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23 results on '"Paschke KD"'

1. Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from C12 and Al27

Author

Androić, D, Armstrong, DS, Asaturyan, A, Bartlett, K, Beminiwattha, RS, Benesch, J, Benmokhtar, F, Birchall, J, Carlini, RD, Christy, ME, Cornejo, JC, Dusa, S Covrig, Dalton, MM, Davis, CA, Deconinck, W, Dowd, JF, Dunne, JA, Dutta, D, Duvall, WS, Elaasar, M, Falk, WR, Finn, JM, Forest, T, Gal, C, Gaskell, D, Gericke, MTW, Gray, VM, Guo, F, Hoskins, JR, Jones, DC, Kargiantoulakis, M, King, PM, Korkmaz, E, Kowalski, S, Leacock, J, Leckey, JP, Lee, AR, Lee, JH, Lee, L, MacEwan, S, Mack, D, Magee, JA, Mahurin, R, Mammei, J, Martin, JW, McHugh, MJ, Meekins, D, Mesick, KE, Michaels, R, Mkrtchyan, A, Mkrtchyan, H, Narayan, A, Ndukum, LZ, Nelyubin, V, Nuruzzaman, van Oers, WTH, Owen, VF, Page, SA, Pan, J, Paschke, KD, Phillips, SK, Pitt, ML, Radloff, RW, Rajotte, JF, Ramsay, WD, Roche, J, Sawatzky, B, Seva, T, Shabestari, MH, Silwal, R, Simicevic, N, Smith, GR, Solvignon, P, Spayde, DT, Subedi, A, Subedi, R, Suleiman, R, Tadevosyan, V, Tobias, WA, Tvaskis, V, Waidyawansa, B, Wang, P, Wells, SP, Wood, SA, Zang, P, and Zhamkochyan, S

Subjects
Clinical Research, nucl-ex
Abstract

We report measurements of the parity-conserving beam-normal single-spinelastic scattering asymmetries $B_n$ on $^{12}$C and $^{27}$Al, obtained withan electron beam polarized transverse to its momentum direction. Thesemeasurements add an additional kinematic point to a series of previousmeasurements of $B_n$ on $^{12}$C and provide a first measurement on $^{27}$Al.The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energyof 1.158 GeV. The average lab scattering angle for both targets was 7.7degrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561GeV). The asymmetries are $B_n$ = -10.68 $\pm$ 0.90 stat) $\pm$ 0.57 (syst) ppmfor $^{12}$C and $B_n$ = -12.16 $\pm$ 0.58 (stat) $\pm$ 0.62 (syst) ppm for$^{27}$Al. The results are consistent with theoretical predictions, and arecompared to existing data. When scaled by Z/A, the Q-dependence of all thefar-forward angle (theta < 10 degrees) data from $^{1}$H to $^{27}$Al can bedescribed by the same slope out to $Q \approx 0.35$ GeV. Larger-angle data fromother experiments in the same Q range are consistent with a slope about twiceas steep.

Published
2021

2. Measurement of the Beam-Normal Single-Spin Asymmetry for Elastic Electron Scattering from $^{12}$C and $^{27}$Al

Author

QWeak Collaboration, Androic, D, Armstrong, DS, Asaturyan, A, Bartlett, K, Beminiwattha, RS, Benesch, J, Benmokhtar, F, Birchall, J, Carlini, RD, Christy, ME, Cornejo, JC, Dusa, S Covrig, Dalton, MM, Davis, CA, Deconinck, W, Dowd, JF, Dunne, JA, Dutta, D, Duvall, WS, Elassar, M, Falk, WR, Finn, JM, Forest, T, Gal, C, Gaskell, D, Gericke, MTW, Gray, VM, Guo, F, Hoskins, JR, Jones, DC, Kargiantoulakis, M, King, PM, Korkmaz, E, Kowalski, S, Leacock, J, Leckey, JP, Lee, AR, Lee, JH, Lee, L, MacEwan, S, Mack, D, Magee, JA, Mahurin, R, Mammei, J, Martin, JW, McHugh, MJ, Meekins, D, Mesick, KE, Michaels, R, Mkrtchyan, A, Mkrtchyan, H, Narayan, A, Ndukum, LZ, Nuruzzaman, Nelyubin, V, van Oers, WTH, Owen, VF, Page, SA, Pan, J, Paschke, KD, Phillips, SK, Pitt, ML, Radloff, RW, Rajotte, JF, Ramsay, WD, Roche, J, Sawatzky, B, Seva, T, Shabestari, MH, Silwal, R, Simicevic, N, Smith, GR, Solvignon, P, Spayde, DT, Subedi, A, Subedi, R, Tadevosyan, V, Tobias, WA, Waidyawansa, B, Wang, P, Wells, SP, Wood, SA, Zang, P, and Zhamkochyan, S

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Particle and High Energy Physics, nucl-ex, Nuclear and plasma physics
Abstract

We report measurements of the parity-conserving beam-normal single-spinelastic scattering asymmetries $B_n$ on $^{12}$C and $^{27}$Al, obtained withan electron beam polarized transverse to its momentum direction. Thesemeasurements add an additional kinematic point to a series of previousmeasurements of $B_n$ on $^{12}$C and provide a first measurement on $^{27}$Al.The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energyof 1.158 GeV. The average lab scattering angle for both targets was 7.7degrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561GeV). The asymmetries are $B_n$ = -10.68 $\pm$ 0.90 stat) $\pm$ 0.57 (syst) ppmfor $^{12}$C and $B_n$ = -12.16 $\pm$ 0.58 (stat) $\pm$ 0.62 (syst) ppm for$^{27}$Al. The results are consistent with theoretical predictions, and arecompared to existing data. When scaled by Z/A, the Q-dependence of all thefar-forward angle (theta < 10 degrees) data from $^{1}$H to $^{27}$Al can bedescribed by the same slope out to $Q \approx 0.35$ GeV. Larger-angle data fromother experiments in the same Q range are consistent with a slope about twiceas steep.

Published
2021

3. Measurement of the Neutron Radius of Pb-208 through Parity Violation in Electron Scattering

Author

Abrahamyan, S, Ahmed, Z, Albataineh, H, Aniol, K, Armstrong, Ds, Armstrong, W, Averett, T, Babineau, B, Barbieri, A, Bellini, Vincenzo, Beminiwattha, R, Benesch, J, Benmokhtar, F, Bielarski, T, Boeglin, W, Camsonne, A, Canan, M, Carter, P, Cates, Gd, Chen, C, Chen, Jp, Hen, O, Cusanno, F, Dalton, Mm, De, Le, R, de Jager, K, Deconinck, W, Decowski, P, Deng, X, Deur, A, Dutta, D, Etile, A, Flay, D, Franklin, Gb, Friend, M, Frullani, S, Fuchey, E, Garibaldi, F, Gasser, E, Gilman, R, Giusa, A, Glamazdin, A, Gomez, J, Grames, J, Gu, C, Hansen, O, Hansknecht, J, Higinbotham, Dw, Holmes, Rs, Holmstrom, T, Horowitz, Cj, Hoskins, J, Huang, J, Hyde, Ce, Itard, F, Jen, Cm, Jensen, E, Jin, G, Johnston, S, Kelleher, A, Kliakhandler, K, King, Pm, Kowalski, S, Kumar, Ks, Leacock, J, Leckey, J, Lee, Jh, Lerose, Jj, Lindgren, R, Liyanage, N, Lubinsky, N, Mammei, J, Mammoliti, Francesco, Margaziotis, Dj, Markowitz, P, Mccreary, A, Mcnulty, D, Mercado, L, Meziani, Ze, Michaels, Rw, Mihovilovic, M, Muangma, N, Munoz Camacho, C, Nanda, S, Nelyubin, V, Nuruzzaman, N, Oh, Y, Palmer, A, Parno, D, Paschke, Kd, Phillips, Sk, Poelker, B, Pomatsalyuk, R, Posik, M, Puckett, Ajr, Quinn, B, Rakhman, A, Reimer, Pe, Riordan, S, Rogan, P, Ron, G, Russo, Giuseppe, Saenboonruang, K, Saha, A, Sawatzky, B, Shahinyan, A, Silwal, R, Sirca, S, Slifer, K, Solvignon, P, Souder, Pa, Sperduto, Ml, Subedi, R, Suleiman, R, Sulkosky, V, Sutera, CONCETTA MARIA, Tobias, Wa, Troth, W, Urciuoli, Gm, Waidyawansa, B, Wang, D, Wexler, J, Wilson, R, Wojtsekhowski, B, Yan, X, Yao, H, Ye, Y, Ye, Z, Yim, V, Zana, L, Zhan, X, Zhang, J, Zhang, Y, Zheng, X, and PREX Collaboration, Zhu P.

Subjects
ELECTRON-SCATTERING, NUCLEI, DENSITIES
Published
2012

4. Constraints on the nucleon strange form factors at Q(2)similar to 0.1 GeV2

Author

Aniol, KA, Armstrong, DS, Averett, T, Benaoum, H, Bertin, PY, Burtin, E, Cahoon, J, Gates, GD, Chang, CC, Chao, YC, Chen, JP, Choi, SH, Chudakov, E, Craver, B, Cusanno, F, Decowski, P, Deepa, D, Ferdi, C, Feuerbach, RJ, Finn, JM, Frullani, S, Fuoti, K, Garibaldi, F, Gilman, R, Glamazdin, A, Gorbenko, V, Grames, JM, Hansknecht, J, Higinbotham, DW, Holmes, R, Holmstrom, T, Humensky, TB, Ibrahim, H, de Jager, CW, Jiang, X, Kaufman, LJ, Kelleher, A, Kolarkar, A, Kowalski, S, Kumar, KS, Lambert, D, LaViolette, P, LeRose, J, Lhuillier, D, Liyanage, N, Margaziotis, DJ, Mazouz, M, McCormick, K, Meekins, DG, Meziani, ZE, Michaels, R, Moffit, B, Monaghan, P, Munoz-Camacho, C, Nanda, S, Nelyubin, V, Neyret, D, Paschke, KD, Poelker, M, Pomatsalyuk, R, Qiang, Y, Reitz, B, Roche, J, Saha, A, Singh, J, Snyder, R, Souder, PA, Stutzman, M, Subedi, R, Suleiman, R, Sulkosky, V, Tobias, WA, Urciuoli, GM, Vacheret, A, Voutier, E, Wang, K, Wilson, R, Wojtsekhowski, B, and Zheng, X

Published
2006

5. Parity-violating electron scattering from 4He and the strange electric form factor of the nucleon

Author

Aniol, KA, Armstrong, DS, Averett, T, Benaoum, H, Bertin, PY, Burtin, E, Cahoon, J, Cates, GD, Chang, CC, Chao, YC, Chen, JP, Choi, S, Chudakov, E, Craver, B, Cusanno, F, Decowski, P, Deepa, D, Ferdi, C, Feuerbach, RJ, Finn, JM, Frullani, S, Fuoti, K, Garibaldi, F, Gilman, R, Glamazdin, A, Gorbenko, V, Grames, JM, Hansknecht, J, Higinbotham, DW, Holmes, R, Holmstrom, T, Humensky, TB, Ibrahim, H, de Jager, CW, Jiang, X, Kaufman, LJ, Kelleher, A, Kolarkar, A, Kowalski, S, Kumar, KS, Lambert, D, LaViolette, P, LeRose, J, Lhuillier, D, Liyanage, N, Margaziotis, DJ, Mazouz, M, McCormick, K, Meekins, DG, Meziani, ZE, Michaels, R, Moffit, B, Monaghan, P, Munoz-Camacho, C, Nanda, S, Nelyubin, V, Neyret, D, Paschke, KD, Poelker, M, Pomatsalyuk, R, Qiang, Y, Reitz, B, Roche, J, Saha, A, Singh, J, Snyder, R, Souder, PA, Subedi, R, Suleiman, R, Sulkosky, V, Tobias, WA, Urciuoli, GM, Vacheret, A, Voutier, E, Wang, K, Wilson, R, Wojtsekhowski, B, and Zheng, X

Subjects
High Energy Physics::Experiment, Nuclear Experiment
Abstract

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 4He at an average scattering angle = 5.7 degrees and a four-momentum transfer Q2 = 0.091 GeV2 . From these data, for the first time, the strange electric form factor of the nucleon G(E)s can be isolated. The measured asymmetry of A(PV) = (6.72 +/- 0.84(stat) +/- 0.21(syst) x 10(-6) yields a value of G(E)s = -0.038 +/- 0.042(stat) +/- 0.010(syst), consistent with zero.

Published
2005

6. Precision Determination of the Neutral Weak Form Factor of ^{48}Ca.

Author

Adhikari D, Albataineh H, Androic D, Aniol KA, Armstrong DS, Averett T, Ayerbe Gayoso C, Barcus SK, Bellini V, Beminiwattha RS, Benesch JF, Bhatt H, Bhatta Pathak D, Bhetuwal D, Blaikie B, Boyd J, Campagna Q, Camsonne A, Cates GD, Chen Y, Clarke C, Cornejo JC, Covrig Dusa S, Dalton MM, Datta P, Deshpande A, Dutta D, Feldman C, Fuchey E, Gal C, Gaskell D, Gautam T, Gericke M, Ghosh C, Halilovic I, Hansen JO, Hassan O, Hauenstein F, Henry W, Horowitz CJ, Jantzi C, Jian S, Johnston S, Jones DC, Kakkar S, Katugampola S, Keppel C, King PM, King DE, Kumar KS, Kutz T, Lashley-Colthirst N, Leverick G, Liu H, Liyanage N, Mammei J, Mammei R, McCaughan M, McNulty D, Meekins D, Metts C, Michaels R, Mihovilovic M, Mondal MM, Napolitano J, Narayan A, Nikolaev D, Owen V, Palatchi C, Pan J, Pandey B, Park S, Paschke KD, Petrusky M, Pitt ML, Premathilake S, Quinn B, Radloff R, Rahman S, Rashad MNH, Rathnayake A, Reed BT, Reimer PE, Richards R, Riordan S, Roblin YR, Seeds S, Shahinyan A, Souder P, Thiel M, Tian Y, Urciuoli GM, Wertz EW, Wojtsekhowski B, Yale B, Ye T, Yoon A, Xiong W, Zec A, Zhang W, Zhang J, and Zheng X

Abstract

We report a precise measurement of the parity-violating (PV) asymmetry A&#95;{PV} in the elastic scattering of longitudinally polarized electrons from ^{48}Ca. We measure A&#95;{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor F&#95;{W}(q=0.8733  fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor F&#95;{ch}-F&#95;{W}=0.0277±0.0055. The resulting neutron skin thickness R&#95;{n}-R&#95;{p}=0.121±0.026(exp)±0.024(model)  fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.

Published
2022
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7. New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering over a Range of Spin-0 Nuclei.

Author

Adhikari D, Albataineh H, Androic D, Aniol K, Armstrong DS, Averett T, Ayerbe Gayoso C, Barcus S, Bellini V, Beminiwattha RS, Benesch JF, Bhatt H, Bhatta Pathak D, Bhetuwal D, Blaikie B, Boyd J, Campagna Q, Camsonne A, Cates GD, Chen Y, Clarke C, Cornejo JC, Covrig Dusa S, Dalton MM, Datta P, Deshpande A, Dutta D, Feldman C, Fuchey E, Gal C, Gaskell D, Gautam T, Gericke M, Ghosh C, Halilovic I, Hansen JO, Hauenstein F, Henry W, Horowitz CJ, Jantzi C, Jian S, Johnston S, Jones DC, Karki B, Kakkar S, Katugampola S, Keppel CE, King PM, King DE, Knauss M, Kumar KS, Kutz T, Lashley-Colthirst N, Leverick G, Liu H, Liyange N, Malace S, Mammei J, Mammei R, McCaughan M, McNulty D, Meekins D, Metts C, Michaels R, Mihovilovic M, Mondal MM, Napolitano J, Nikolaev D, Rashad MNH, Owen V, Palatchi C, Pan J, Pandey B, Park S, Paschke KD, Petrusky M, Pitt ML, Premathilake S, Puckett AJR, Quinn B, Radloff R, Rahman S, Rathnayake A, Reed BT, Reimer PE, Richards R, Riordan S, Roblin Y, Seeds S, Shahinyan A, Souder PA, Tang L, Thiel M, Tian Y, Urciuoli GM, Wertz EW, Wojtsekhowski B, Xiong W, Yale B, Ye T, Zec A, Zhang W, Zhang J, and Zheng X

Abstract

We report precision determinations of the beam-normal single spin asymmetries (A&#95;{n}) in the elastic scattering of 0.95 and 2.18 GeV electrons off ^{12}C, ^{40}Ca, ^{48}Ca, and ^{208}Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of A&#95;{n} for ^{40}Ca and ^{48}Ca are found to be similar to that of ^{12}C, consistent with expectations and thus demonstrating the validity of theoretical calculations for nuclei with Z≤20. We also report A&#95;{n} for ^{208}Pb at two new momentum transfers (Q^{2}) extending the previous measurement. Our new data confirm the surprising result previously reported, with all three data points showing significant disagreement with the results from the Z≤20 nuclei. These data confirm our basic understanding of the underlying dynamics that govern A&#95;{n} for nuclei containing ≲50 nucleons, but point to the need for further investigation to understand the unusual A&#95;{n} behavior discovered for scattering off ^{208}Pb.

Published
2022
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8. Determination of the ^{27}Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement.

Author

Androić D, Armstrong DS, Bartlett K, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cornejo JC, Covrig Dusa S, Dalton MM, Davis CA, Deconinck W, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gal C, Gaskell D, Gericke MTW, Gray VM, Grimm K, Guo F, Hoskins JR, Jones DC, Jones MK, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mesick KE, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Narayan A, Ndukum LZ, Nelyubin V, Nuruzzaman, van Oers WTH, Owen VF, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Radloff RW, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Zang P, Zhamkochyan S, Christy ME, Horowitz CJ, Fattoyev FJ, and Lin Z

Abstract

We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A&#95;{PV}=2.16±0.11(stat)±0.16(syst)  ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010  GeV^{2}, ⟨θ&#95;{lab}⟩=7.61°±0.02°, and ⟨E&#95;{lab}⟩=1.157  GeV with the Q&#95;{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R&#95;{n}=2.89±0.12  fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R&#95;{n}-R&#95;{p}=-0.04±0.12  fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R&#95;{w}=3.00±0.15  fm, and the weak skin thickness R&#95;{wk}-R&#95;{ch}=-0.04±0.15  fm. The weak form factor at this Q^{2} is F&#95;{wk}=0.39±0.04.

Published
2022
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9. Accurate Determination of the Neutron Skin Thickness of ^{208}Pb through Parity-Violation in Electron Scattering.

Author

Adhikari D, Albataineh H, Androic D, Aniol K, Armstrong DS, Averett T, Ayerbe Gayoso C, Barcus S, Bellini V, Beminiwattha RS, Benesch JF, Bhatt H, Bhatta Pathak D, Bhetuwal D, Blaikie B, Campagna Q, Camsonne A, Cates GD, Chen Y, Clarke C, Cornejo JC, Covrig Dusa S, Datta P, Deshpande A, Dutta D, Feldman C, Fuchey E, Gal C, Gaskell D, Gautam T, Gericke M, Ghosh C, Halilovic I, Hansen JO, Hauenstein F, Henry W, Horowitz CJ, Jantzi C, Jian S, Johnston S, Jones DC, Karki B, Katugampola S, Keppel C, King PM, King DE, Knauss M, Kumar KS, Kutz T, Lashley-Colthirst N, Leverick G, Liu H, Liyange N, Malace S, Mammei R, Mammei J, McCaughan M, McNulty D, Meekins D, Metts C, Michaels R, Mondal MM, Napolitano J, Narayan A, Nikolaev D, Rashad MNH, Owen V, Palatchi C, Pan J, Pandey B, Park S, Paschke KD, Petrusky M, Pitt ML, Premathilake S, Puckett AJR, Quinn B, Radloff R, Rahman S, Rathnayake A, Reed BT, Reimer PE, Richards R, Riordan S, Roblin Y, Seeds S, Shahinyan A, Souder P, Tang L, Thiel M, Tian Y, Urciuoli GM, Wertz EW, Wojtsekhowski B, Yale B, Ye T, Yoon A, Zec A, Zhang W, Zhang J, and Zheng X

Abstract

We report a precision measurement of the parity-violating asymmetry A&#95;{PV} in the elastic scattering of longitudinally polarized electrons from ^{208}Pb. We measure A&#95;{PV}=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor F&#95;{W}(Q^{2}=0.00616  GeV^{2})=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is R&#95;{n}-R&#95;{p}=0.283±0.071  fm. The result also yields the first significant direct measurement of the interior weak density of ^{208}Pb: ρ&#95;{W}^{0}=-0.0796±0.0036(exp)±0.0013(theo)  fm^{-3} leading to the interior baryon density ρ&#95;{b}^{0}=0.1480±0.0036(exp)±0.0013(theo)  fm^{-3}. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.

Published
2021
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10. Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering.

Author

Androić D, Armstrong DS, Asaturyan A, Bartlett K, Beaufait J, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cornejo JC, Dusa SC, Dalton MM, Davis CA, Deconinck W, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gal C, Gaskell D, Gericke MTW, Grames J, Gray VM, Grimm K, Guo F, Hoskins JR, Jones D, Jones MK, Jones RT, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey JP, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mei J, Mesick KE, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Narayan A, Ndukum LZ, Nelyubin V, Nuruzzaman, van Oers WTH, Owen VF, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Radloff RW, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Zang P, and Zhamkochyan S

Abstract

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ&#95;{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B&#95;{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ&#95;{lab}→0) where they should be most reliable.

Published
2020
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11. First Measurement of the Q^{2} Dependence of the Beam-Normal Single Spin Asymmetry for Elastic Scattering off Carbon.

Author

Esser A, Thiel M, Achenbach P, Aulenbacher K, Baunack S, Beričič J, Bosnar D, Correa L, Dehn M, Distler MO, Fonvieille H, Friščić I, Gorchtein M, Heidrich S, Herrmann P, Hoek M, Kegel S, Kohl Y, Kolar T, Kreidel HJ, Maas FE, Merkel H, Mihovilovič M, Müller J, Müller U, Nillius F, Palatchi C, Paschke KD, Pochodzalla J, Schlimme BS, Schoth M, Schulz F, Širca S, Spruck B, Štajner S, Tioukine V, Tyukin A, Weber A, and Sfienti C

Abstract

We report on the first Q^{2}-dependent measurement of the beam-normal single spin asymmetry A&#95;{n} in the elastic scattering of 570 MeV vertically polarized electrons off ^{12}C. We cover the Q^{2} range between 0.02 and 0.05  GeV^{2}/c^{2} and determine A&#95;{n} at four different Q^{2} values. The experimental results are compared to a theoretical calculation that relates A&#95;{n} to the imaginary part of the two-photon exchange amplitude. The result emphasizes that the Q^{2} behavior of A&#95;{n} given by the ratio of the Compton to charge form factors cannot be treated independently of the target nucleus.

Published
2018
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12. First determination of the weak charge of the proton.

Author

Androic D, Armstrong DS, Asaturyan A, Averett T, Balewski J, Beaufait J, Beminiwattha RS, Benesch J, Benmokhtar F, Birchall J, Carlini RD, Cates GD, Cornejo JC, Covrig S, Dalton MM, Davis CA, Deconinck W, Diefenbach J, Dowd JF, Dunne JA, Dutta D, Duvall WS, Elaasar M, Falk WR, Finn JM, Forest T, Gaskell D, Gericke MT, Grames J, Gray VM, Grimm K, Guo F, Hoskins JR, Johnston K, Jones D, Jones M, Jones R, Kargiantoulakis M, King PM, Korkmaz E, Kowalski S, Leacock J, Leckey J, Lee AR, Lee JH, Lee L, MacEwan S, Mack D, Magee JA, Mahurin R, Mammei J, Martin JW, McHugh MJ, Meekins D, Mei J, Michaels R, Micherdzinska A, Mkrtchyan A, Mkrtchyan H, Morgan N, Myers KE, Narayan A, Ndukum LZ, Nelyubin V, Nuruzzaman, van Oers WT, Opper AK, Page SA, Pan J, Paschke KD, Phillips SK, Pitt ML, Poelker M, Rajotte JF, Ramsay WD, Roche J, Sawatzky B, Seva T, Shabestari MH, Silwal R, Simicevic N, Smith GR, Solvignon P, Spayde DT, Subedi A, Subedi R, Suleiman R, Tadevosyan V, Tobias WA, Tvaskis V, Waidyawansa B, Wang P, Wells SP, Wood SA, Yang S, Young RD, and Zhamkochyan S

Abstract

The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.

Published
2013
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13. Measurements of parity-violating asymmetries in electron-deuteron scattering in the nucleon resonance region.

Author

Wang D, Pan K, Subedi R, Deng X, Ahmed Z, Allada K, Aniol KA, Armstrong DS, Arrington J, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Camsonne A, Canan M, Cates GD, Chen JP, Chudakov E, Cisbani E, Dalton MM, de Jager CW, De Leo R, Deconinck W, Deur A, Dutta C, El Fassi L, Flay D, Franklin GB, Friend M, Frullani S, Garibaldi F, Giusa A, Glamazdin A, Golge S, Grimm K, Hafidi K, Hansen O, Higinbotham DW, Holmes R, Holmstrom T, Holt RJ, Huang J, Hyde CE, Jen CM, Jones D, Kang H, King P, Kowalski S, Kumar KS, Lee JH, LeRose JJ, Liyanage N, Long E, McNulty D, Margaziotis DJ, Meddi F, Meekins DG, Mercado L, Meziani ZE, Michaels R, Mihovilovic M, Muangma N, Myers KE, Nanda S, Narayan A, Nelyubin V, Nuruzzaman, Oh Y, Parno D, Paschke KD, Phillips SK, Qian X, Qiang Y, Quinn B, Rakhman A, Reimer PE, Rider K, Riordan S, Roche J, Rubin J, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Souder PA, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Urciuoli GM, Waidyawansa B, Wojtsekhowski B, Ye L, Zhao B, and Zheng X

Abstract

We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.

Published
2013
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14. Measurement of the neutron radius of 208Pb through parity violation in electron scattering.

Author

Abrahamyan S, Ahmed Z, Albataineh H, Aniol K, Armstrong DS, Armstrong W, Averett T, Babineau B, Barbieri A, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Bielarski T, Boeglin W, Camsonne A, Canan M, Carter P, Cates GD, Chen C, Chen JP, Hen O, Cusanno F, Dalton MM, De Leo R, de Jager K, Deconinck W, Decowski P, Deng X, Deur A, Dutta D, Etile A, Flay D, Franklin GB, Friend M, Frullani S, Fuchey E, Garibaldi F, Gasser E, Gilman R, Giusa A, Glamazdin A, Gomez J, Grames J, Gu C, Hansen O, Hansknecht J, Higinbotham DW, Holmes RS, Holmstrom T, Horowitz CJ, Hoskins J, Huang J, Hyde CE, Itard F, Jen CM, Jensen E, Jin G, Johnston S, Kelleher A, Kliakhandler K, King PM, Kowalski S, Kumar KS, Leacock J, Leckey J 4th, Lee JH, LeRose JJ, Lindgren R, Liyanage N, Lubinsky N, Mammei J, Mammoliti F, Margaziotis DJ, Markowitz P, McCreary A, McNulty D, Mercado L, Meziani ZE, Michaels RW, Mihovilovic M, Muangma N, Muñoz-Camacho C, Nanda S, Nelyubin V, Nuruzzaman N, Oh Y, Palmer A, Parno D, Paschke KD, Phillips SK, Poelker B, Pomatsalyuk R, Posik M, Puckett AJ, Quinn B, Rakhman A, Reimer PE, Riordan S, Rogan P, Ron G, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Slifer K, Solvignon P, Souder PA, Sperduto ML, Subedi R, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Troth W, Urciuoli GM, Waidyawansa B, Wang D, Wexler J, Wilson R, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yim V, Zana L, Zhan X, Zhang J, Zhang Y, Zheng X, and Zhu P

Abstract

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

Published
2012
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15. New precision limit on the strange vector form factors of the proton.

Author

Ahmed Z, Allada K, Aniol KA, Armstrong DS, Arrington J, Baturin P, Bellini V, Benesch J, Beminiwattha R, Benmokhtar F, Canan M, Camsonne A, Cates GD, Chen JP, Chudakov E, Cisbani E, Dalton MM, de Jager CW, De Leo R, Deconinck W, Decowski P, Deng X, Deur A, Dutta C, Franklin GB, Friend M, Frullani S, Garibaldi F, Giusa A, Glamazdin A, Golge S, Grimm K, Hansen O, Higinbotham DW, Holmes R, Holmstrom T, Huang J, Huang M, Hyde CE, Jen CM, Jin G, Jones D, Kang H, King P, Kowalski S, Kumar KS, Lee JH, LeRose JJ, Liyanage N, Long E, McNulty D, Margaziotis D, Meddi F, Meekins DG, Mercado L, Meziani ZE, Michaels R, Muñoz-Camacho C, Mihovilovic M, Muangma N, Myers KE, Nanda S, Narayan A, Nelyubin V, Nuruzzaman, Oh Y, Pan K, Parno D, Paschke KD, Phillips SK, Qian X, Qiang Y, Quinn B, Rakhman A, Reimer PE, Rider K, Riordan S, Roche J, Rubin J, Russo G, Saenboonruang K, Saha A, Sawatzky B, Silwal R, Sirca S, Souder PA, Sperduto M, Subedi R, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Urciuoli GM, Waidyawansa B, Wang D, Wexler J, Wilson R, Wojtsekhowski B, Zhan X, Yan X, Yao H, Ye L, Zhao B, and Zheng X

Abstract

The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624  GeV2 and beam energy E(b) = 3.48  GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.

Published
2012
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16. High-resolution spectroscopy of Lambda16N by electroproduction.

Author

Cusanno F, Urciuoli GM, Acha A, Ambrozewicz P, Aniol KA, Baturin P, Bertin PY, Benaoum H, Blomqvist KI, Boeglin WU, Breuer H, Brindza P, Bydzovský P, Camsonne A, Chang CC, Chen JP, Choi S, Chudakov EA, Cisbani E, Colilli S, Coman L, Craver BJ, De Cataldo G, de Jager CW, De Leo R, Deur AP, Ferdi C, Feuerbach RJ, Folts E, Fratoni R, Frullani S, Garibaldi F, Gayou O, Giuliani F, Gomez J, Gricia M, Hansen JO, Hayes D, Higinbotham DW, Holmstrom TK, Hyde CE, Ibrahim HF, Iodice M, Jiang X, Kaufman LJ, Kino K, Kross B, Lagamba L, LeRose JJ, Lindgren RA, Lucentini M, Margaziotis DJ, Markowitz P, Marrone S, Meziani ZE, McCormick K, Michaels RW, Millener DJ, Miyoshi T, Moffit B, Monaghan PA, Moteabbed M, Muñoz Camacho C, Nanda S, Nappi E, Nelyubin VV, Norum BE, Okasyasu Y, Paschke KD, Perdrisat CF, Piasetzky E, Punjabi VA, Qiang Y, Raue B, Reimer PE, Reinhold J, Reitz B, Roche RE, Rodriguez VM, Saha A, Santavenere F, Sarty AJ, Segal J, Shahinyan A, Singh J, Sirca S, Snyder R, Solvignon PH, Sotona M, Subedi R, Sulkosky VA, Suzuki T, Ueno H, Ulmer PE, Veneroni P, Voutier E, Wojtsekhowski BB, Zheng X, and Zorn C

Abstract

An experimental study of the (16)O(e,e'K(+))(Lambda)(16)N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e'K(+))Lambda, Sigma(0) exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76+/-0.16 MeV was obtained for (Lambda)(16)N with better precision than previous measurements on the mirror hypernucleus (Lambda)(16)O. Precise energies have been determined for peaks arising from a Lambda in s and p orbits coupled to the p(1/2) and p(3/2) hole states of the (15)N core nucleus.

Published
2009
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17. High resolution spectroscopy of (lambda)(12)B by electroproduction.

Author

Iodice M, Cusanno F, Acha A, Ambrozewicz P, Aniol KA, Baturin P, Bertin PY, Benaoum H, Blomqvist KI, Boeglin WU, Breuer H, Brindza P, Bydzovský P, Camsonne A, Chang CC, Chen JP, Choi S, Chudakov EA, Cisbani E, Colilli S, Coman L, Craver BJ, De Cataldo G, de Jager CW, De Leo R, Deur AP, Ferdi C, Feuerbach RJ, Folts E, Fratoni R, Frullani S, Garibaldi F, Gayou O, Giulani F, Gomez J, Gricia M, Hansen JO, Hayes D, Higinbotham DW, Holmstrom TK, Hyde CE, Ibrahim HF, Jiang X, Kaufman LJ, Kino K, Kross B, Lagamba L, LeRose JJ, Lindgren RA, Lucentini M, Margaziotis DJ, Markowitz P, Marrone S, Meziani ZE, McCormick K, Michaels RW, Millener DJ, Miyoshi T, Moffit B, Monaghan PA, Moteabbed M, Muñoz Camacho C, Nanda S, Nappi E, Nelyubin VV, Norum BE, Okasyasu Y, Paschke KD, Perdrisat CF, Piasetzky E, Punjabi VA, Qiang Y, Raue B, Reimer PE, Reinhold J, Reitz B, Roche RE, Rodriguez VM, Saha A, Santavenere F, Sarty AJ, Segal J, Shahinyan A, Singh J, Sirca S, Snyder R, Solvignon PH, Sotona M, Subedi R, Sulkosky VA, Suzuki T, Ueno H, Ulmer PE, Urciuoli GM, Veneroni P, Voutier E, Wojtsekhowski BB, Ye Y, Zheng X, Zhou S, and Zorn C

Abstract

An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a 12C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed (Lambda)(12)B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave Lambda peak and the 11 MeV p-wave Lambda peak.

Published
2007
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18. Recoil-proton polarization in high-energy deuteron photodisintegration with circularly polarized photons.

Author

Jiang X, Arrington J, Benmokhtar F, Camsonne A, Chen JP, Choi S, Chudakov E, Cusanno F, Deur A, Dutta D, Garibaldi F, Gaskell D, Gayou O, Gilman R, Glashauser C, Hamilton D, Hansen O, Higinbotham DW, Holt RJ, de Jager CW, Jones MK, Kaufman LJ, Kinney ER, Kramer K, Lagamba L, de Leo R, Lerose J, Lhuillier D, Lindgren R, Liyanage N, McCormick K, Meziani ZE, Michaels R, Moffit B, Monaghan P, Nanda S, Paschke KD, Perdrisat CF, Punjabi V, Qattan IA, Ransome RD, Reimer PE, Reitz B, Saha A, Schulte EC, Sheyor R, Slifer K, Solvignon P, Sulkosky V, Urciuoli GM, Voutier E, Wang K, Wijesooriya K, Wojtsekhowski B, and Zhu L

Abstract

We measured the angular dependence of the three recoil-proton polarization components in two-body photodisintegration of the deuteron at a photon energy of 2 GeV. These new data provide a benchmark for calculations based on quantum chromodynamics. Two of the five existing models have made predictions of polarization observables. Both explain the longitudinal polarization transfer satisfactorily. Transverse polarizations are not well described, but suggest isovector dominance.

Published
2007
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19. Precision measurements of the nucleon strange form factors at Q2 approximately 0.1 GeV2.

Author

Acha A, Aniol KA, Armstrong DS, Arrington J, Averett T, Bailey SL, Barber J, Beck A, Benaoum H, Benesch J, Bertin PY, Bosted P, Butaru F, Burtin E, Cates GD, Chao YC, Chen JP, Chudakov E, Cisbani E, Craver B, Cusanno F, De Leo R, Decowski P, Deur A, Feuerbach RJ, Finn JM, Frullani S, Fuchs SA, Fuoti K, Gilman R, Glesener LE, Grimm K, Grames JM, Hansen JO, Hansknecht J, Higinbotham DW, Holmes R, Holmstrom T, Ibrahim H, de Jager CW, Jiang X, Katich J, Kaufman LJ, Kelleher A, King PM, Kolarkar A, Kowalski S, Kuchina E, Kumar KS, Lagamba L, LaViolette P, LeRose J, Lindgren RA, Lhuillier D, Liyanage N, Margaziotis DJ, Markowitz P, Meekins DG, Meziani ZE, Michaels R, Moffit B, Nanda S, Nelyubin V, Otis K, Paschke KD, Phillips SK, Poelker M, Pomatsalyuk R, Potokar M, Prok Y, Puckett A, Qian X, Qiang Y, Reitz B, Roche J, Saha A, Sawatzky B, Singh J, Slifer K, Sirca S, Snyder R, Solvignon P, Souder PA, Stutzman ML, Subedi R, Suleiman R, Sulkosky V, Tobias WA, Ulmer PE, Urciuoli GM, Wang K, Whitbeck A, Wilson R, Wojtsekhowski B, Yao H, Ye Y, Zhan X, Zheng X, Zhou S, and Ziskin V

Abstract

We report new measurements of the parity-violating asymmetry A(PV) in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with approximately 6.0 degrees . The 4He result is A(PV)=(+6.40+/-0.23(stat)+/-0.12(syst))x10(-6). The hydrogen result is A(PV)=(-1.58+/-0.12(stat)+/-0.04(syst))x10(-6). These results significantly improve constraints on the electric and magnetic strange form factors G(E)(s) and G(M)(s). We extract G(E)(s)=0.002+/-0.014+/-0.007 at =0.077 GeV2, and G(E)(s)+0.09G(M)(s)=0.007+/-0.011+/-0.006 at =0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions.

Published
2007
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20. Parity-violating electron scattering from 4He and the strange electric form factor of the nucleon.

Author

Aniol KA, Armstrong DS, Averett T, Benaoum H, Bertin PY, Burtin E, Cahoon J, Cates GD, Chang CC, Chao YC, Chen JP, Choi S, Chudakov E, Craver B, Cusanno F, Decowski P, Deepa D, Ferdi C, Feuerbach RJ, Finn JM, Frullani S, Fuoti K, Garibaldi F, Gilman R, Glamazdin A, Gorbenko V, Grames JM, Hansknecht J, Higinbotham DW, Holmes R, Holmstrom T, Humensky TB, Ibrahim H, de Jager CW, Jiang X, Kaufman LJ, Kelleher A, Kolarkar A, Kowalski S, Kumar KS, Lambert D, LaViolette P, LeRose J, Lhuillier D, Liyanage N, Margaziotis DJ, Mazouz M, McCormick K, Meekins DG, Meziani ZE, Michaels R, Moffit B, Monaghan P, Munoz-Camacho C, Nanda S, Nelyubin V, Neyret D, Paschke KD, Poelker M, Pomatsalyuk R, Qiang Y, Reitz B, Roche J, Saha A, Singh J, Snyder R, Souder PA, Subedi R, Suleiman R, Sulkosky V, Tobias WA, Urciuoli GM, Vacheret A, Voutier E, Wang K, Wilson R, Wojtsekhowski B, and Zheng X

Abstract

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 4He at an average scattering angle = 5.7 degrees and a four-momentum transfer Q2 = 0.091 GeV2 . From these data, for the first time, the strange electric form factor of the nucleon G(E)s can be isolated. The measured asymmetry of A(PV) = (6.72 +/- 0.84(stat) +/- 0.21(syst) x 10(-6) yields a value of G(E)s = -0.038 +/- 0.042(stat) +/- 0.010(syst), consistent with zero.

Published
2006
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21. Precision measurement of the weak mixing angle in Møller scattering.

Author

Anthony PL, Arnold RG, Arroyo C, Bega K, Biesiada J, Bosted PE, Bower G, Cahoon J, Carr R, Cates GD, Chen JP, Chudakov E, Cooke M, Decowski P, Deur A, Emam W, Erickson R, Fieguth T, Field C, Gao J, Gary M, Gustafsson K, Hicks RS, Holmes R, Hughes EW, Humensky TB, Jones GM, Kaufman LJ, Keller L, Kolomensky YG, Kumar KS, LaViolette P, Lhuillier D, Lombard-Nelsen RM, Marshall Z, Mastromarino P, McKeown RD, Michaels R, Niedziela J, Olson M, Paschke KD, Peterson GA, Pitthan R, Relyea D, Rock SE, Saxton O, Singh J, Souder PA, Szalata ZM, Turner J, Tweedie B, Vacheret A, Walz D, Weber T, Weisend J, Woods M, and Younus I

Abstract

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV) = [-131 +/- 14(stat) +/- 10(syst)] x 10(-9), leading to the determination of the weak mixing angle sin2(thetaW(eff) = 0.2397 +/- 0.0010(stat) +/- 0.0008(syst), evaluated at Q2 = 0.026 GeV2. Combining this result with the measurements of sin2(thetaW(eff) at the Z0 pole, the running of the weak mixing angle is observed with over 6sigma significance. The measurement sets constraints on new physics effects at the TeV scale.

Published
2005
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22. Observation of parity nonconservation in møller scattering.

Author

Anthony PL, Arnold RG, Arroyo C, Baird K, Bega K, Biesiada J, Bosted PE, Breuer M, Carr R, Cates GD, Chen JP, Chudakov E, Cooke M, Decker FJ, Decowski P, Deur A, Emam W, Erickson R, Fieguth T, Field C, Gao J, Gustafsson K, Hicks RS, Holmes R, Hughes EW, Humensky TB, Jones GM, Kaufman LJ, Kolomensky YG, Kumar KS, Lhuillier D, Lombard-Nelsen R, Mastromarino P, Mayer B, McKeown RD, Michaels R, Olson M, Paschke KD, Peterson GA, Pitthan R, Pope K, Relyea D, Rock SE, Saxton O, Shapiro G, Singh J, Souder PA, Szalata ZM, Tobias WA, Tonguc BT, Turner J, Tweedie B, Vacheret A, Walz D, Weber T, Weisend J, Whittum D, Woods M, and Younus I

Abstract

We report a measurement of the parity-violating asymmetry in fixed target electron-electron (Møller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)] x 10(-9). This first direct observation of parity nonconservation in Møller scattering leads to a measurement of the electron's weak charge at low energy Q(e)(W)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin((2)theta(W)(M(Z))((-)MS)=0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory).

Published
2004
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23. Measurement of spin-transfer observables in p p-->Lambda Lambda at 1.637 GeV/c.

Author

Bassalleck B, Berdoz A, Bradtke C, Bröders R, Bunker B, Dennert H, Dutz H, Eilerts S, Eyrich W, Fields D, Fischer H, Franklin G, Franz J, Gehring R, Geyer R, Goertz S, Harmsen J, Hauffe J, Heinsius FH, Hertzog D, Johansson T, Jones T, Khaustov P, Kilian K, Kingsberry P, Kriegler E, Lowe J, Meier A, Metzger A, Meyer CA, Meyer W, Moosburger M, Oelert W, Paschke KD, Plückthun M, Pomp S, Quinn B, Radtke E, Reicherz G, Röhrich K, Sachs K, Schmitt H, Schoch B, Sefzick T, Stinzing F, Stotzer R, Tayloe R, and Wirth S

Abstract

Spin-transfer observables for p p-->Lambda Lambda have been measured using a transversely polarized frozen-spin target and a beam momentum of 1.637 GeV/c. Current models of the reaction near threshold are in good agreement with existing measurements performed with unpolarized particles in the initial state but produce conflicting predictions for the spin-transfer observables Dnn and Knn (the normal-to-normal depolarization and polarization transfer), which are measurable only with polarized target or beam. Measurements of Dnn and Knn presented here are found to be in disagreement with predictions from these models.

Published
2002
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