Physics
Permanent URI for this communityhttp://hdl.handle.net/1903/2269
Browse
13 results
Search Results
Item Strange-Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment(American Physical Society, 2005-08-26) Armstrong, D.S.; Arvieux, J.; Asaturyan, R.; Averett, T.; Bailey, S.L.; Batigne, G.; Beck, D.H.; Beise, E.J.; Benesch, J.; Bimbot, L.; Birchall, J.; Korsch, W.; Kox, S.; Kuhn, J.; Lachniet, J.; Lee, L.; Lenoble, J.; Liatard, E.; Liu, J.; Loupias, B.; G0 Collaboration; Lung, A.; MacLachlan, G.A.; Marchand, D.; Martin, J.W.; McFarlane, K.W.; McKee, D.W.; McKeown, R.D.; Merchez, F.; Mkrtchyan, H.; Moffit, B.; Morlet, M.; Nakagawa, I.; Nakahara, K.; Nakos, M.; Neveling, R.; Niccolai, S.; Ong, S.; Page, S.; Papavassiliou, V.; Pate, S.F.; Phillips, S.K.; Pitt, M.L.; Poelker, M.; Porcelli, T.A.; Quemener, G.; Quinn, B.; Ramsay, W.D.; Rauf, A.W.; Real, J.-S.; Roche, J.; Roos, P.; Rutledge, G.A.; Secrest, J.; Simicevic, N.; Smith, G.R.; Spayde, D.T.; Stepanyan, S.; Stutzman, M.; Sulkosky, V.; Tadevosyan, V.; Tieulent, R.; van de Wiele, J.; van Oers, W.; Voutier, E.; G0 Collaboration; Vulcan, W.; Warren, G.; Wells, S.P.; Williamson, S.E.; Wood, S.A.; Yan, C.; Yun, J.; Zeps, V.; Biselli, A.; Bosted, P.; Boukobza, E.; Breuer, H.; Carlini, R.; Carr, R.; Chant, N.; Chao, Y.-C.; Chattopadhyay, S.; Clark, R.; Covrig, S.; Cowley, A.; Dale, D.; Davis, C.; Falk, W.; Finn, J.M.; Forest, T.; Franklin, G.; Furget, C.; Gaskell, D.; Grames, J.; Griffioen, K.A.; Grimm, K.; Guillon, B.; Guler, H.; Hannelius, L.; Hasty, R.; Hawthorne Allen, A.; Horn, T.; Johnston, K.; Jones, M.; Kammel, P.; Kazimi, R.; King, P.M.; Kolarkar, A.; Korkmaz, E.We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12≤Q2≤1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.Item Parity Violation in Elastic Electron-Proton Scattering and the Proton's Strange Magnetic Form Factor(American Physical Society, 2000-02-07) Spayde, D.T.; Averett, T.; Barkhuff, D.; Beck, D.H.; Beise, E.J.; Benson, C.; Breuer, H.; Carr, R.; Covrig, S.; DelCorso, J.; Dodson, G.; Dow, K.; Eppstein, C.; Farkhondeh, M.; Filippone, B.W.; Frazier, P.; Hasty, R.; Ito, T.M.; Jones, C.E.; Korsch, W.; Kowalski, S.; Lee, P.; Maneva, E.; McCarty, K.; McKeown, R.D.; Mikell, J.; Mueller, B.; Naik, P.; Pitt, M.; Ritter, J.; Savu, V.; Sullivan, M.; Tieulent, R.; Tsentalovich, E.; Wells, S.P.; Yang, B.; Zwart, T.; SAMPLE CollaborationWe report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92±0.61±0.73ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.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 Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering(American Physical Society, 2007-07-31) Armstrong, D.S.; Arvieux, J.; Asaturyan, R.; Averett, T.; Bailey, S.L.; Batigne, G.; Beck, D.H.; Beise, E.J.; Benesch, J.; Bimbot, L.; Birchall, J.; Roche, J.; Roos, P.; Rutledge, G.A.; Secrest, J.; Simicevic, N.; Smith, G.R.; Spayde, D.T.; Stepanyan, S.; Stutzman, M.; Sulkosky, V.; Tadevosyan, V.; Tieulent, R.; Van de Wiele, J.; van Oers, W.T.H.; Voutier, E.; Vulcan, W.; Warren, G.; Wells, S.P.; Williamson, S.E.; Wood, S.A.; Yan, C.; Yun, J.; Zeps, V.; G0 Collaboration; Biselli, A.; Bosted, P.; Boukobza, E.; Breuer, H.; Carlini, R.; Carr, R.; Chant, N.; Chao, Y.-C.; Chattopadhyay, S.; Clark, R.; Covrig, S.; Cowley, A.; Dale, D.; Davis, C.; Falk, W.; Finn, J.M.; Forest, T.; Franklin, G.; Furget, C.; Gaskell, D.; Grames, J.; Griffioen, K.A.; Grimm, K.; Guillon, B.; Guler, H.; Hannelius, L.; Hasty, R.; Hawthorne Allen, A.; Horn, T.; Johnston, K.; Jones, M.; Kammel, P.; Kazimi, R.; King, P.M.; Kolarkar, A.; Korkmaz, E.; Korsch, W.; Kox, S.; Kuhn, J.; Lachniet, J.; Lee, L.; Lenoble, J.; Liatard, E.; Liu, J.; Loupias, B.; Lung, A.; Marchand, D.; Martin, J.W.; McFarlane, K.W.; McKee, D.W.; McKeown, R.D.; Merchez, F.; Mkrtchyan, H.; Moffit, B.; Morlet, M.; Nakagawa, I.; Nakahara, K.; Neveling, R.; Ong, S.; Page, S.; Papavassiliou, V.; Pate, S.F.; Phillips, S.K.; Pitt, M.L.; Poelker, M.; Porcelli, T.A.; Quéméner, G.; Quinn, B.; Ramsay, W.D.; Rauf, A.W.; Real, J.-S.We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. An provides a direct probe of the imaginary component of the 2γ exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.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 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 Coherent π0 photoproduction on the deuteron up to 4 GeV(1999-09) Meekins, D.G.; 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.; Bochna, C.; 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.; Markowitz, P.; McFarlane, K.W.; McKeown, R.D.; 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, D.; Reinhold, J.; Rutt, P.M; Salgado, C.W.; Savage, G.; Segel, R.E.; Simicevic, N.; Stoler, P.; Suleiman, R.; Tang, L.; Terburg, B.P.; van Westrum, D.; Vulcan, W.F.; Williamson, S.E.; Witkowski, M.T.; Wood, S.A.; Yan, C.; Zeidman, B.The differential cross section for 2H(γ,d)π0 has been measured at deuteron center-of-mass angles of 90° and 136°. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic ed scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions.Item Tensor polarization in elastic electron-deuteron scattering in the momentum transfer range 3.8≤Q≤4.6 fm-1(1994-05) Garçon, M.; 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.; Goloskie, R.; Hoibraten, S.; Jourdan, J.; Kowlaski, 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.; The, I.; Turchinetz, W.E.; Williamson, C.F.; Wilson, K.E.; Wood, S.A.; Zeigler, W.The tensor polarization of the recoil deuteron in elastic electron-deuteron scattering has been measured at the Bates Linear Accelerator Center at three values of four-momentum transfer Q=3.78, 4.22, and 4.62 fm-1, corresponding to incident electron energies of 653, 755, and 853 MeV. The scattered electrons and the recoil deuterons were detected in coincidence. The recoil deuterons were transported to a liquid hydrogen target to undergo a second scattering. The angular distribution of the d→-p scattering was measured using a polarimeter. The polarimeter was calibrated in an auxiliary experiment using a polarized deuteron beam at the Laboratoire National Saturne. A Monte Carlo procedure was used to generate interpolated calibration data because the energy spread in the deuteron energies in the Bates experiment spanned the range of deuteron energies in the calibration experiment. The extracted values of t20 are compared to predictions of different theoretical models of the electromagnetic form factors of the deuteron: nonrelativistic and relativistic nucleon-meson dynamics, Skyrme model, quark models, and perturbative quantum chromodynamics. Along with the world data the structure functions A(Q) and B(Q) are used to separate the charge monopole and charge quadrupole form factors of the deuteron. A node in the charge monopole form factor is observed at Q=4.39±0.16 fm-1.Item Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment(2010-01) Armstrong, D.S.; Arvieux, J.; Asaturyan, R.; Averett, T.; Bailey, S.L.; Batigne, G.; Beck, D.H.; Beise, E.J.; Benesch, J.; Bimbot, L.; Birchall, J.; Hannelius, L.; Hasty, R.; Hawthorne-Allen, A.; Horn, T.; Johnston, K.; Jones, M.; Kammel, P.; Kazimi, R.; King, P.M.; Kolarkar, A.; Korkmaz, E.; Korsch, W.; Kox, S.; Kuhn, J.; Lachniet, J.; Lee, L.; Lenoble, J.; Liatard, E.; Liu, J.; Loupias, B.; Lung, A.; MacLachlan, G.A.; Marchand, D.; Martin, J.W.; McFarlane, K.W.; McKee, D.W.; McKeown, R.D.; Merchez, F.; Mkrtchyan, H.; Moffit, B.; Morlet, M.; Nakagawa, I.; Nakahara, K.; Nakos, M.; Neveling, R.; Niccolai, S.; Ong, S.; Page, S.; Papavassiliou, V.; Pate, S.F.; Phillips, S.K.; Pitt, M.L.; Poelker, M.; Porcelli, T.A.; Quemener, G.; Quinn, B.; Ramsay, W.D.; Rauf, A.W.; Real, J.S.; Roche, J.; Roos, P.; Rutledge, G.A.; Secrest, J.; Simicevic, N.; Smith, G.R.; Spayde, D.T.; Stepanyan, S.; Stutzman, M.; Sulkosky, V.; Tadevosyan, V.; Tieulent, R.; van de Wiele, J.; van Oers, W.; Voutier, E.; Vulcan, W.; Warren, G.; Wells, S.P.; Williamson, S.E.; Wood, S.A.; Yan, C.; Yun, J.; Zeps, V.; Biselli, A.; Bosted, P.; Boukobza, E.; Breuer, H.; Carlini, R.; Carr, R.; Chant, N.; Chao, Y.C.; Chattopadhyay, S.; Clark, R.; Covrig, S.; Cowley, A.; Dale, D.; Davis, C.; Falk, W.; Finn, J.M.; Forest, T.; Franklin, G.; Furget, C.; Gaskell, D.; Grames, J.; Griffioen, K.A.; Grimm, K.; Guillon, B.; Guler, H.We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 ≤ Q2 ≤ 1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange quark contributions to the currents of the proton. The measurements were made at JLab using a toroidal spectrom- eter to detect the recoiling protons from a liquid hydrogen target. The results indicate non-zero, Q2 dependent, strange quark contributions and provide new information beyond that obtained in previous experiments.Item The Strange Quark Contribution to the Proton’s Magnetic Moment(2004-03) Spayde, D.T.; Averett, T.; Barkhuff, D.; Beck, D.H.; Beise, E.J.; Breuer, H.; Carr, R.; Covrig, S.; Dodson, G.; Dow, K.; Farkhondeh, M.; Filippone, B.W.; Franklin, W.; Hasty, R.; Ito, T.M.; Korsch, W.; Kowalski, S.; McKeown, R.D.; Mueller, B.; Pitt, M.L.; Ramsey-Musolf, M.J.; Ritter, J.; Tieulent, R.; Tsentalovich, E.; Wells, S.P.; Yang, B.; Zwart, T.We report a new determination of the strange quark contribution to the proton’s magnetic form factor at a four-momentum transfer Q2 = 0.1(GeV/c)2 from parity-violating e-p elastic scattering. The result uses a revised analysis of data from the SAMPLE experiment which was carried out at the MIT-Bates Laboratory. The data are combined with a calculation of the proton’s axial form factor GeA to determine the strange form factor GsM (Q2=0.1)=0.37±0.20±0.26±0.07. The extrapolation of GsM to its Q2 = 0 limit and comparison with calculations is also discussed.