Physics Research Works
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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 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 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 Measurement of the spin-dependent asymmetry in 3→(e→,e′) inelastic scattering at low energy transfer(1995-09) 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.; DeSchepper, D.; Dodson, G.; Dow, K.; Ent, R.; Farkhondeh, M.; Hansen, J.-O.; Korsch, W.; Kramer, L.H.; Lee, K.; Makins, N.C.R.; Milner, R.G.; Teiger, D.R.; Welch, T.P.; Candell, E.; Napolitano, J.; Tripp, C.; Wojtsekhowski, B.B.We present the results of a measurement of the spin-dependent asymmetry in 3→(e→,e′) inelastic scattering at kinematics on the low-energy transfer side of the quasielastic peak, including the region near the breakup threshold. Comparison with existing calculations based upon the plane wave impulse approximation shows significant deviation between the data and the model near the breakup threshold. Good agreement between data and theory is seen at higher energy transfer.Item Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized 3He(1994-08) Gao, A.; Arrington, J.; Beise, E.J.; Bray, B.; Carr, R.W.; Filippone, B.W.; Lung, A.; McKeown, R.D.; Mueller, B.; Pitt, M.L.; Jones, C.E.; DeSchepper, D.; Dodson, G.; Dow, K.; Ent, R.; Farkhondeh, M.; Hansen, J.-O.; Korsch, W.; Kramer, L.H.; Lee, K.; Makins, N.; Milner, R.G.; Teiger, D.R.; Welch, T.P.; Candell, E.; Napolitano, J.; Wojtsekhowski, B.B.; Tripp, C.; Lorenzon, W.We report a measurement of the asymmetry in spin-dependent quasielastic scattering of longitudinally polarized electrons from a polarized 3He target. The neutron magnetic form factor GMn has been extracted from the measured asymmetry based on recent PWIA calculations using spin-dependent spectral functions. Our determination of GMn at Q2=0.19 (GeV/c)2 agrees with the dipole parametrization. This experiment represents the first measurement of the neutron magnetic form factor using spin-dependent electron scattering.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.Item Parity-violating Electron Deuteron Scattering and the Proton’s Neutral Weak Axial Vector Form Factor(2004-03) Ito, T.M.; Averett, T.; Barkhuff, D.; Batigne, G.; Beck, D.H.; Beise, E.J.; Blake, A.; Breuer, H.; Carr, R.; Clasie, B.; Covrig, S.; Danagoulian, A.; Dodson, G.; Dow, K.; Dutta, D.; Farkhondeh, M.; Filippone, B.W.; Franklin, W.; Furget, C.; Gao, H.; Gao, J.; Gustafsson, K.; Hannelius, L.; Hasty, R.; Hawthorne-Allen, A.M.; Herda, M.C.; Jones, C.E.; King, P.; Korsch, W.; Kowalski, S.; Kox, S.; Kramer, K.; Lee, P.; Liu, J.; Martin, J.W.; McKeown, R.D.; Mueller, B.; Pitt, M.L.; Plaster, B.; Quemener, G.; Real, J. S.; Ritter, J.; Roche, J.; Savu, V.; Schiavilla, R.; Seely, J.; Spayde, D.; Suleiman, R.; Taylor, S.; Tieulent, R.; Tipton, B.; Tsentalovich, E.; Wells, S.P.; Yang, B.; Yuan, J.; Yun, J.; Zwart, T.; SAMPLE CollaborationWe report on a new measurement of the parity-violating asymmetry in quasielastic electron scat- tering from the deuteron at backward angles at Q2 = 0.038 (GeV/c)2. This quantity provides a de- termination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A = −3.51 ± 0.57 (stat) ± 0.58 (sys) ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2 = 0.091 (GeV/c)2, which are also consistent with theoretical predictions.