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Your search keyword '"Abrahamyan, S."' showing total 5 results
Start Over Author "Abrahamyan, S." Publisher american physical society
5 results on '"Abrahamyan, S."'

1. Search for a New Gauge Boson in Electron-Nucleus Fixed-Target Scattering by the APEX Experiment

Author

Massachusetts Institute of Technology. Laboratory for Nuclear Science, Sulkosky, Vincent, Kelleher, Aidan Michael, Huang, J., Hansen, J.O., Iqbal, S., Abrahamyan, S., Ahmed, Z., Allada, Kalyan C., Anez, D., Averett, T., Barbieri, A., Bartlett, K., Beacham, J., Bono, J., Boyce, J. R., Brindza, P., Camsonne, A., Cranmer, K., Dalton, M. M., de Jager, C. W., Donaghy, J., Essig, R., Field, C., Folts, E., Gasparian, A., Goeckner-Wald, N., Gomez, J., Graham, M., Higinbotham, D. W., Holmstrom, T., Jaros, J., Jensen, E., Khandaker, M., LeRose, J. J., Lindgren, R., Liyanage, N., Long, E., Mammei, J., Markowitz, P., Maruyama, T., Maxwell, V., Mayilyan, S., McDonald, J., Michaels, R., Moffeit, K., Nelyubin, V., Odian, A., Oriunno, M., Partridge, R., Paolone, M., Piasetzky, E., Pomerantz, I., Qiang, Y., Riordan, S., Roblin, Y., Sawatzky, B., Schuster, P., Segal, J., Selvy, L., Shahinyan, A., Subedi, R., Stepanyan, S., Toro, N., Walz, D., Wojtsekhowski, B., Zhang, J., Massachusetts Institute of Technology. Laboratory for Nuclear Science, Sulkosky, Vincent, Kelleher, Aidan Michael, Huang, J., Hansen, J.O., Iqbal, S., Abrahamyan, S., Ahmed, Z., Allada, Kalyan C., Anez, D., Averett, T., Barbieri, A., Bartlett, K., Beacham, J., Bono, J., Boyce, J. R., Brindza, P., Camsonne, A., Cranmer, K., Dalton, M. M., de Jager, C. W., Donaghy, J., Essig, R., Field, C., Folts, E., Gasparian, A., Goeckner-Wald, N., Gomez, J., Graham, M., Higinbotham, D. W., Holmstrom, T., Jaros, J., Jensen, E., Khandaker, M., LeRose, J. J., Lindgren, R., Liyanage, N., Long, E., Mammei, J., Markowitz, P., Maruyama, T., Maxwell, V., Mayilyan, S., McDonald, J., Michaels, R., Moffeit, K., Nelyubin, V., Odian, A., Oriunno, M., Partridge, R., Paolone, M., Piasetzky, E., Pomerantz, I., Qiang, Y., Riordan, S., Roblin, Y., Sawatzky, B., Schuster, P., Segal, J., Selvy, L., Shahinyan, A., Subedi, R., Stepanyan, S., Toro, N., Walz, D., Wojtsekhowski, B., and Zhang, J.

Abstract

We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α′ to electrons. Such a particle A′ can be produced in electron-nucleus fixed-target scattering and then decay to an e[superscript +]e[superscript -] pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175–250 MeV, found no evidence for an A′→e[superscript +]e[superscript -] reaction, and set an upper limit of α′/α≃10[superscript -6]. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.

Published
2012

2. New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei.

Author

Abrahamyan, S., Acha, A., Afanasev, A., Ahmed, Z., Albataineh, H., Aniol, K., Armstrong, D.S., Armstrong, W., Arrington, J., Averett, T., Babineau, B., Bailey, S.L., Barber, J., Barbieri, A., Beck, A., Bellini, V., Beminiwattha, R., Benaoum, H., Benesch, J., and Benmokhtar, F.

Subjects
*ELASTIC scattering, *ELECTRON scattering, *HEAVY nuclei, *SCATTERING (Physics), *NUCLEAR structure
Abstract

We have measured the beam-normal single-spin asymmetry An in the elastic scattering of 1-3 GeV transversely polarized electrons from 1H and for the first time from 4He, 12C, and 208Pb. For 1H, 4He, and 12C, the measurements are in agreement with calculations that relate An to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the 208Pb result is significantly smaller than the corresponding prediction using the same formalism. These results suggest that a systematic set of new An measurements might emerge as a new and sensitive probe of the structure of heavy nuclei [ABSTRACT FROM AUTHOR]

Published
2012
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3. Search for a New Gauge Boson in Electron-Nucleus Fixed-Target Scattering by the APEX Experiment.

Author

Abrahamyan, S., Ahmed, Z., Allada, K., Anez, D., Averett, T., Barbieri, A., Bartlett, K., Beacham, J., Bono, J., Boyce, J. R., Brindza, P., Camsonne, A., Cranmer, K., Dalton, M. M., de Jager, C. W., Donaghy, J., Essig, R., Field, C., Folts, E., and Gasparian, A.

Subjects
*BOSONS, *ELECTRON-nucleus scattering, *QUANTUM electrodynamics, *PROTONS, *TANTALUM, *CALORIMETERS
Abstract

We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus fixed-target scattering and then decay to an e+ e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A' → e+e- reaction, and set an upper limit of α'/α ≃ 10-6. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces. [ABSTRACT FROM AUTHOR]

Published
2011
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4. 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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5. Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp.

Author

Riordan S, Abrahamyan S, Craver B, Kelleher A, Kolarkar A, Miller J, Cates GD, Liyanage N, Wojtsekhowski B, Acha A, Allada K, Anderson B, Aniol KA, Annand JR, Arrington J, Averett T, Beck A, Bellis M, Boeglin W, Breuer H, Calarco JR, Camsonne A, Chen JP, Chudakov E, Coman L, Crowe B, Cusanno F, Day D, Degtyarenko P, Dolph PA, Dutta C, Ferdi C, Fernández-Ramírez C, Feuerbach R, Fraile LM, Franklin G, Frullani S, Fuchs S, Garibaldi F, Gevorgyan N, Gilman R, Glamazdin A, Gomez J, Grimm K, Hansen JO, Herraiz JL, Higinbotham DW, Holmes R, Holmstrom T, Howell D, de Jager CW, Jiang X, Jones MK, Katich J, Kaufman LJ, Khandaker M, Kelly JJ, Kiselev D, Korsch W, LeRose J, Lindgren R, Markowitz P, Margaziotis DJ, Beck SM, Mayilyan S, McCormick K, Meziani ZE, Michaels R, Moffit B, Nanda S, Nelyubin V, Ngo T, Nikolenko DM, Norum B, Pentchev L, Perdrisat CF, Piasetzky E, Pomatsalyuk R, Protopopescu D, Puckett AJ, Punjabi VA, Qian X, Qiang Y, Quinn B, Rachek I, Ransome RD, Reimer PE, Reitz B, Roche J, Ron G, Rondon O, Rosner G, Saha A, Sargsian MM, Sawatzky B, Segal J, Shabestari M, Shahinyan A, Shestakov Y, Singh J, Sirca S, Souder P, Stepanyan S, Stibunov V, Sulkosky V, Tajima S, Tobias WA, Udias JM, Urciuoli GM, Vlahovic B, Voskanyan H, Wang K, Wesselmann FR, Vignote JR, Wood SA, Wright J, Yao H, and Zhu X

Abstract

The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.

Published
2010
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