Physics
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Item Precise Measurement of the Deuteron Elastic Structure Function A(Q2)(American Physical Society, 1999-02-15) Abbott, D.; Ahmidouch, A.; Anklin, H.; Arvieux, J.; Ball, J.; Beedoe, S.; Beise, E.J.; Bimbot, L.; Boeglin, W.; Breuer, H.; Carlini, R.; Chant, N.S.; Danagoulian, S.; Dow, K.; Ducret, J.-E.; Dunne, J.; Ent, R.; Ewell, L.; Eyraud, L.; Furget, C.; Garcon, M.; Gilman, R.; Glashausser, C.; Gueye, P.; Gustafsson, K.; Hafidi, K.; Honegger, A.; Jourdan, J.; Kox, S.; Kumbartzki, G.; Lu, L.; Lung, A.; Mack, D.; Markowitz, P.; McIntyre, J.; Meekins, D.; Merchez, F.; Mitchell, J.; Mohring, R.; Mtingwa, S.; Mrktchyan, H.; Pitz, D.; Qin, L.; Ransome, R.; Real, J.-S.; Roos, P.G.; Rutt, P.; Sawafta, R.; Stepanyan, S.; Tieulent, R.; Tomasi-Gustafsson, E.; Turchinetz, W.; Vansyoc, K.; Volmer, J.; Voutier, E.; Vulcan, W.; Williamson, C.; Wood, S.A.; Yan, C.; Zhao, J.; Zhao, W.; The Jefferson Lab t20 CollaborationThe A(Q2) structure function in elastic electron-deuteron scattering was measured at six momentum transfers Q2 between 0.66 and 1.80(GeV/c)2 in Hall C at Jefferson Laboratory. The scattered electrons and recoil deuterons were detected in coincidence, at a fixed deuteron angle of 60.5°. These new precise measurements resolve discrepancies between older sets of data. They put significant constraints on existing models of the deuteron electromagnetic structure, and on the strength of isoscalar meson exchange currents.Item Measurements of Deuteron Photodisintegration up to 4.0 GeV(American Physical Society, 1998-11-23) Bochna, C.; Terburg, B.P.; Abbott, D.J.; Ahmidouch, A.; Armstrong, C.S.; Arrington, J.; Assamagan, K.A.; Baker, O.K.; Barrow, S.P.; Beatty, D.P.; Beck, D.H.; Beedoe, S.Y.; Beise, E.J.; Belz, J.E.; Bosted, P.E.; Brash, E.J.; Breuer, H.; Cadman, R.V.; Cardman, L.; Carlini, R.D.; Cha, J.; Chant, N.S.; Collins, G.; Cothran, C.; Cummings, W.J.; Danagoulian, S.; Duncan, F.A.; Dunne, J.A.; Dutta, D.; Eden, T.; Ent, R.; Filippone, B.W.; Forest, T.A.; Fortune, H.T.; Frolov, V.V.; Gao, H.; Geesaman, D.F.; Gilman, R.; Gueye, P.L.J.; Gustafsson, K.K.; Hansen, J.-O.; Harvey, M.; Hinton, W.; Holt, R.J.; Jackson, H.E.; Keppel, C.E.; Khandaker, M.A.; Kinney, E.R.; Klein, A.; Koltenuk, D.M.; Kumbartzki, G.; Lung, A.F.; Mack, D.J.; Madey, R.; Markwoitz, P.; McFarlane, K.W.; McKeown, R.D.; Meekins, D.G.; Meziani, Z.-E.; Miller, M.A.; Mitchell, J.H.; Mkrtchyan, H.G.; Mohring, R.M.; Napolitano, J.; Nathan, A.M.; Niculescu, G.; Niculescu, I.; O'Neill, T.G.; Owen, B.R.; Pate, S.F.; Potterveld, D.H.; Price, J.W.; Rakness, G.L.; Ransome, R.; Reinhold, J.; Rutt, P.M.; Salgado, C.W.; Savage, G.; Segel, R.; Simicevic, N.; Stoler, P.; Suleiman, R.; Tang, L.; van Westrum, D.; Vulcan, W.F.; Williamson, S.; Witkowski, M.T.; Wood, S.A.; Yan, C.; Zeidman, B.The first measurements of the differential cross section for the d(γ,p)n reaction up to 4.0 GeV were performed at the Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson Laboratory. We report the cross sections at the proton center-of-mass angles of 36°, 52°, 69°, and 89°. These results are in reasonable agreement with previous measurements at lower energy. The 89° and 69° data show constituent-counting-rule behavior up to 4.0 GeV photon energy. The 52° and 36° data disagree with the counting-rule behavior. The quantum chromodynamics (QCD) model of nuclear reactions involving reduced amplitudes disagrees with the present data.Item Exclusive Electron Scattering from Deuterium at High Momentum Transfer(American Physical Society, 1995-06-12) Bulten, H.J.; Anthony, P.L.; Arnold, R.G.; Arrington, J.; Beise, E.J.; Belz, E.; van Bibber, K.; Bosted, P.E.; van den Brand, J.F.J.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.S.; Ent, R.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearhart, R.A.; Geesaman, D.F.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Keppel, C.E.; Kinney, E.; Kuhn, S.E.; Lee, K.; Lorenzon, W.; Lung, A.; Makins, N.C.R.; Margaziotis, D.J.; McKeown, R.D.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; O'Neill, T.G.; Papavassiliou, V.; Petratos, G.G.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; White, J.L.; Zeidman, B.Cross sections are presented for the reaction 2H(e,e′p)n for momentum transfers in the range 1.2≤Q2≤6.8(GeV/c)2 and for missing momenta from 0 to 250 MeV/c. The longitudinal-transverse interference structure function has been separated at Q2 = 1.2(GeV/c)2. The observables are compared to calculations performed in nonrelativistic and relativistic frameworks. The data are best described by a fully relativistic calculation.Item Measurement of the Proton's Neutral Weak Magnetic Form Factor(American Physical Society, 1997-05-19) Mueller, B.; Beck, D.H.; Beise, E.J.; Candell, E.; Cardman, L.; Carr, R.; DiBari, R.C.; Dodson, G.; Dow, K.; Duncan, F.; Farkhondeh, M.; Filippone, B.W.; Forest, T.; Gao, H.; Korsch, W.; Kowalski, S.; Lung, A.; McKeown, R.D.; Mohring, R.; Napolitano, J.; Nilsson, D.; Pitt, M.; Simicevic, N.; Terburg, B.; Wells, S.P.; SAMPLE CollaborationWe report the first measurement of the parity-violating asymmetry in elastic electron scattering from the proton. The asymmetry depends on the neutral weak magnetic form factor of the proton which contains new information on the contribution of strange quark-antiquark pairs to the magnetic moment of the proton. We obtain the value GMZ = 0.34±0.09±0.04±0.05n.m. at Q2 = 0.1 (GeV/c)2.Item Transverse-Longitudinal Asymmetry in the Quasielastic 3He⃗(e⃗, e′) Reaction(The American Physical Society, 1995-01-30) Hansen, J.-O.; Titko, M.A.; DeSchepper, D.; Dodson, G.; Donnelly, T.W.; Ent, K.; Farkhondeh, M.; Korsch, W.; Kramer, L.H.; Lee, K.; Makins, N.C.R.; Milner, R.G.; Tieger, D.R.; Welch, T.P.; Jones, C.E.; Arrington, J.; Beise, E.J.; Bray, B.; Carr, R.W.; Filippone, B.W.; Gao, H.; Lung, A.; McKeown, R.D.; Mueller, B.; Pitt, M.L.; Schulze, R.-W.; Sauer, U.; Candell, E.; Napolitano, J.; Tripp, C.; Wojtsekhowski, B.B.; Lorenzon, W.; Dow R.The transverse-longitudinal asymmetry ATL′ in 3He⃗(e⃗, e′) quasielastic scattering at momentum transfer Q2=0.14 (GeV/c)2 has been measured to be 1.52 ± 0.55(stat) ± 0.15(syst)%. The plane wave impulse approximation (PWIA) prediction for this measurement ranges from 2.1% to 2.9%, where the variation is due to uncertainty in the initial state wave function, nucleon form factors, and off-shell prescription. The data may suggest a suppression with respect to the PWIA, which has also been observed for the unpolarized longitudinal response function.Item Two-Body Photodisintegration of the Deuteron up to 2.8 GeV(The American Physical Society, 1995-01) Belz, J.E.; Potterveld, D.H.; Anthony, P.; Arnold, R.G.; Arrington, J.; Beck, D.; Beise, E.J.; Bosted, P.E.; Bulten, H.-J.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.; Ent, R.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearhart, R.A.; Geesaman, D.F.; Hansen, J.-O.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Keppel, C.E.; Kinney, E.R.; Kuhn, S.; Lee, K.; Lorenzon, W.; Makins, N.C.R.; Lung, A.; Margaziotis, D.J.; McKeown, R.D.; Meziani, Z.E.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; O'Neill, T.G.; Papavassiliou, V.; Petratos, G.G.; Rock, S.E.; Segel, R.E.; Spengos, M.; Szalta, Z.M.; Tao, L.H.; van Bibber, K.; van der Brand, F.J.; White, J.L.; Zeidman, B.Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 to 2.8 GeV and center-of-mass angles from 37° to 90°. The measured energy dependence of the cross section at θc.m.=90° is in agreement with the constituent counting rules.Item Momentum transfer dependence of nuclear transparency from the quasielastic 12C(e,e’p) reaction(1994-03) Makins, N.C.R.; Ent, R.; Chapman, M.S.; Hansen, J.-O.; Lee, K.; Milner, R.G.; Nelson, J.; Bosted, P.E.; Keppel, C.E.; Lung, A.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; White, J.L.; Coulter, K.P.; Geesaman, D.F.; Holt, R.J.; Jackson, H.E.; Papavassiliou, V.; Potterveld, D.H.; Zeidman, B.; Arrington, J.; Beise, E.J.; Belz, E.; Filippone, B.W.; Gao, H.; Lorenzon, W.; Mueller, B.; McKeown, R.D.; O'Neill, T.G.; Epstein, M.; Margaziotis, D.J.; Napolitano, J.; Anthony, P.L.; van Bibber, K.; Dietrich, F.S.; Gearhart, R.A.; Petratos, G.G.; Kuhn, S.E.The cross section for quasielastic 12C(e,e’p) scattering has been measured at momentum transfer Q2=1, 3, 5, and 6.8 (GeV/c)2. The results are consistent with scattering from a single nucleon as the dominant process. The nuclear transparency is obtained and compared with theoretical calculations that incorporate color transparency effects. No significant rise of the transparency with Q2 is observed.Item Measurement of tensor polarization in elastic electron-deuteron scattering in the momentum-transfer range 3.8≤q≤4.6 fm-1(1991-07) The, I.; Arvieux, J.; Beck, D.H.; Beise, E.J.; Boudard, A.; Cairns, E.B.; Cameron, J.M.; Dodson, G.W.; Dow, K.A.; Farkhondeh, M.; Fielding, H.W.; Flanz, J.B.; Garcon, M.; Goloskie, R.; Hoibraten, S.; Jourdan, J.; Kowalski, S.; Lapointe, C.; McDonald, W.J.; Ni, B.; Pham, L.D.; Redwine, R.P.; Rodning, N.L.; Roy, G.; Schulze, M.E.; Souder, P.A.; Soukup, J.; Turchinetz, W.E.; Williamson, C.F.; Wilson, K.E.; Wood, S.A.; Zeigler, W.The tensor polarization t20 of the recoil deuteron in elastic e-d scattering has been measured for three values of four-momentum transfer, q=3.78, 4.22, and 4.62 fm-1. The data have been used to locate the first node in the charge monopole form factor of the deuteron at q=4.39±0.16 fm-1. The results for t20 are in reasonable agreement with expectations based on the nucleon-meson description of nuclear dynamicsItem Measurement of inclusive quasielastic scattering of polarized electrons from polarized 3He(1990-08) Woodward, C.E.; Beise, E.J.; Belz, J.E.; Carr, R.W.; Filippone, B.W.; Lorenzon, W.B.; McKeown, R.D.; Mueller, B.; O'Neill, T.G.; Dodson, G.; Dow, K.; Farkhondeh, M.; Kowalski, S.; Lee, K.; Makins, N.; Milner, R.; Thompson, A.; Tieger, D.; van den Brand, J.; Young, A.; Yu, X.; Zumbro, J.We report a measurement of the asymmetry in spin-dependent quasielastic scattering of longitudinally polarized electrons from a polarized 3He gas target. This measurement represents the first demonstration of a new method for studying electromagnetic nuclear structure: the scattering of polarized electrons from a polarized nuclear target. The measured asymmetry is in good agreement with a Faddeev calculation and supports the picture of spin-dependent quasielastic scattering from polarized 3He as predominantly scattering from a polarized neutron.Item Proton propagation in nuclei studied in the A dependence of the (e,e’p) reaction in the quasifree region(1989-08) Geesaman, D.F.; Gilman, R.; Green, M.C.; Holt, R.J.; Schiffer, J.P.; Zeidman, B.; Garino, G.; Saber, M.; Segel, R.E.; Beise, E.J.; Dodson, G.W.; Hoibraten, S.; Pham, L.D.; Redwine, R.P.; Sapp, W.W.; Williamson, C.F.; Wood, S.A.; Chant, N.S.; Roos, P.G.; Silk, J.D.; Deady, M.; Maruyama, X.K.The A dependence of the (e,e’p) reaction in the quasifree region has been measured at an average Q2 of 0.33 (GeV/c)2 for targets of 12C, 27Al, 58Ni, and 181Ta. The outgoing proton kinetic energy was 180±30 MeV. By comparing the ratio of (e,e’p) coincidence to (e,e’) singles yields, average proton transmissions are obtained for each target. The resulting ‘‘mean free path’’ or, more precisely, the attenuation length for protons in the nucleus is significantly longer than expectations based on the free nucleon-nucleon cross section.
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