Park, S.   Patsyuk, M.   Paul, S.   Petratos, G. G.   Piasetzky, E.   Pomatsalyuk, R.   Premathilake, S.   Puckett, A. J. R.   Punjabi, V   Ransome, R.   Rashad, M. N. H.   Reimer, P. E.   Riordan, S.   Roche, J.   Sammarruca, F.   Santiesteban, N.   Sawatzky, B.   Segarra, E. P.   Schmookler, B.   Shahinyan, A.   Sirca, S.   Sparveris, N.   Su, T.   Suleiman, R.   Szumila-Vance, H.   Tadepalli, A. S.   Tang, L.   Tireman, W.   Tortorici, F.   Urciuoli, G.   Viviani, M.   Weinstein, L. B.   Wojtsekhowski, B.   Wood, S.   Ye, Z. H.   Ye, Z. Y.   Zhang, J.  

    We report the first measurement of the (e, e'p) reaction cross-section ratios for Helium-3 (He-3), Tritium (H-3), and Deuterium (d). The measurement covered a missing momentum range of 40 <=3D p(miss) <=3D 550 MeV/c, at large momentum transfer (< Q(2)> approximate to 1.9 (GeV/c)(2)) and x(B) > 1, which minimized contributions from non quasi-elastic (QE) reaction mechanisms. The data is compared with plane-wave impulse approximation (PWIA) calculations using realistic spectral functions and momentum distributions. The measured and PWIA-calculated cross-section ratios for He-3/d and H-3/d extend to just above the typical nucleon Fermi-momentum (k(F) approximate to 250 MeV/c) and differ from each other by similar to 20%, while for He-3/H-3 they agree within the measurement accuracy of about 3%. At momenta above k(F), the measured He-3/H-3 ratios differ from the calculation by 20% - 50%. Final state interaction (FSI) calculations using the generalized Eikonal Approximation indicate that FSI should change the He-3/H-3 cross-section ratio for this measurement by less than 5%. If these calculations are correct, then the differences at large missing momenta between the He-3/H-3 experimental and calculated ratios could be due to the underlying NN interaction, and thus could provide new constraints on the previously loosely-constrained short-distance parts of the NN interaction. (C) 2019 The Author(s). Published by Elsevier B.V.
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  • Precision measurements of A(1)(n) in the deep inelastic regime

    Parno, D. S.   Flay, D.   Posik, M.   Allada, K.   Armstrong, W.   Averett, T.   Benmokhtar, F.   Bertozzi, W.   Camsonne, A.   Canan, M.   Cates, G. D.   Chen, C.   Chen, J. -P.   Choi, S.   Chudakov, E.   Cusanno, F.   Dalton, M. M.   Deconinck, W.   de Jager, C. W.   Deng, X.   Deur, A.   Dutta, C.   El Fassi, L.   Franklin, G. B.   Friend, M.   Gao, H.   Garibaldi, F.   Gilad, S.   Gilman, R.   Glamazdin, O.   Golge, S.   Gomez, J.   Guo, L.   Hansen, O.   Higinbotham, D. W.   Holmstrom, T.   Huang, J.   Hyde, C.   Ibrahim, H. F.   Jiang, X.   Jin, G.   Katich, J.   Kelleher, A.   Kolarkar, A.   Korsch, W.   Kumbartzki, G.   LeRose, J. J.   Lindgren, R.   Liyanage, N.   Long, E.   Lukhanin, A.   Mamyan, V.   McNulty, D.   Meziani, Z. -E.   Michaels, R.   Mihovilovic, M.   Moffit, B.   Muangma, N.   Nanda, S.   Narayan, A.   Nelyubin, V.   Norum, B.   Nuruzzaman   Oh, Y.   Peng, J. C.   Qian, X.   Qiang, Y.   Rakhman, A.   Riordan, S.   Saha, A.   Sawatzky, B.   Shabestari, M. H.   Shahinyan, A.   Sirca, S.   Solvignon, P.   Subedi, R.   Sulkosky, V.   Tobias, W. A.   Troth, W.   Wang, D.   Wang, Y.   Wojtsekhowski, B.   Yan, X.   Yao, H.   Ye, Y.   Ye, Z.   Yuan, L.   Zhan, X.   Zhang, Y.   Zhang, Y. -W.   Zhao, B.   Zheng, X.  

    We have performed precision measurements of the double-spin virtual-photon asymmetry A(1) on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer and a longitudinally and transversely polarized He-3 target. Our data cover a wide kinematic range 0.277 <=3D x <=3D 0.548 at an average Q(2) value of 3.078(GeV/c)(2), doubling the available high-precision neutron data in this xrange. We have combined our results with world data on proton targets to make a leading-order extraction of the ratio of polarized-to-unpolarized parton distribution functions for up quarks and for down quarks in the same kinematic range. Our data are consistent with a previous observation of an A(1)(n) zero crossing near x =3D 0.5. We find no evidence of a transition to a positive slope in (Delta d + Delta(d) over bar)/(d + (d) over bar) up to x =3D 0.548. (C) 2015 The Authors. Published by Elsevier B.V.
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  • Polarization observables in deuteron photodisintegration below 360 MeV RID B-9493-2011

    Glister, J.   Ron, G.   Lee, B. W.   Gilman, R.   Sarty, A. J.   Strauch, S.   Higinbotham, D. W.   Piasetzky, E.   Allada, K.   Armstrong, W.   Arrington, J.   Arenhoevel, H.   Beck, A.   Benmokhtar, F.   Berman, B. L.   Boeglin, W.   Brash, E.   Camsonne, A.   Calarco, J.   Chen, J. P.   Choi, S.   Chudakov, E.   Coman, L.   Craver, B.   Cusanno, F.   Dumas, J.   Dutta, C.   Feuerbach, R.   Freyberger, A.   Frullani, S.   Garibaldi, F.   Hansen, J. -O.   Holmstrom, T.   Hyde, C. E.   Ibrahim, H.   Ilieva, Y.   de Jager, C. W.   Jiang, X.   Jones, M. K.   Kang, Hyekoo   Kelleher, A.   Khrosinkova, E.   Kuchina, E.   Kumbartzki, G.   LeRose, J. J.   Lindgren, R.   Markowitz, P.   Beck, S. May-Tal   McCullough, E.   Meekins, D.   Meziane, M.   Meziani, Z. -E.   Michaels, R.   Moffit, B.   Norum, B. E.   Oh, Y.   Olson, M.   Paolone, M.   Paschke, K.   Perdrisat, C. F.   Potokar, M.   Pomatsalyuk, R.   Pomerantz, I.   Puckett, A.   Punjabi, V.   Qian, X.   Qiang, Y.   Ransome, R. D.   Reyhan, M.   Roche, J.   Rousseau, Y.   Saha, A.   Sawatzky, B.   Schulte, E.   Schwamb, M.   Shabestari, M.   Shahinyan, A.   Shneor, R.   Sirca, S.   Slifer, K.   Solvignon, P.   Song, J.   Sparks, R.   Subedi, R.   Urciuoli, G. M.   Wang, K.   Wojtsekhowski, B.   Yan, X.   Yao, H.   Zhan, X.   Zhu, X.  

    High precision measurements of induced and transferred recoil proton polarization in d((gamma) over right arrow, (p) over right arrow )n have been performed for photon energies of 277-357 MeV and theta(cm) = 20 degrees-120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. At the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used. (C) 2011 Elsevier B.V. All rights reserved.
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  • High precision measurement of Compton scattering in the 5 GeV region

    Ambrozewicz, P.   Ye, L.   Prok, Y.   Larin, I   Ahmidouch, A.   Baker, K.   Baturin, V   Benton, L.   Bernstein, A.   Burkert, V   Clinton, E.   Cole, P. L.   Collins, P.   Dale, D.   Danagoulian, S.   Davidenko, G.   Demirchyan, R.   Deur, A.   Dolgolenko, A.   Dutta, D.   Dzyubenko, G.   Evdokimov, A.   Fedotov, G.   Feng, J.   Gabrielyan, M.   Gan, L.   Gao, H.   Gasparian, A.   Gevorkyan, N.   Gevorkyan, S.   Glamazdin, A.   Goryachev, V   Guo, L.   Gyurjyan, V   Hardy, K.   He, J.   Isupov, E.   Ito, M. M.   Jiang, L.   Kang, H.   Kashy, D.   Khandaker, M.   Kingsberry, P.   Klein, F.   Kolarkar, A.   Konchatnyi, M.   Korchin, O.   Korsch, W.   Kosinov, O.   Kowalski, S.   Kubantsev, M.   Kubarovsky, A.   Kubarovsky, V   Lawrence, D.   Li, X.   Levillain, M.   Lu, H.   Ma, L.   Martel, P.   Matveev, V   McNulty, D.   Mecking, B.   Micherdzinska, A.   Milbrath, B.   Minehart, R.   Miskimen, R.   Mochalov, V   Morrison, B.   Mtingwa, S.   Nakagawa, I   Overby, S.   Pasyuk, E.   Payen, M.   Park, K.   Pedroni, R.   Phelps, W.   Protopopescu, D.   Rimal, D.   Ritchie, B. G.   Romanov, D.   Salgado, C.   Shahinyan, A.   Sitnikov, A.   Sober, D.   Stepanyan, S.   Stephens, W.   Tarasov, V   Taylor, S.   Teymurazyan, A.   Underwood, J.   Vasiliev, A.   Vishnyakov, V.   Weygand, D. P.   Wood, M.   Zhang, Y.   Zhou, S.   Zihlmann, B.  

    The cross section of atomic electron Compton scattering gamma + e -> gamma' + e' was measured in the 4.400-5.475 GeV photon beam energy region by the PrimEx collaboration at Jefferson Lab with an accuracy of 2.6% and less. The results are consistent with theoretical predictions that include next-to-leading order radiative corrections. The measurements provide the first high precision test of this elementary QED process at beam energies greater than 0.1 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.
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  • High-precision measurement of the proton elastic form factor ratio mu(p)G(E)/G(M) at low Q(2)

    Zhan, X.   Allada, K.   Armstrong, D. S.   Arrington, J.   Bertozzi, W.   Boeglin, W.   Chen, J. -P.   Chirapatpimol, K.   Choi, S.   Chudakov, E.   Cisbani, E.   Decowski, P.   Dutta, C.   Frullani, S.   Fuchey, E.   Garibaldi, F.   Gilad, S.   Gilman, R.   Glister, J.   Hafidi, K.   Hahn, B.   Hansen, J. -O.   Higinbotham, D. W.   Holmstrom, T.   Holt, R. J.   Huang, J.   Huber, G. M.   Itard, F.   de Jager, C. W.   Jiang, X.   Johnson, M.   Katich, J.   de Leo, R.   LeRose, J. J.   Lindgren, R.   Long, E.   Margaziotis, D. J.   Beck, S. May-Tal   Meekins, D.   Michaels, R.   Moffit, B.   Norum, B. E.   Olson, M.   Piasetzky, E.   Pomerantz, I.   Protopopescu, D.   Qian, X.   Qiang, Y.   Rakhman, A.   Ransome, R. D.   Reimer, P. E.   Reinhold, J.   Riordan, S.   Ron, G.   Saha, A.   Sarty, A. J.   Sawatzky, B.   Schulte, E. C.   Shabestari, M.   Shahinyan, A.   Shneor, R.   Sirca, S.   Solvignon, P.   Sparveris, N. F.   Strauch, S.   Subedi, R.   Sulkosky, V.   Vilardi, I.   Wang, Y.   Wojtsekhowski, B.   Ye, Z.   Zhang, Y.  

    We report a new, high-precision measurement of the proton elastic form factor ratio mu(p)G(E)/G(M) for the four-momentum transfer squared Q(2) = 0.3-0.7 (GeV/c)(2). The measurement was performed at Jefferson Lab (JLab) in Hall A using recoil polarimetry. With a total uncertainty of approximately 1%, the new data clearly show that the deviation of the ratio mu(p)G(E)/G(M) from unity observed in previous polarization measurements at high Q(2) continues down to the lowest Q(2) value of this measurement. The updated global fit that includes the new results yields an electric (magnetic) form factor roughly 2% smaller (1% larger) than the previous global fit in this Q(2) range. We obtain new extractions of the proton electric and magnetic radii, which are < r(E)(2)>(1/2) = 0.875 +/- 0.010 fm and < r(M)(2)>(1/2) = 0.867 +/- 0.020 fm. The charge radius is consistent with other recent extractions based on the electron-proton interaction, including the atomic hydrogen Lamb shift measurements, which suggests a missing correction in the comparison of measurements of the proton charge radius using electron probes and the recent extraction from the muonic hydrogen Lamb shift. (C) 2011 Published by Elsevier B.V.
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  • Methods for optical calibration of the BigBite hadron spectrometer

    Mihovilovic, M.   Sirca, S.   Allada, K.   Anderson, B. D.   Annand, J. R. M.   Averett, T.   Camsonne, A.   Chan, R. W.   Chen, J. -P.   Chirapatpimol, K.   de Jager, C. W.   Gilad, S.   Hamilton, D. J.   Hansen, J. -O.   Higinbotham, D. W.   Huang, J.   Jiang, X.   Jin, G.   Korsch, W.   LeRose, J. J.   Lindgren, R. A.   Liyanage, N.   Long, E.   Michaels, R.   Moffit, B.   Monaghan, P.   Nelyubin, V.   Norum, B. E.   Piasetzky, E.   Qian, X.   Qiang, Y.   Riordan, S.   Ron, G.   Rosner, G.   Sawatzky, B.   Shabestari, M.   Shahinyan, A.   Shneor, R.   Subedi, R.   Sulkosky, V.   Watson, J. W.   Zhang, Y. -W.  

    The techniques for the optical calibration of Jefferson Lab's large-acceptance magnetic hadron spectrometer, BigBite, have been examined. The most consistent and stable results were obtained using a method based on singular value decomposition. In spite of the complexity of the optics, the particles' positions and momenta at the target have been precisely reconstructed from the coordinates measured in the detectors by means of a single back-tracing matrix. The technique is applicable to any similar magnetic spectrometer and any particle type. For 0.55 GeV/c protons, we have established a vertex resolution of 1.2 cm, angular resolutions of 7 mrad and 13 mrad (in-plane and out-of-plane, respectively), and a relative momentum resolution of 1.6%. (C) 2012 Elsevier B.V. All rights reserved.
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  • Measurement of the single-spin asymmetry A(y)(0) in quasi-elastic He-3 up arrow(e,e ' n) scattering at 0.4 < Q(2) < 1.0 GeV/c(2)

    Long, E.   Zhang, Y. W.   Mihovilovic, M.   Jin, G.   Sulkosky, V   Kelleher, A.   Anderson, B.   Higinbotham, D. W.   Sirca, S.   Allada, K.   Annand, J. R. M.   Averett, T.   Bertozzi, W.   Boeglin, W.   Bradshaw, P.   Camsonne, A.   Canan, M.   Cates, G. D.   Chen, C.   Chen, J-P   Chudakov, E.   De Leo, R.   Deng, X.   Deur, A.   Dutta, C.   El Fassi, L.   Flay, D.   Frullani, S.   Garibaldi, F.   Gao, H.   Gilad, S.   Gilman, R.   Glamazdin, O.   Golge, S.   Gomez, J.   Hansen, J-O   Holmstrom, T.   Huang, J.   Ibrahim, H.   de Jager, C. W.   Jensen, E.   Jiang, X.   Jones, M.   Kang, H.   Katich, J.   Khanal, H. P.   King, P. M.   Korsch, W.   LeRose, J.   Lindgren, R.   Lu, H-J   Luo, W.   Markowitz, P.   Meziane, M.   Michaels, R.   Moffit, B.   Monaghan, P.   Muangma, N.   Nanda, S.   Norum, B. E.   Pan, K.   Parno, D.   Piasetzky, E.   Posik, M.   Punjabi, V   Puckett, A. J. R.   Qian, X.   Qiang, Y.   Qui, X.   Riordan, S.   Saha, A.   Sawatzky, B.   Shabestari, M.   Shahinyan, A.   Shoenrock, B.   St John, J.   Subedi, R.   Tobias, W. A.   Tireman, W.   Urciuoli, G. M.   Wang, D.   Wang, K.   Wang, Y.   Watson, J.   Wojtsekhowski, B.   Ye, Z.   Zhan, X.   Zhang, Y.   Zheng, X.   Zhao, B.   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-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) =3D 0.46 (GeV/c)(2) to nearly zero at Q(2) =3D 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.
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