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1. Qweak: First Direct Measurement of the Proton’s Weak Charge

Author

Androic D., Armstrong D.S., Asaturyan A., Averett T., Balewski J., Bartlett K., Beaufait J., Beminiwattha R.S., Benesch J., Benmokhtar F., Birchall J., Carlini R.D., Cates G.D., Cornejo J.C., Covrig S., Dalton M.M., Davis C.A., Deconinck W., Diefenbach J., Dowd J.F., Dunne J.A., Dutta D., Duvall W.S., Elaasar M., Falk W.R., Finn J.M., Forest T., Gal C., Gaskell D., Gericke M.T.W., Grames J., Gray V.M., Grimm K., Guo F., Hoskins J.R., Johnston K., Jones D., Jones M., Jones R., Kargiantoulakis M., King P.M., Korkmaz E., Kowalski S., Leacock J., Leckey J., Lee A.R., Lee J.H., Lee L., MacEwan S., Mack D., Magee J.A., Mahurin R., Mammei J., Martin J.W., McHugh M.J., Meekins D., Mei J., Michaels R., Micherdzinska A., Mkrtchyan A., Mkrtchyan H., Morgan N., Myers K.E., Narayan A., Ndukum L.Z., Nelyubin V., Nuhait H., Nuruzzaman, van Oers W.T.H, Opper A.K., Page S.A., Pan J., Paschke K.D., Phillips S.K., Pitt M.L., Poelker M., Rajotte J.F., Ramsay W.D., Roche J., Sawatzky B., Seva T., Shabestari M.H., Silwal R., Simicevic N., Smith G.R., Solvignon P., Spayde D.T., Subedi A., Subedi R., Suleiman R., Tadevosyan V., Tobias W.A., Tvaskis V., Waidyawansa B., Wang P., Wells S.P., Wood S.A., Yang S., Young R.D., Zang P., and Zhamkochyan S.

Subjects
Physics, QC1-999
Abstract

The Qweak experiment, which took data at Jefferson Lab in the period 2010 - 2012, will precisely determine the weak charge of the proton by measuring the parity-violating asymmetry in elastic e-p scattering at 1.1 GeV using a longitudinally polarized electron beam and a liquid hydrogen target at a low momentum transfer of Q2 = 0.025 (GeV/c)2. The weak charge of the proton is predicted by the Standard Model and any significant deviation would indicate physics beyond the Standard Model. The technical challenges and experimental apparatus for measuring the weak charge of the proton will be discussed, as well as the method of extracting the weak charge of the proton. The results from a small subset of the data, that has been published, will also be presented. Furthermore an update will be given of the current status of the data analysis.

Published
2017
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2. Deeply virtual Compton scattering cross section at high Bjorken $x_B$

Author

Georges, F., Rashad, M. N. H., Stefanko, A., Dlamini, M., Karki, B., Ali, S. F., Lin, P-J., Ko, H-S, Israel, N., Adikaram, D., Ahmed, Z., Albataineh, H., Aljawrneh, B., Allada, K., Allison, S., Alsalmi, S., Androic, D., Aniol, K., Annand, J., Atac, H., Averett, T., Gayoso, C. Ayerbe, Bai, X., Bane, J., Barcus, S., Bartlett, K., Bellini, V., Beminiwattha, R., Bericic, J., Biswas, D., Brash, E., Bulumulla, D., Campbell, J., Camsonne, A., Carmignotto, M., Castellano, J., Chen, C., Chen, J-P., Chetry, T., Christy, M. E., Cisbani, E., Clary, B., Cohen, E., Compton, N., Cornejo, J. C., Dusa, S. Covrig, Crowe, B., Danagoulian, S., Danley, T., De Persio, F., Deconinck, W., Defurne, M., Desnault, C., Di, D., Duer, M., Duran, B., Ent, R., Fanelli, C., Franklin, G., Fuchey, E., Gal, C., Gaskell, D., Gautam, T., Glamazdin, O., Gnanvo, K., Gray, V. M., Gu, C., Hague, T., Hamad, G., Hamilton, D., Hamilton, K., Hansen, O., Hauenstein, F., Henry, W., Higinbotham, D. W., Holmstrom, T., Horn, T., Huang, Y., Huber, G. M., Hyde, C., Ibrahim, H., Jen, C-M., Jin, K., Jones, M., Kabir, A., Keppel, C., Khachatryan, V., King, P. M., Li, S., Li, W. B., Liu, J., Liu, H., Liyanage, A., Magee, J., Malace, S., Mammei, J., Markowitz, P., McClellan, E., Mazouz, M., Meddi, F., Meekins, D., Mesik, K., Michaels, R., Mkrtchyan, A., Montgomery, R., Camacho, C. Muñoz, Myers, L. S., Nadel-Turonski, P., Nazeer, S. J., Nelyubin, V., Nguyen, D., Nuruzzaman, N., Nycz, M., Obretch, O. F., Ou, L., Palatchi, C., Pandey, B., Park, S., Park, K., Peng, C., Pomatsalyuk, R., Pooser, E., Puckett, A. J. R., Punjabi, V., Quinn, B., Rahman, S., Reimer, P. E., Roche, J., Sapkota, I., Sarty, A., Sawatzky, B., Saylor, N. H., Schmookler, B., Shabestari, M. H., Shahinyan, A., Sirca, S., Smith, G. R., Sooriyaarachchilage, S., Sparveris, N., Spies, R., Su, T., Subedi, A., Sulkosky, V., Sun, A., Thorne, L., Tian, Y., Ton, N., Tortorici, F., Trotta, R., Urciuoli, G. M., Voutier, E., Waidyawansa, B., Wang, Y., Wojtsekhowski, B., Wood, S., Yan, X., Ye, L., Ye, Z., Yero, C., Zhang, J., Zhao, Y., and Zhu, P.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report high-precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section at high values of the Bjorken variable $x_B$. DVCS is sensitive to the Generalized Parton Distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton Form Factors (CFFs) of the nucleon as a function of $x_B$, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

Published
2022
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3. First Determination of the 27Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement

Author

QWeak Collaboration, Androic, D., Armstrong, D. S., Bartlett, K., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Dusa, S. Covrig, Dalton, M. M., Davis, C. A., Deconinck, W., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gal, C., Gaskell, D., Gericke, M. T. W., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Jones, D. C., Jones, M. K., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Mesick, K. E., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H, Owen, V. F., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Radloff, R. W., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Zang, P., Zhamkochyan, S., Christy, M. E., Horowitz, C. J., Fattoyev, F. J., and Lin, Z.

Subjects
Nuclear Experiment
Abstract

We report the first measurement of the parity-violating elastic electron scattering asymmetry on 27Al. The 27Al elastic asymmetry is A_PV = 2.16 +- 0.11 (stat) +- 0.16 (syst) ppm, and was measured at =0.02357 +- 0.0001 GeV^2, = 7.61 +- 0.02 degrees, and = 1.157 GeV with the Qweak 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 27Al neutron radius R_n = 2.89 +- 0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_n-R_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 27Al weak radius R_w = 3.00 +- 0.15 fm, and the weak skin thickness R_wk - R_ch = -0.04 +- 0.15 fm. The weak form factor at this Q^2 is F_wk = 0.39 +- 0.04., Comment: Revised version after referee's comments and suggestions. Some improvements and clarification to the text, no changes to the figures, tables, results or conclusions. 7 pages, 3 figures, 3 tables

Published
2021
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4. Measurement of the Beam-Normal Single-Spin Asymmetry for Elastic Electron Scattering from $^{12}$C and $^{27}$Al

Author

QWeak Collaboration, Androic, D., Armstrong, D. S., Asaturyan, A., Bartlett, K., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Christy, M. E., Cornejo, J. C., Dusa, S. Covrig, Dalton, M. M., Davis, C. A., Deconinck, W., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elassar, M., Falk, W. R., Finn, J. M., Forest, T., Gal, C., Gaskell, D., Gericke, M. T. W., Gray, V. M., Guo, F., Hoskins, J. R., Jones, D. C., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J. P., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mesick, K. E., Michaels, R., Mkrtchyan, A., Mkrtchyan, H., Narayan, A., Ndukum, L. Z., Nuruzzaman, Nelyubin, V., van Oers, W. T. H, Owen, V. F., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Radloff, R. W., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Tadevosyan, V., Tobias, W. A., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Zang, P., and Zhamkochyan, S.

Subjects
Nuclear Experiment
Abstract

We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries $B_n$ on $^{12}$C and $^{27}$Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements 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 energy of 1.158 GeV. The average lab scattering angle for both targets was 7.7 degrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561 GeV). The asymmetries are $B_n$ = -10.68 $\pm$ 0.90 stat) $\pm$ 0.57 (syst) ppm for $^{12}$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 are compared to existing data. When scaled by Z/A, the Q-dependence of all the far-forward angle (theta < 10 degrees) data from $^{1}$H to $^{27}$Al can be described by the same slope out to $Q \approx 0.35$ GeV. Larger-angle data from other experiments in the same Q range are consistent with a slope about twice as steep., Comment: Minor changes after refereeing; version as accepted for Physical Review C. Cosmetic changes to several figures, one author added. 22 pages, 8 figures

Published
2021
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5. Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering

Author

Christy, M. E., Gautam, T., Ou, L., Schmookler, B., Wang, Y., Adikaram, D., Ahmed, Z., Albataineh, H., Ali, S. F., Aljawrneh, B., Allada, K., Allison, S. L., Alsalmi, S., Androic, D., Aniol, K., Annand, J., Arrington, J., Atac, H., Averett, T., Gayoso, C. Ayerbe, Bai, X., Bane, J., Barcus, S., Bartlett, K., Bellini, V., Beminiwattha, R., Bericic, J., Bhatt, H., Bhetuwal, D., Biswas, D., Brash, E., Bulumulla, D., Camacho, C. M., Campbell, J., Camsonne, A., Carmignotto, M., Castellanos, J., Chen, C., Chen, J-P., Chetry, T., Cisbani, E., Clary, B., Cohen, E., Compton, N., Cornejo, J. C., Dusa, S. Covrig, Crowe, B., Danagoulian, S., Danley, T., Deconinck, W., Defurne, M., Desnault, C., Di, D., Dlamini, M., Duer, M., Duran, B., Ent, R., Fanelli, C., Fuchey, E., Gal, C., Gaskell, D., Georges, F., Gilad, S., Glamazdin, O., Gnanvo, K., Gramolin, A. V., Gray, V. M., Gu, C., Habarakada, A., Hague, T., Hamad, G., Hamilton, D., Hamilton, K., Hansen, O., Hauenstein, F., Hernandez, A. V., Henry, W., Higinbotham, D. W., Holmstrom, T., Horn, T., Huang, Y., Huber, G. M., Hyde, C., Ibrahim, H., Israel, N., Jen, C-M., Jin, K., Jones, M., Kabir, A., Karki, B., Keppel, C., Khachatryan, V., King, P. M., Li, S., Li, W., Liu, H., Liu, J., Liyanage, A. H., Mack, D., Magee, J., Malace, S., Mammei, J., Markowitz, P., Mayilyan, S., McClellan, E., Meddi, F., Meekins, D., Mesick, K., Michaels, R., Mkrtchyan, A., Moffit, B., Montgomery, R., Myers, L. S., Nadel-Turonski, P., Nazeer, S. J., Nelyubin, V., Nguyen, D., Nuruzzaman, N., Nycz, M., Obrecht, R. F., Ohanyan, K., Palatchi, C., Pandey, B., Park, K., Park, S., Peng, C., Persio, F. D., Pomatsalyuk, R., Pooser, E., Puckett, A. J. R., Punjabi, V., Quinn, B., Rahman, S., Rashad, M. N. H., Riordan, S., Roche, J., Sapkota, I., Sarty, A., Sawatzky, B., Saylor, N. H., Shabestari, M. H., Shahinyan, A., Sirca, S., Smith, G. R., Sooriyaarachchilage, S., Sparveris, N., Spies, R., Stefanko, A., Su, T., Subedi, A., Sulkosky, V., Sun, A., Tan, Y., Thorne, L., Ton, N., Tortorici, F., Trotta, R., Uniyal, R., Urciuoli, G. M., Voutier, E., Waidyawansa, B., Wojtsekhowski, B., Wood, S., Yan, X., Ye, L., Ye, Z. H., Yero, C., Zhang, J., Zhao, Y. X., and Zhu, P.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q$^2$) up to 15.75~\gevsq. Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q$^2$ and double the range over which a longitudinal/transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q$^2$ and attributed to hard two-photon exchange (TPE) effects, extending to 8~(GeV/c)$^2$ the range of Q$^2$ for which a discrepancy is established at $>$95\% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q$^2$., Comment: 7 pages, 2 figures

Published
2021
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6. Early Results from the Qweak Experiment

Author

Androic D., Armstrong D.S., Asaturyan A., Averett T., Balewski J., Beaufait J., Beminiwattha R.S., Benesch J., Benmokhtar F., Birchall J., Carlini R.D., Cates G.D., Cornejo J.C., Covrig S., Dalton M.M., Davis C.A., Deconinck W., Diefenbach J., Dowd J.F., Dunne J.A., Dutta D., Duvall W.S., Elaasar M., Falk W.R., Finn J.M., Forest T., Gaskell D., Gericke M.T.W., Grames J., Gray V.M., Grimm K., Guo F., Hoskins J.R., Johnston K., Jones D., Jones M., Jones R., Kargiantoulakis M., King P.M., Korkmaz E., Kowalski S., Leacock J., Leckey J., Lee A.R., Lee J.H., Lee L., MacEwan S., Mack D., Magee J.A., Mahurin R., Mammei J., Martin J., McHugh M.J., Meekins D., Mei J., Michaels R., Micherdzinska A., Mkrtchyan A., Mkrtchyan H., Morgan N., Myers K.E., Narayan A., Ndukum L.Z., Nelyubin V., Nuruzzaman, van Oers W.T.H, Opper A.K., Page S.A., Pan J., Paschke K., Phillips S.K., Pitt M.L., Poelker M., Rajotte J.F., Ramsay W.D., Roche J., Sawatzky B., Seva T., Shabestari M.H., Silwal R., Simicevic N., Smith G.R., Solvignon P., Spayde D.T., Subedi A., Subedi R., Suleiman R., Tadevosyan V., Tobias W.A., Tvaskis V., Waidyawansa B., Wang P., Wells S.P., Wood S.A., Yang S., Young R.D., and Zhamkochyan S.

Subjects
Physics, QC1-999
Abstract

A subset of results from the recently completed Jefferson Lab Qweak experiment are reported. This experiment, sensitive to physics beyond the Standard Model, exploits the small parity-violating asymmetry in elastic e→p$\vec e{\rm{p}}$ scattering to provide the first determination of the proton’s weak charge Qwp$Q_w^p$. The experiment employed a 180 μA longitudinally polarized 1.16 GeV electron beam on a 35 cm long liquid hydrogen target. Scattered electrons in the angular range 6° < θ < 12° corresponding to Q2 = 0.025 GeV2 were detected in eight Cerenkov detectors arrayed symmetrically around the beam axis. The goals of the experiment were to provide a measure of e→p$\vec e{\rm{p}}$ to 4.2% (combined statisstatistical and systematic error), which implies a measure of sin2(θw) at the level of 0.3%, and to help constrain the vector weak quark charges C1u and C1d. The experimental method is described, with particular focus on the challenges associated with the world’s highest power LH2 target. The new constraints on C1u and C1d provided by the subset of the experiment’s data analyzed to date will also be shown, together with the extracted weak charge of the neutron.

Published
2014
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7. Deep exclusive electroproduction of $\pi^0$ at high $Q^2$ in the quark valence regime

Author

The Jefferson Lab Hall A Collaboration, Dlamini, M., Karki, B., Ali, S. F., Lin, P-J., Georges, F., Ko, H-S, Israel, N., Rashad, M. N. H., Stefanko, A., Adikaram, D., Ahmed, Z., Albataineh, H., Aljawrneh, B., Allada, K., Allison, S., Alsalmi, S., Androic, D., Aniol, K., Annand, J., Atac, H., Averett, T., Gayoso, C. Ayerbe, Bai, X., Bane, J., Barcus, S., Bartlett, K., Bellini, V., Beminiwattha, R., Bericic, J., Biswas, D., Brash, E., Bulumulla, D., Campbell, J., Camsonne, A., Carmignotto, M., Castellano, J., Chen, C., Chen, J-P., Chetry, T., Christy, M. E., Cisbani, E., Clary, B., Cohen, E., Compton, N., Cornejo, J. C., Dusa, S. Covrig, Crowe, B., Danagoulian, S., Danley, T., De Persio, F., Deconinck, W., Defurne, M., Desnault, C., Di, D., Duer, M., Duran, B., Ent, R., Fanelli, C., Franklin, G., Fuchey, E., Gal, C., Gaskell, D., Gautam, T., Glamazdin, O., Gnanvo, K., Gray, V. M., Gu, C., Hague, T., Hamad, G., Hamilton, D., Hamilton, K., Hansen, O., Hauenstein, F., Henry, W., Higinbotham, D. W., Holmstrom, T., Horn, T., Huang, Y., Huber, G. M., Hyde, C., Ibrahim, H., Jen, C-M., Jin, K., Jones, M., Kabir, A., Keppel, C., Khachatryan, V., King, P. M., Li, S., Li, W., Liu, J., Liu, H., Liyanage, A., Magee, J., Malace, S., Mammei, J., Markowitz, P., McClellan, E., Meddi, F., Meekins, D., Mesik, K., Michaels, R., Mkrtchyan, A., Montgomery, R., Camacho, C. Munoz, Myers, L. S., Nadel-Turonski, P., Nazeer, S. J., Nelyubin, V., Nguyen, D., Nuruzzaman, N., Nycz, M., Obretch, O. F., Ou, L., Palatchi, C., Pandey, B., Park, S., Park, K., Peng, C., Pomatsalyuk, R., Pooser, E., Puckett, A. J. R., Punjabi, V., Quinn, B., Rahman, S., Reimer, P. E., Roche, J., Sapkota, I., Sarty, A., Sawatzky, B., Saylor, N. H., Schmookler, B., Shabestari, M. H., Shahinyan, A., Sirca, S., Smith, G. R., Sooriyaarachchilage, S., Sparveris, N., Spies, R., Su, T., Subedi, A., Sulkosky, V., Sun, A., Thorne, L., Tian, Y., Ton, N., Tortorici, F., Trotta, R., Urciuoli, G. M., Voutier, E., Waidyawansa, B., Wang, Y., Wojtsekhowski, B., Wood, S., Yan, X., Ye, L., Ye, Z., Yero, C., Zhang, J., Zhao, Y., and Zhu, P.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of $x_B$ (0.36, 0.48 and 0.60) and $Q^2$ (3.1 to 8.4 GeV$^2$) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions $d\sigma_L/dt+\epsilon d\sigma_T/dt$, $d\sigma_{TT}/dt$, $d\sigma_{LT}/dt$ and $d\sigma_{LT'}/dt$ are extracted as a function of the proton momentum transfer $t-t_{min}$. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross-section throughout this kinematic range. The data are well described by calculations based on transversity Generalized Parton Distributions coupled to a helicity flip Distribution Amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Published
2020
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8. Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering

Author

QWeak collaboration, Androic, D., Armstrong, D. S., Asaturyan, A., Bartlett, K., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Dusa, S. Covrig, Dalton, M. M., Davis, C. A., Deconinck, W., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gal, C., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Jones, D., Jones, M. K., Jones, R. T., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J. P., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Mesick, K. E., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H, Owen, V. F., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Radloff, R. W., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Zang, P., and Zhamkochyan, S.

Subjects
Nuclear Experiment
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 theta_lab = 7.9 degrees and a mean energy of 1.149 GeV. The asymmetry result is B_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 (theta_lab -> 0) where they should be most reliable., Comment: 6 pages, 3 figures; Slightly revised version, after referee's comments; accepted in PRL

Published
2020
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9. 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

10. Parity-Violating Inelastic Electron-Proton Scattering at Low $Q^2$ Above the Resonance Region

Author

QWeak Collaboration, Androic, D., Armstrong, D. S., Asaturyan, A., Bartlett, K., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Dalton, M. M., Davis, C. A., Deconinck, W., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Falk, W. R., Finn, J. M., Gal, C., Gaskell, D., Gericke, M. T. W., Grames, J., Guo, F., Hoskins, J. R., Jones, D., Jones, M. K., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mesick, K. E., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Narayan, A., Nelyubin, V., van Oers, W. T. H, Owen, V. F., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Radloff, R. W., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Tadevosyan, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., and Zang, P.

Subjects
Nuclear Experiment, High Energy Physics - Phenomenology
Abstract

We report the measurement of the parity-violating asymmetry for the inelastic scattering of electrons from the proton, at $Q^2 = 0.082$ GeV$^2$ and $ W = 2.23$ GeV, above the resonance region. The result $A_{\rm Inel} = - 13.5 \pm 2.0 ({\rm stat}) \pm 3.9 ({\rm syst})$~ppm agrees with theoretical calculations, and helps to validate the modeling of the $\gamma Z$ interference structure functions $F_1^{\gamma Z}$ and $F_2^{\gamma Z}$ used in those calculations, which are also used for determination of the two-boson exchange box diagram ($\Box_{\gamma Z}$) contribution to parity-violating elastic scattering measurements. A positive parity-violating asymmetry for inclusive $\pi^-$ production was observed, as well as positive beam-normal single-spin asymmetry for scattered electrons and a negative beam-normal single-spin asymmetry for inclusive $\pi^-$ production., Comment: 18 pages, 9 figures, version accepted in Physical Review C

Published
2019
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11. Precision Measurement of the Weak Charge of the Proton

Author

Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Bartlett, K., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Dusa, S. Covrig, Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gal, C., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Mesick, K. E., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuhait, H., Nuruzzaman, van Oers, W. T. H., Opper, A. K., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., Zang, P., and Zhamkochyan, S.

Subjects
Nuclear Experiment
Abstract

The fields of particle and nuclear physics have undertaken extensive programs to search for evidence of physics beyond that explained by current theories. The observation of the Higgs boson at the Large Hadron Collider completed the set of particles predicted by the Standard Model (SM), currently the best description of fundamental particles and forces. However, the theory's limitations include a failure to predict fundamental parameters and the inability to account for dark matter/energy, gravity, and the matter-antimater asymmetry in the universe, among other phenomena. Given the lack of additional particles found so far through direct searches in the post-Higgs era, indirect searches utilizing precise measurements of well predicted SM observables allow highly targeted alternative tests for physics beyond the SM. Indirect searches have the potential to reach mass/energy scales beyond those directly accessible by today's high-energy accelerators. The value of the weak charge of the proton Q_W^p is an example of such an indirect search, as it sets the strength of the proton's interaction with particles via the well-predicted neutral electroweak force. Parity violation (invariance under spatial inversion (x,y,z) -> (-x,-y,-z)) is violated only in the weak interaction, thus providing a unique tool to isolate the weak interaction in order to measure the proton's weak charge. Here we report Q_W^p=0.0719+-0.0045, as extracted from our measured parity-violating (PV) polarized electron-proton scattering asymmetry, A_ep=-226.5+-9.3 ppb. Our value of Q_W^p is in excellent agreement with the SM, and sets multi-TeV-scale constraints on any semi-leptonic PV physics not described within the SM., Comment: Direct link to Nature Version "https://rdcu.be/954U"

Published
2019
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12. A novel comparison of M{\o}ller and Compton electron-beam polarimeters

Author

Magee, J. A., Narayan, A., Jones, D., Beminiwattha, R., Cornejo, J. C., Dalton, M. M., Deconinck, W., Dutta, D., Gaskell, D., Martin, J. W., Paschke, K. D., Tvaskis, V., Asaturyan, A., Benesch, J., Cates, G., Cavness, B. S., Dillon-Townes, L. A., Hays, G., Hoskins, J., Ihloff, E., Jones, R., King, P. M., Kowalski, S., Kurchaninov, L., Lee, L., McCreary, A., McDonald, M., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Nelyubin, V., Page, S., Ramsay, W. D., Solvignon, P., Storey, D., Tobias, W. A., Urban, E., Vidal, C., Waidyawansa, B., Wang, P., and Zhamkotchyan, S.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

We have performed a novel comparison between electron-beam polarimeters based on M{\o}ller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents ($<$ 5 $\mu$A) during the $Q_{\rm weak}$ experiment in Hall C at Jefferson Lab. These low current measurements were bracketed by the regular high current (180 $\mu$A) operation of the Compton polarimeter. All measurements were found to be consistent within experimental uncertainties of 1% or less, demonstrating that electron polarization does not depend significantly on the beam current. This result lends confidence to the common practice of applying M{\o}ller measurements made at low beam currents to physics experiments performed at higher beam currents. The agreement between two polarimetry techniques based on independent physical processes sets an important benchmark for future precision asymmetry measurements that require sub-1% precision in polarimetry.

Published
2016
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13. Measurement of Parity-Violating Asymmetry in Electron-Deuteron Inelastic Scattering

Author

Wang, D., Pan, K., Subedi, R., Ahmed, Z., Allada, K., Aniol, K. A., Armstrong, D. S., Arrington, J., Bellini, V., Beminiwattha, R., Benesch, J., Benmokhtar, F., Bertozzi, W., Camsonne, A., Canan, M., Cates, G. D., Chen, J. -P., Chudakov, E., Cisbani, E., Dalton, M. M., de Jager, C. W., De Leo, R., Deconinck, W., Deng, X., Deur, A., Dutta, C., Fassi, L. El, Erler, J., Flay, D., Franklin, G. B., Friend, M., Frullani, S., Garibaldi, F., Gilad, S., Giusa, A., Glamazdin, A., Golge, S., Grimm, K., Hafidi, K., Hansen, J. -O., Higinbotham, D. W., Holmes, R., Holmstrom, T., Holt, R. J., Huang, J., Hyde, C. E., Jen, C. M., Jones, D., Kang, Hoyoung, King, P. M., Kowalski, S., Kumar, K. S., Lee, J. H., LeRose, J. J., Liyanage, N., Long, E., McNulty, D., Margaziotis, D. J., Meddi, F., Meekins, D. G., Mercado, L., Meziani, Z. -E., Michaels, R., Mihovilovic, M., Muangma, N., Mesick, K. E., Nanda, S., Narayan, A., Nelyubin, V., Nuruzzaman, A., Oh, Y., Parno, D., Paschke, K. D., Phillips, S. K., Qian, X., Qiang, Y., Quinn, B., Rakhman, A., Reimer, P. E., Rider, K., Riordan, S., Roche, J., Rubin, J., Russo, G., Saenboonruang, K., Saha, A., Sawatzky, B., Shahinyan, A., Silwal, R., Širca, S., Souder, P. A., Suleiman, R., Sulkosky, V., Sutera, C. M., Tobias, W. A., Urciuoli, G. M., Waidyawansa, B., Wojtsekhowski, B., Ye, L., Zhao, B., and Zheng, X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail., Comment: 50 pages, submitted to Phys. Rev. C

Published
2014
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14. The Q_weak Experimental Apparatus

Author

Qweak Collaboration, Allison, T., Anderson, M., Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T. D., Averill, R., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Bessuille, J., Birchall, J., Bonnell, E., Bowman, J., Brindza, P., Brown, D. B., Carlini, R. D., Cates, G. D., Cavness, B., Clark, G., Cornejo, J. C., Dusa, S. Covrig, Dalton, M. M., Davis, C. A., Dean, D. C., Deconinck, W., Diefenbach, J., Dow, K., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Echols, J. R., Elaasar, M., Falk, W. R., Finelli, K. D., Finn, J. M., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hansknecht, J., Harrison, D. J., Henderson, E., Hoskins, J. R., Ihloff, E., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., Kelsey, J., Khan, N., King, P. M., Korkmaz, E., Kowalski, S., Kubera, A., Leacock, J., Leckey, J. P., Lee, A. R., Lee, J. H., Lee, L., Liang, Y., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McCreary, A., McDonald, M. H., McHugh, M. J., Medeiros, P., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Musson, J., Mesick, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H., Opper, A. K., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roberts, W. R., Roche, J., Rose, P. W., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Sobczynski, S., Solvignon, P., Spayde, D. T., Stokes, B., Storey, D. W., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Urban, E., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Zhamkochyan, S., and Zielinski, R. B.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment, Physics - Accelerator Physics
Abstract

The Jefferson Lab Q_weak experiment determined the weak charge of the proton by measuring the parity-violating elastic scattering asymmetry of longitudinally polarized electrons from an unpolarized liquid hydrogen target at small momentum transfer. A custom apparatus was designed for this experiment to meet the technical challenges presented by the smallest and most precise ${\vec{e}}$p asymmetry ever measured. Technical milestones were achieved at Jefferson Lab in target power, beam current, beam helicity reversal rate, polarimetry, detected rates, and control of helicity-correlated beam properties. The experiment employed 180 microA of 89% longitudinally polarized electrons whose helicity was reversed 960 times per second. The electrons were accelerated to 1.16 GeV and directed to a beamline with extensive instrumentation to measure helicity-correlated beam properties that can induce false asymmetries. Moller and Compton polarimetry were used to measure the electron beam polarization to better than 1%. The electron beam was incident on a 34.4 cm liquid hydrogen target. After passing through a triple collimator system, scattered electrons between 5.8 degrees and 11.6 degrees were bent in the toroidal magnetic field of a resistive copper-coil magnet. The electrons inside this acceptance were focused onto eight fused silica Cerenkov detectors arrayed symmetrically around the beam axis. A total scattered electron rate of about 7 GHz was incident on the detector array. The detectors were read out in integrating mode by custom-built low-noise pre-amplifiers and 18-bit sampling ADC modules. The momentum transfer Q^2 = 0.025 GeV^2 was determined using dedicated low-current (~100 pA) measurements with a set of drift chambers before (and a set of drift chambers and trigger scintillation counters after) the toroidal magnet., Comment: 48 pages, 36 figures. Accepted by Nuclear Instruments and Methods A

Published
2014

15. Early Results from the Qweak Experiment

Author

Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cates, G. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gaskel, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J., McHugh, M. J., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Myers, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H, Opper, A. K., Page, S. A., Pan, J., Paschke, K., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., and Zhamkochyan, S.

Subjects
Nuclear Experiment
Abstract

A subset of results from the recently completed Jefferson Lab Qweak experiment are reported. This experiment, sensitive to physics beyond the Standard Model, exploits the small parity-violating asymmetry in elastic ep scattering to provide the first determination of the protons weak charge Qweak(p). The experiment employed a 180 uA longitudinally polarized 1.16 GeV electron beam on a 35 cm long liquid hydrogen target. Scattered electrons corresponding to Q2 of 0.025 GeV2 were detected in eight Cerenkov detectors arrayed symmetrically around the beam axis. The goals of the experiment were to provide a measure of Qweak(p) to 4.2 percent (combined statistical and systematic error), which implies a measure of sin2(thetaw) at the level of 0.3 percent, and to help constrain the vector weak quark charges C1u and C1d. The experimental method is described, with particular focus on the challenges associated with the worlds highest power LH2 target. The new constraints on C1u and C1d provided by the subset of the experiments data analyzed to date will also be shown, together with the extracted weak charge of the neutron., Comment: 8 pages, 4 figures, INPC2013

Published
2013
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16. First Determination of the Weak Charge of the Proton

Author

Qweak Collaboration, Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cates, G. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Myers, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H, Opper, A. K., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., and Zhamkochyan, S.

Subjects
Nuclear Experiment
Abstract

The Qweak experiment has measured the parity-violating asymmetry in polarized e-p elastic scattering at Q^2 = 0.025(GeV/c)^2, employing 145 microamps of 89% longitudinally polarized electrons on a 34.4cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run are reported here, constituting approximately 4% of the data collected in the experiment. From these initial results the measured asymmetry is Aep = -279 +- 35 (statistics) +- 31 (systematics) ppb, which is the smallest and most precise asymmetry ever measured in polarized e-p scattering. The small Q^2 of this experiment has made possible the first determination of the weak charge of the proton, QpW, by incorporating earlier parity-violating electron scattering (PVES) data at higher Q^2 to constrain hadronic corrections. The value of QpW obtained in this way is QpW(PVES) = 0.064 +- 0.012, in good agreement with the Standard Model prediction of QpW(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 QnW(PVES+APV) = -0.975 +- 0.010., Comment: 7 pages, 3 figures

Published
2013
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17. Measurement of the Parity-Violating Asymmetry in Electron-Deuteron Scattering in the Nucleon Resonance Region

Author

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

Subjects
Nuclear Experiment
Abstract

We report on parity-violating asymmetries in the nucleon resonance region measured using $5 - 6$ GeV longitudinally polarized electrons scattering off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the $\Delta(1232)$, and provide a verification of quark-hadron duality in the nucleon electroweak $\gamma Z$ interference structure functions at the (10-15)% level. The results are of particular interest to models relevant for calculating the $\gamma Z$ box-diagram corrections to elastic parity-violating electron scattering measurements., Comment: 7 pages, 1 figure, to appear in Phys. Rev. Lett

Published
2013
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18. New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei

Author

HAPPEX, The, Collaborations, PREX, 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., Benmokhtar, F., Bertin, P., Bielarski, T., Boeglin, W., Bosted, P., Butaru, F., Burtin, E., Cahoon, J., Camsonne, A., Canan, M., Carter, P., Chang, C. C., Cates, G. D., Chao, Y. C., Chen, C., Chen, J. P., Choi, Seonho, Chudakov, E., Cisbani, E., Craver, B., Cusanno, F., Dalton, M. M., De Leo, R., de Jager, K., Deconinck, W., Decowski, P., Deepa, D., Deng, X., Deur, A., Dutta, D., Etile, A., Ferdi, C., Feuerbach, R. J., Finn, J. M., Flay, D., Franklin, G. B., Friend, M., Frullani, S., Fuchey, E., Fuchs, S. A., Fuoti, K., Garibaldi, F., Gasser, E., Gilman, R., Giusa, A., Glamazdin, A., Glesener, L. E., Gomez, J., Gorchtein, M., Grames, J., Grimm, K., Gu, C., Hansen, O., Hansknecht, J., Hen, O., Higinbotham, D. W., Holmes, R. S., Holmstrom, T., Horowitz, C. J., Hoskins, J., Huang, J., Humensky, T. B., Hyde, C. E., Ibrahim, H., Itard, F., Jen, C. M., Jensen, E., Jiang, X., Jin, G., Johnston, S., Katich, J., Kaufman, L. J., Kelleher, A., Kliakhandler, K., King, P. M., Kolarkar, A., Kowalski, S., Kuchina, E., Kumar, K. S., Lagamba, L., Lambert, D., LaViolette, P., Leacock, J., Leckey IV, J., Lee, J. H., LeRose, J. J., Lhuillier, D., Lindgren, R., Liyanage, N., Lubinsky, N., Mammei, J., Mammoliti, F., Margaziotis, D. J., Markowitz, P., Mazouz, M., McCormick, K., McCreary, A., McNulty, D., Meekins, D. G., Mercado, L., Meziani, Z. E., Michaels, R. W., Mihovilovic, M., Moffit, B., Monaghan, P., Muangma, N., Munoz-Camacho, C., Nanda, S., Nelyubin, V., Neyret, D., Nuruzzaman, Oh, Y., Otis, K., Palmer, A., Parno, D., Paschke, K. D., Phillips, S. K., Poelker, M., Pomatsalyuk, R., Posik, M., Potokar, M., Prok, K., Puckett, A. J. R., Qian, X., Qiang, Y., Quinn, B., Rakhman, A., Reimer, P. E., Reitz, B., Riordan, S., Roche, J., Rogan, P., Ron, G., Russo, G., Saenboonruang, K., Saha, A., Sawatzky, B., Shahinyan, A., Silwal, R., Singh, J., Sirca, S., Slifer, K., Snyder, R., Solvignon, P., Souder, P. A., Sperduto, M. L., Subedi, R., Stutzman, M. L., Suleiman, R., Sulkosky, V., Sutera, C. M., Tobias, W. A., Troth, W., Urciuoli, G. M., Ulmer, P., Vacheret, A., Voutier, E., Waidyawansa, B., Wang, D., Wang, K., Wexler, J., Whitbeck, A., Wilson, R., Wojtsekhowski, B., Yan, X., Yao, H., Ye, Y., Ye, Z., Yim, V., Zana, L., Zhan, X., Zhang, J., Zhang, Y., Zheng, X., Ziskin, V., and Zhu, P.

Subjects
Nuclear Experiment
Abstract

We have measured the beam-normal single-spin asymmetry $A_n$ in the elastic scattering of 1-3 GeV transversely polarized electrons from $^1$H and for the first time from $^4$He, $^{12}$C, and $^{208}$Pb. For $^1$H, $^4$He and $^{12}$C, the measurements are in agreement with calculations that relate $A_n$ to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the $^{208}$Pb result is significantly smaller than the corresponding prediction using the same formalism. These results suggest that a systematic set of new $A_n$ measurements might emerge as a new and sensitive probe of the structure of heavy nuclei., Comment: 5 pages, 3 figures, accepted by PRL. v3: fixed one author name and affiliation, otherwise no change

Published
2012
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19. Measurement of the Neutron Radius of 208Pb Through Parity-Violation in Electron Scattering

Author

Abrahamyan, S., Ahmed, Z., Albataineh, H., Aniol, K., Armstrong, D. S., 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, G. D., Chen, C., Chen, J. -P., Hen, O., Cusanno, F., Dalton, M. M., De Leo, R., de Jager, K., Deconinck, W., Decowski, P., Deng, X., Deur, A., Dutta, D., Etile, A., Flay, D., Franklin, G. B., 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, D. W., Holmes, R. S., Holmstrom, T., Horowitz, C. J., Hoskins, J., Huang, J., Hyde, C. E., Itard, F., Jen, C. -M., Jensen, E., Jin, G., Johnston, S., Kelleher, A., Kliakhandler, K., King, P. M., Kowalski, S., Kumar, K. S., Leacock, J., Leckey IV, J., Lee, J. H., LeRose, J. J., Lindgren, R., Liyanage, N., Lubinsky, N., Mammei, J., Mammoliti, F., Margaziotis, D. J., Markowitz, P., McCreary, A., McNulty, D., Mercado, L., Meziani, Z. -E., Michaels, R. W., Mihovilovic, M., Muangma, N., Muñoz-Camacho, C., Nanda, S., Nelyubin, V., Nuruzzaman, N., Oh, Y., Palmer, A., Parno, D., Paschke, K. D., Phillips, S. K., Poelker, B., Pomatsalyuk, R., Posik, M., Puckett, A. J. R., Quinn, B., Rakhman, A., Reimer, P. E., 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, P. A., Sperduto, M. L., Subedi, R., Suleiman, R., Sulkosky, V., Sutera, C. M., Tobias, W. A., Troth, W., Urciuoli, G. M., 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.

Subjects
Nuclear Experiment
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 (Rn). The result A_PV = 0.656 \pm 0.060 (stat) \pm 0.014 (syst) ppm corresponds to a difference between the radii of the neutron and proton distributions Rn - Rp = 0.33 +0.16 -0.18 fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus., Comment: 6 pages, 1 figure

Published
2012
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20. New Precision Limit on the Strange Vector Form Factors of the Proton

Author

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

Subjects
Nuclear Experiment
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 GeV and beam energy E =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 + 0.517 G_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., Comment: 5 pages, 3 figures

Published
2011
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21. The Qweak experimental apparatus

Author

Allison, T., Anderson, M., Androić, D., Armstrong, D.S., Asaturyan, A., Averett, T., Averill, R., Balewski, J., Beaufait, J., Beminiwattha, R.S., Benesch, J., Benmokhtar, F., Bessuille, J., Birchall, J., Bonnell, E., Bowman, J.D., Brindza, P., Brown, D.B., Carlini, R.D., Cates, G.D., Cavness, B., Clark, G., Cornejo, J.C., Dusa, S. Covrig, Dalton, M.M., Davis, C.A., Dean, D.C., Deconinck, W., Diefenbach, J., Dow, K., Dowd, J.F., Dunne, J.A., Dutta, D., Duvall, W.S., Echols, J.R., Elaasar, M., Falk, W.R., Finelli, K.D., Finn, J.M., Gaskell, D., Gericke, M.T.W., Grames, J., Gray, V.M., Grimm, K., Guo, F., Hansknecht, J., Harrison, D.J., Henderson, E., Hoskins, J.R., Ihloff, E., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., Kelsey, J., Khan, N., King, P.M., Korkmaz, E., Kowalski, S., Kubera, A., Leacock, J., Leckey, J.P., Lee, A.R., Lee, J.H., Lee, L., Liang, Y., MacEwan, S., Mack, D., Magee, J.A., Mahurin, R., Mammei, J., Martin, J.W., McCreary, A., McDonald, M.H., McHugh, M.J., Medeiros, P., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Musson, J., Mesick, K.E., Narayan, A., Ndukum, L.Z., Nelyubin, V., Nuruzzaman, van Oers, W.T.H., Opper, A.K., Page, S.A., Pan, J., Paschke, K.D., Phillips, S.K., Pitt, M.L., Poelker, M., Rajotte, J.F., Ramsay, W.D., Roberts, W.R., Roche, J., Rose, P.W., Sawatzky, B., Seva, T., Shabestari, M.H., Silwal, R., Simicevic, N., Smith, G.R., Sobczynski, S., Solvignon, P., Spayde, D.T., Stokes, B., Storey, D.W., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W.A., Tvaskis, V., Urban, E., Waidyawansa, B., Wang, P., Wells, S.P., Wood, S.A., Yang, S., Zhamkochyan, S., and Zielinski, R.B.

Published
2015
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22. The tracking analysis in the Q-weak experiment

Author

Pan, J., Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cates, G. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Myers, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H, Opper, A. K., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., and Zhamkochyan, S.

Published
2016
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23. Deeply Virtual Compton Scattering Cross Section at High Bjorken xB

Author

Georges, F., Rashad, M.N.H., Stefanko, A., Dlamini, M., Karki, B., Ali, S.F., Lin, P-J., Ko, H-S, Israel, N., Adikaram, D., Ahmed, Z., Albataineh, H., Aljawrneh, B., Allada, K., Allison, S., Alsalmi, S., Androic, D., Aniol, K., Annand, J., Atac, H., Averett, T., Ayerbe Gayoso, C., Bai, X., Bane, J., Barcus, S., Bartlett, K., Bellini, V., Beminiwattha, R., Bericic, J., Biswas, D., Brash, E., Bulumulla, D., Campbell, J., Camsonne, A., Carmignotto, M., Castellano, J., Chen, C., Chen, J-P., Chetry, T., Christy, M.E., Cisbani, E., Clary, B., Cohen, E., Compton, N., Cornejo, J.C., Dusa, S. Covrig, Crowe, B., Danagoulian, S., Danley, T., de Persio, F., Deconinck, W., Defurne, M., Desnault, C., Di, D., Duer, M., Duran, B., Ent, R., Fanelli, C., Franklin, G., Fuchey, E., Gal, C., Gaskell, D., Gautam, T., Glamazdin, O., Gnanvo, K., Gray, V.M., Gu, C., Hague, T., Hamad, G., Hamilton, D., Hamilton, K., Hansen, O., Hauenstein, F., Henry, W., Higinbotham, D.W., Holmstrom, T., Horn, T., Huang, Y., Huber, G.M., Hyde, C.E., Ibrahim, H., Jen, C-M., Jin, K., Jones, M., Kabir, A., Keppel, C., Khachatryan, V., King, P.M., Li, S., Li, W.B., Liu, J., Liu, H., Liyanage, A., Magee, J., Malace, S., Mammei, J., Markowitz, P., Mcclellan, E., Mazouz, M., Meddi, F., Meekins, D., Mesik, K., Michaels, R., Mkrtchyan, A., Montgomery, R., Muñoz Camacho, C., Myers, L.S., Nadel-Turonski, P., Nazeer, S.J., Nelyubin, V., Nguyen, D., Nuruzzaman, N., Nycz, M., Obretch, O.F., Ou, L., Palatchi, C., Pandey, B., Park, S., Park, K., Peng, C., Pomatsalyuk, R., Pooser, E., Puckett, A.J.R., Punjabi, V., Quinn, B., Rahman, S., Reimer, P.E., Roche, J., Sapkota, I., Sarty, A., Sawatzky, B., Saylor, N.H., Schmookler, B., Shabestari, M.H., Shahinyan, A., Sirca, S., Smith, G.R., Sooriyaarachchilage, S., Sparveris, N., Spies, R., Su, T., Subedi, A., Sulkosky, V., Sun, A., Thorne, L., Tian, Y., Ton, N., Tortorici, F., Trotta, R., Urciuoli, G.M., Voutier, E., Waidyawansa, B., Wang, Y., Wojtsekhowski, B., Wood, S., Yan, X., Ye, L., Ye, Z., Yero, C., Zhang, J., Zhao, Y., Zhu, P., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Jefferson Lab Hall A

Subjects
dimension: 3, parton: distribution function, FOS: Physical sciences, General Physics and Astronomy, Compton scattering: form factor, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucleon: generalized parton distribution, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], deep virtual Compton scattering, Compton form factor, helicity, Bjorken scaling, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, photon: final state
Abstract

International audience; We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable xB. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of xB, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

Published
2022

24. Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering

Author

Christy, M. E., primary, Gautam, T., additional, Ou, L., additional, Schmookler, B., additional, Wang, Y., additional, Adikaram, D., additional, Ahmed, Z., additional, Albataineh, H., additional, Ali, S. F., additional, Aljawrneh, B., additional, Allada, K., additional, Allison, S. L., additional, Alsalmi, S., additional, Androic, D., additional, Aniol, K., additional, Annand, J., additional, Arrington, J., additional, Atac, H., additional, Averett, T., additional, Ayerbe Gayoso, C., additional, Bai, X., additional, Bane, J., additional, Barcus, S., additional, Bartlett, K., additional, Bellini, V., additional, Beminiwattha, R., additional, Bericic, J., additional, Bhatt, H., additional, Bhetuwal, D., additional, Biswas, D., additional, Brash, E., additional, Bulumulla, D., additional, Camacho, C. M., additional, Campbell, J., additional, Camsonne, A., additional, Carmignotto, M., additional, Castellanos, J., additional, Chen, C., additional, Chen, J-P., additional, Chetry, T., additional, Cisbani, E., additional, Clary, B., additional, Cohen, E., additional, Compton, N., additional, Cornejo, J. C., additional, Covrig Dusa, S., additional, Crowe, B., additional, Danagoulian, S., additional, Danley, T., additional, Deconinck, W., additional, Defurne, M., additional, Desnault, C., additional, Di, D., additional, Dlamini, M., additional, Duer, M., additional, Duran, B., additional, Ent, R., additional, Fanelli, C., additional, Fuchey, E., additional, Gal, C., additional, Gaskell, D., additional, Georges, F., additional, Gilad, S., additional, Glamazdin, O., additional, Gnanvo, K., additional, Gramolin, A. V., additional, Gray, V. M., additional, Gu, C., additional, Habarakada, A., additional, Hague, T., additional, Hamad, G., additional, Hamilton, D., additional, Hamilton, K., additional, Hansen, O., additional, Hauenstein, F., additional, Hernandez, A. V., additional, Henry, W., additional, Higinbotham, D. W., additional, Holmstrom, T., additional, Horn, T., additional, Huang, Y., additional, Huber, G. M., additional, Hyde, C., additional, Ibrahim, H., additional, Israel, N., additional, Jen, C-M., additional, Jin, K., additional, Jones, M., additional, Kabir, A., additional, Karki, B., additional, Keppel, C., additional, Khachatryan, V., additional, King, P. M., additional, Li, S., additional, Li, W., additional, Liu, H., additional, Liu, J., additional, Liyanage, A. H., additional, Mack, D., additional, Magee, J., additional, Malace, S., additional, Mammei, J., additional, Markowitz, P., additional, Mayilyan, S., additional, McClellan, E., additional, Meddi, F., additional, Meekins, D., additional, Mesick, K., additional, Michaels, R., additional, Mkrtchyan, A., additional, Moffit, B., additional, Montgomery, R., additional, Myers, L. S., additional, Nadel-Turonski, P., additional, Nazeer, S. J., additional, Nelyubin, V., additional, Nguyen, D., additional, Nuruzzaman, N., additional, Nycz, M., additional, Obrecht, R. F., additional, Ohanyan, K., additional, Palatchi, C., additional, Pandey, B., additional, Park, K., additional, Park, S., additional, Peng, C., additional, Persio, F. D., additional, Pomatsalyuk, R., additional, Pooser, E., additional, Puckett, A. J. R., additional, Punjabi, V., additional, Quinn, B., additional, Rahman, S., additional, Rashad, M. N. H., additional, Reimer, P. E., additional, Riordan, S., additional, Roche, J., additional, Sapkota, I., additional, Sarty, A., additional, Sawatzky, B., additional, Saylor, N. H., additional, Shabestari, M. H., additional, Shahinyan, A., additional, Širca, S., additional, Smith, G. R., additional, Sooriyaarachchilage, S., additional, Sparveris, N., additional, Spies, R., additional, Stefanko, A., additional, Su, T., additional, Subedi, A., additional, Sulkosky, V., additional, Sun, A., additional, Tan, Y., additional, Thorne, L., additional, Ton, N., additional, Tortorici, F., additional, Trotta, R., additional, Uniyal, R., additional, Urciuoli, G. M., additional, Voutier, E., additional, Waidyawansa, B., additional, Wojtsekhowski, B., additional, Wood, S., additional, Yan, X., additional, Ye, L., additional, Ye, Z. H., additional, Yero, C., additional, Zhang, J., additional, Zhao, Y. X., additional, and Zhu, P., additional

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

Author

Androić, Darko, Armstrong, D. S., Bartlett, K., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Covrig Dusa, S., Dalton, M. M., Davis, C. A., Deconinck, W., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gal, C., Gaskell, D., Gericke, M. T. W., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Jones, D. C., Jones, M. K., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mesick, K. E., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H., Owen, V. F., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Radloff, R. W., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Ševa, Tomislav, Shabestari, M. H., Silwal, R., Šimičević, Neven, Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Zang, P., Zhamkochyan, S., Christy, M. E., Horowitz, C. J., Fattoyev, F. J., and Lin, Z.

Subjects
parity vialation, elastic electron scattering asimmetry, neuton skin thickness
Abstract

We report the first measurement of the parity- violating elastic electron scattering asymmetry on 27Al. The 27Al elastic asymmetry is A_PV = 2.16 +- 0.11 (stat) +- 0.16 (syst) ppm, and was measured at =0.02357 +- 0.0001 GeV^2, = 7.61 +- 0.02 degrees, and = 1.157 GeV with the Qweak 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 27Al neutron radius R_n = 2.89 +- 0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_n-R_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 27Al weak radius R_w = 3.00 +- 0.15 fm, and the weak skin thickness R_wk - R_ch = -0.04 +- 0.15 fm. The weak form factor at this Q^2 is F_wk = 0.39 +- 0.04.

Published
2021

26. The ${Q^{p}_{\rm Weak}}$ experiment: A search for physics beyond the standard model via a measurement of the proton’s weak charge

Author

Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dow, K., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J., McHugh, M., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Myers, K. E., Mkrtchyan, A., Mkrtchyan, H., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, N., van Oers, W. T. H, Opper, A. K., Page, S. A., Pan, J., Paschke, K., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., Zhamkochyan, S., and Zou, D.

Published
2013
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27. Deep Exclusive Electroproduction of π0 at High Q2 in the Quark Valence Regime

Author

The Jefferson Lab Hall A Collaboration, Dlamini, M., Karki, B., Ali, S. F., Lin, P-J., Georges, F., Ko, H-S, Israel, N., Rashad, M. N. H., Stefanko, A., Adikaram, D., Ahmed, Z., Albataineh, H., Aljawrneh, B., Allada, K., Allison, S., Alsalmi, S., Androic, D., Aniol, K., Annand, J., Atac, H., Averett, T., Gayoso, C. Ayerbe, Bai, X., Bane, J., Barcus, S., Bartlett, K., Bellini, V., Beminiwattha, R., Bericic, J., Biswas, D., Brash, E., Bulumulla, D., Campbell, J., Camsonne, A., Carmignotto, M., Castellano, J., Chen, C., Chen, J-P., Chetry, T., Christy, M. E., Cisbani, E., Clary, B., Cohen, E., Compton, N., Cornejo, J. C., Dusa, S. Covrig, Crowe, B., Danagoulian, S., Danley, T., De Persio, F., Deconinck, W., Defurne, M., Desnault, C., Di, D., Duer, M., Duran, B., Ent, R., Fanelli, C., Franklin, G., Fuchey, E., Gal, C., Gaskell, D., Gautam, T., Glamazdin, O., Gnanvo, K., Gray, V. M., Gu, C., Hague, T., Hamad, G., Hamilton, D., Hamilton, K., Hansen, O., Hauenstein, F., Henry, W., Higinbotham, D. W., Holmstrom, T., Horn, T., Huang, Y., Huber, G. M., Hyde, C., Ibrahim, H., Jen, C-M., Jin, K., Jones, M., Kabir, A., Keppel, C., Khachatryan, V., King, P. M., Li, S., Li, W., Liu, J., Liu, H., Liyanage, A., Magee, J., Malace, S., Mammei, J., Markowitz, P., McClellan, E., Meddi, F., Meekins, D., Mesik, K., Michaels, R., Mkrtchyan, A., Montgomery, R., Camacho, C. Munoz, Myers, L. S., Nadel-Turonski, P., Nazeer, S. J., Nelyubin, V., Nguyen, D., Nuruzzaman, N., Nycz, M., Obretch, O. F., Ou, L., Palatchi, C., Pandey, B., Park, S., Park, K., Peng, C., Pomatsalyuk, R., Pooser, E., Puckett, A. J. R., Punjabi, V., Quinn, B., Rahman, S., Reimer, P. E., Roche, J., Sapkota, I., Sarty, A., Sawatzky, B., Saylor, N. H., Schmookler, B., Shabestari, M. H., Shahinyan, A., Sirca, S., Smith, G. R., Sooriyaarachchilage, S., Sparveris, N., Spies, R., Su, T., Subedi, A., Sulkosky, V., Sun, A., Thorne, L., Tian, Y., Ton, N., Tortorici, F., Trotta, R., Urciuoli, G. M., Voutier, E., Waidyawansa, B., Wang, Y., Wojtsekhowski, B., Wood, S., Yan, X., Ye, L., Ye, Z., Yero, C., Zhang, J., Zhao, Y., Zhu, P., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Jefferson Lab Hall A

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], momentum transfer dependence, helicity, High Energy Physics - Experiment, pi: distribution amplitude, generalized parton distribution: transversity, kinematics, pi0: electroproduction, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], quark: valence, polarization: transverse, High Energy Physics::Experiment, p: structure function, Nuclear Experiment, experimental results, photon: virtual, Jefferson Lab
Abstract

International audience; We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of xB (0.36, 0.48, and 0.60) and Q2 (3.1 to 8.4 GeV2) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσT/dt+εdσL/dt, dσTT/dt, dσLT/dt, and dσLT′/dt are extracted as a function of the proton momentum transfer t-tmin. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Published
2021

28. Measurement of parity violation in electron–quark scattering

Author

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

Published
2014
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29. Parity-violating inelastic electron-proton scattering at low Q2 above the resonance region

Author

Androić, D., Armstrong, D. S., Asaturyan, A., Bartlett, K., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cornejo, J. C., Covrig Dusa, S., Dalton, M. M., Davis, C. A., Deconinck, W., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Gal, C., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Jones, D., Jones, M. K., Jones, R. T., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J. P., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mesick, K. E., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Narayan, A., Ndukum, L. Z., Nelyubin, V., van Oers, W. T. H., Owen, V. F., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Radloff, R. W., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Suleiman, R., Tadevosyan, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Zang, P., and Qweak Collaboration

Subjects
three-body breakup, reaction cross section, helium-3, Photon, media_common.quotation_subject, Nuclear Theory, FOS: Physical sciences, Electron, Inelastic scattering, 01 natural sciences, Asymmetry, Nuclear physics, High Energy Physics - Phenomenology (hep-ph), Proton scattering, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, media_common, Physics, Elastic scattering, 010308 nuclear & particles physics, Structure function, Parity (physics), NATURAL SCIENCES. Physics, PRIRODNE ZNANOSTI. Fizika, High Energy Physics - Phenomenology, High Energy Physics::Experiment
Abstract

We report the measurement of the parity-violating asymmetry for the inelastic scattering of electrons from the proton, at $Q^2 = 0.082$ GeV$^2$ and $ W = 2.23$ GeV, above the resonance region. The result $A_{\rm Inel} = - 13.5 \pm 2.0 ({\rm stat}) \pm 3.9 ({\rm syst})$~ppm agrees with theoretical calculations, and helps to validate the modeling of the $\gamma Z$ interference structure functions $F_1^{\gamma Z}$ and $F_2^{\gamma Z}$ used in those calculations, which are also used for determination of the two-boson exchange box diagram ($\Box_{\gamma Z}$) contribution to parity-violating elastic scattering measurements. A positive parity-violating asymmetry for inclusive $\pi^-$ production was observed, as well as positive beam-normal single-spin asymmetry for scattered electrons and a negative beam-normal single-spin asymmetry for inclusive $\pi^-$ production., Comment: 18 pages, 9 figures, version accepted in Physical Review C

Published
2020

30. The ${Q^{p}_{\rm Weak}}$ experiment

Author

Androic, D., primary, Armstrong, D. S., additional, Asaturyan, A., additional, Averett, T., additional, Balewski, J., additional, Beaufait, J., additional, Beminiwattha, R. S., additional, Benesch, J., additional, Benmokhtar, F., additional, Birchall, J., additional, Carlini, R. D., additional, Cornejo, J. C., additional, Covrig, S., additional, Dalton, M. M., additional, Davis, C. A., additional, Deconinck, W., additional, Diefenbach, J., additional, Dow, K., additional, Dowd, J. F., additional, Dunne, J. A., additional, Dutta, D., additional, Duvall, W. S., additional, Elaasar, M., additional, Falk, W. R., additional, Finn, J. M., additional, Forest, T., additional, Gaskell, D., additional, Gericke, M. T. W., additional, Grames, J., additional, Gray, V. M., additional, Grimm, K., additional, Guo, F., additional, Hoskins, J. R., additional, Johnston, K., additional, Jones, D., additional, Jones, M., additional, Jones, R., additional, Kargiantoulakis, M., additional, King, P. M., additional, Korkmaz, E., additional, Kowalski, S., additional, Leacock, J., additional, Leckey, J., additional, Lee, A. R., additional, Lee, J. H., additional, Lee, L., additional, MacEwan, S., additional, Mack, D., additional, Magee, J. A., additional, Mahurin, R., additional, Mammei, J., additional, Martin, J., additional, McHugh, M., additional, Meekins, D., additional, Mei, J., additional, Michaels, R., additional, Micherdzinska, A., additional, Myers, K. E., additional, Mkrtchyan, A., additional, Mkrtchyan, H., additional, Narayan, A., additional, Ndukum, L. Z., additional, Nelyubin, V., additional, Nuruzzaman, N., additional, van Oers, W. T. H, additional, Opper, A. K., additional, Page, S. A., additional, Pan, J., additional, Paschke, K., additional, Phillips, S. K., additional, Pitt, M. L., additional, Poelker, M., additional, Rajotte, J. F., additional, Ramsay, W. D., additional, Roche, J., additional, Sawatzky, B., additional, Seva, T., additional, Shabestari, M. H., additional, Silwal, R., additional, Simicevic, N., additional, Smith, G., additional, Solvignon, P., additional, Spayde, D. T., additional, Subedi, A., additional, Subedi, R., additional, Suleiman, R., additional, Tadevosyan, V., additional, Tobias, W. A., additional, Tvaskis, V., additional, Waidyawansa, B., additional, Wang, P., additional, Wells, S. P., additional, Wood, S. A., additional, Yang, S., additional, Young, R. D., additional, Zhamkochyan, S., additional, and Zou, D., additional

Published
2013
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31. A novel comparison of Møller and Compton electron-beam polarimeters

Author

Magee, J.A., Narayan, A., Jones, D., Beminiwattha, R., Cornejo, J.C., Dalton, M.M., Deconinck, W., Dutta, D., Gaskell, D., Martin, J.W., Paschke, K.D., Tvaskis, V., Asaturyan, A., Benesch, J., Cates, G., Cavness, B.S., A. Dillon-Townes, L., Hays, G., Hoskins, J., Ihloff, E., Jones, R., King, P.M., Kowalski, S., Kurchaninov, L., Lee, L., McCreary, A., McDonald, M., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Nelyubin, V., Page, S., Ramsay, W.D., Solvignon, P., Storey, D., Tobias, W.A., Urban, E., Vidal, C., Waidyawansa, B., Wang, P., and Zhamkotchyan, S.

Published
2017
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32. First Direct Measurement of the Proton’s Weak Charge

Author

Androić, Darko, Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Bartlett, K., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cates, G. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvalla, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gal, C., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, J., Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Myers, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuhait, H., Nuruzzaman, W.T.H van Oers, Page, S. A., Opper, A. K., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Ševa, Tomislav, Shabestari, M. H., Silwal, R., Šimičević, Neven, Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., Zang, P., and Zhamkochyan, S.

Subjects
PRIRODNE ZNANOSTI. Fizika, q-weak experiment, Nuclear Experiment, NATURAL SCIENCES. Physics
Abstract

The Qweak experiment, which took data at Jefferson Lab in the period 2010 - 2012, will precisely determine the weak charge of the proton by measuring the parity-violating asymmetry in elastic e-p scattering at 1.1 GeV using a longitudinally polarized electron beam and a liquid hydrogen target at a low momentum transfer of Q2 = 0.025 (GeV/c)2. The weak charge of the proton is predicted by the Standard Model and any significant deviation would indicate physics beyond the Standard Model. The technical challenges and experimental apparatus for measuring the weak charge of the proton will be discussed, as well as the method of extracting the weak charge of the proton. The results from a small subset of the data, that has been published, will also be presented. Furthermore an update will be given of the current status of the data analysis.

Published
2017

33. Precision Electron-Beam Polarimetry at 1 GeV Using Diamond Microstrip Detectors

Author

Narayan, A., primary, Jones, D., additional, Cornejo, J. C., additional, Dalton, M. M., additional, Deconinck, W., additional, Dutta, D., additional, Gaskell, D., additional, Martin, J. W., additional, Paschke, K. D., additional, Tvaskis, V., additional, Asaturyan, A., additional, Benesch, J., additional, Cates, G., additional, Cavness, B. S., additional, Dillon-Townes, L. A., additional, Hays, G., additional, Ihloff, E., additional, Jones, R., additional, King, P. M., additional, Kowalski, S., additional, Kurchaninov, L., additional, Lee, L., additional, McCreary, A., additional, McDonald, M., additional, Micherdzinska, A., additional, Mkrtchyan, A., additional, Mkrtchyan, H., additional, Nelyubin, V., additional, Page, S., additional, Ramsay, W. D., additional, Solvignon, P., additional, Storey, D., additional, Tobias, A., additional, Urban, E., additional, Vidal, C., additional, Waidyawansa, B., additional, Wang, P., additional, and Zhamkotchyan, S., additional

Published
2016
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34. Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering

Author

Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Bertozzi, William, Deconinck, Wouter, Pan, Kai, Gilad, Shalev, Huang, Jin, Kowalski, Stanley B., Muangma, Navaphon, Sulkosky, Vincent, Wang, D., Subedi, R., Ahmed, Z., Allada, Kalyan C., Aniol, K., Armstrong, D. S., Arrington, J., Bellini, V., Beminiwattha, R., Benesch, J., Benmokhtar, F., Camsonne, A., Canan, M., Cates, G. D., Chen, J.-P., Chudakov, E., Cisbani, E., Dalton, M. M., de Jager, C. W., De Leo, R., Deng, X., Deur, A., Dutta, C., Fassi, L. El, Erler, J., Flay, D., Franklin, G. B., Friend, M., Frullani, S., Garibaldi, F., Giusa, A., Glamazdin, A., Golge, S., Grimm, K., Hafidi, K., Hansen, J.-O., Higinbotham, D. W., Holmes, R., Holmstrom, T., Holt, R. J., Hyde, C. E., Jen, C. M., Jones, D., Kang, Hoyoung, King, P. M., Kumar, K. S., Lee, J. H., LeRose, J. J., Liyanage, N., Long, E., McNulty, D., Margaziotis, D. J., Meddi, F., Meekins, D. G., Mercado, L., Meziani, Z.-E., Michaels, R., Mihovilovic, M., Mesick, K. E., Nanda, S., Narayan, A., Nelyubin, V., Nuruzzaman, N., Oh, Y., Parno, D., Paschke, K. D., Phillips, S. K., Qian, X., Qiang, Y., Quinn, B., Rakhman, A., Reimer, P. E., Rider, K., Riordan, S., Roche, J., Rubin, J., Russo, G., Saenboonruang, K., Saha, A., Sawatzky, B., Shahinyan, A., Silwal, R., Širca, S., Souder, P. A., Suleiman, R., Sutera, C. M., Tobias, W. A., Urciuoli, G. M., Waidyawansa, B., Wojtsekhowski, B., Ye, L., Zhao, B., Zheng, X., Kowalski, Stanley B, Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Bertozzi, William, Deconinck, Wouter, Pan, Kai, Gilad, Shalev, Huang, Jin, Kowalski, Stanley B., Muangma, Navaphon, Sulkosky, Vincent, Wang, D., Subedi, R., Ahmed, Z., Allada, Kalyan C., Aniol, K., Armstrong, D. S., Arrington, J., Bellini, V., Beminiwattha, R., Benesch, J., Benmokhtar, F., Camsonne, A., Canan, M., Cates, G. D., Chen, J.-P., Chudakov, E., Cisbani, E., Dalton, M. M., de Jager, C. W., De Leo, R., Deng, X., Deur, A., Dutta, C., Fassi, L. El, Erler, J., Flay, D., Franklin, G. B., Friend, M., Frullani, S., Garibaldi, F., Giusa, A., Glamazdin, A., Golge, S., Grimm, K., Hafidi, K., Hansen, J.-O., Higinbotham, D. W., Holmes, R., Holmstrom, T., Holt, R. J., Hyde, C. E., Jen, C. M., Jones, D., Kang, Hoyoung, King, P. M., Kumar, K. S., Lee, J. H., LeRose, J. J., Liyanage, N., Long, E., McNulty, D., Margaziotis, D. J., Meddi, F., Meekins, D. G., Mercado, L., Meziani, Z.-E., Michaels, R., Mihovilovic, M., Mesick, K. E., Nanda, S., Narayan, A., Nelyubin, V., Nuruzzaman, N., Oh, Y., Parno, D., Paschke, K. D., Phillips, S. K., Qian, X., Qiang, Y., Quinn, B., Rakhman, A., Reimer, P. E., Rider, K., Riordan, S., Roche, J., Rubin, J., Russo, G., Saenboonruang, K., Saha, A., Sawatzky, B., Shahinyan, A., Silwal, R., Širca, S., Souder, P. A., Suleiman, R., Sutera, C. M., Tobias, W. A., Urciuoli, G. M., Waidyawansa, B., Wojtsekhowski, B., Ye, L., Zhao, B., Zheng, X., and Kowalski, Stanley B

Abstract

The parity-violating asymmetries between a longitudinally polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep-inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.

Published
2015

35. The Q[superscript p][subscript Weak] experiment

Author

Androic, D., Armstrong, D. S, Asaturyan, A., Averett, T., Beaufait, J., Beminiwattha, R. S, Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D, Cornejo, J. C, Covrig, S., Dalton, M. M, Davis, C. A, Deconinck, W., Diefenbach, J., Dowd, J. F, Dunne, J. A, Dutta, D., Duvall, W. S, Elaasar, M., Falk, W. R, Finn, J. M, Forest, T., Gaskell, D., Gericke, M. T W, Grames, J., Gray, V. M, Grimm, K., Hoskins, J. R, Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M, Korkmaz, E., Leacock, J., Leckey, J., Lee, A. R, Lee, J. H, Lee, L., MacEwan, S., Mack, D., Magee, J. A, Mahurin, R., Mammei, J., Martin, J., McHugh, M., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Myers, K. E, Mkrtchyan, A., Mkrtchyan, H., Narayan, A., Ndukum, L. Z, Nelyubin, V., Nuruzzaman, N., van Oers, W. T H, Opper, A. K, Page, S. A, Pan, J., Paschke, K., Phillips, S. K, Pitt, M. L, Poelker, M., Ramsay, W. D, Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H, Silwal, R., Simicevic, N., Smith, G., Solvignon, P., Spayde, D. T, Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A, Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P, Wood, S. A, Yang, S., Young, R. D, Zhamkochyan, S., Balewski, Jan T., Dow, Karen Ann, Guo, Fang, Kowalski, Stanley B, Rajotte, Jean-Francois, Zou, David, Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Balewski, Jan T., Dow, Karen Ann, Guo, Fang, Kowalski, Stanley B, Rajotte, Jean-Francois, and Zou, David

Abstract

In May 2012, the Q[superscript p][subscript Weak] collaboration completed a two year measurement program to determine the weak charge of the proton Q[superscript p][subscript Weak] = ( 1 - 4sin [superscript 2] θ[subscript W] at the Thomas Jefferson National Accelerator Facility (TJNAF). The experiment was designed to produce a 4.0 % measurement of the weak charge, via a 2.5 % measurement of the parity violating asymmetry in the number of elastically scattered 1.165 GeV electrons from protons, at forward angles. At the proposed precision, the experiment would produce a 0.3 % measurement of the weak mixing angle at a momentum transfer of Q[superscript 2] = 0.026 GeV[superscript 2], making it the most precise stand alone measurement of the weak mixing angle at low momentum transfer. In combination with other parity measurements, Q[superscript p][subscript Weak] will also provide a high precision determination of the weak charges of the up and down quarks. At the proposed precision, a significant deviation from the Standard Model prediction could be a signal of new physics at mass scales up to ≃ 6 TeV, whereas agreement would place new and significant constraints on possible Standard Model extensions at mass scales up to ≃ 2 TeV. This paper provides an overview of the physics and the experiment, as well as a brief look at some preliminary diagnostic and analysis data.

Published
2013

36. 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

37. First Determination of the Weak Charge of the Proton

Author

Physics, Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cates, G. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, John, Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Myers, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H., Opper, A. K., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., Zhamkochyan, S., Physics, Androic, D., Armstrong, D. S., Asaturyan, A., Averett, T., Balewski, J., Beaufait, J., Beminiwattha, R. S., Benesch, J., Benmokhtar, F., Birchall, J., Carlini, R. D., Cates, G. D., Cornejo, J. C., Covrig, S., Dalton, M. M., Davis, C. A., Deconinck, W., Diefenbach, J., Dowd, J. F., Dunne, J. A., Dutta, D., Duvall, W. S., Elaasar, M., Falk, W. R., Finn, J. M., Forest, T., Gaskell, D., Gericke, M. T. W., Grames, J., Gray, V. M., Grimm, K., Guo, F., Hoskins, J. R., Johnston, K., Jones, D., Jones, M., Jones, R., Kargiantoulakis, M., King, P. M., Korkmaz, E., Kowalski, S., Leacock, John, Leckey, J., Lee, A. R., Lee, J. H., Lee, L., MacEwan, S., Mack, D., Magee, J. A., Mahurin, R., Mammei, J., Martin, J. W., McHugh, M. J., Meekins, D., Mei, J., Michaels, R., Micherdzinska, A., Mkrtchyan, A., Mkrtchyan, H., Morgan, N., Myers, K. E., Narayan, A., Ndukum, L. Z., Nelyubin, V., Nuruzzaman, van Oers, W. T. H., Opper, A. K., Page, S. A., Pan, J., Paschke, K. D., Phillips, S. K., Pitt, M. L., Poelker, M., Rajotte, J. F., Ramsay, W. D., Roche, J., Sawatzky, B., Seva, T., Shabestari, M. H., Silwal, R., Simicevic, N., Smith, G. R., Solvignon, P., Spayde, D. T., Subedi, A., Subedi, R., Suleiman, R., Tadevosyan, V., Tobias, W. A., Tvaskis, V., Waidyawansa, B., Wang, P., Wells, S. P., Wood, S. A., Yang, S., Young, R. D., and Zhamkochyan, S.

Published
2013

38. 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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39. Deep Exclusive Electroproduction of π^{0} at High Q^{2} in the Quark Valence Regime.

Author

Dlamini M, Karki B, Ali SF, Lin PJ, Georges F, Ko HS, Israel N, Rashad MNH, Stefanko A, Adikaram D, Ahmed Z, Albataineh H, Aljawrneh B, Allada K, Allison S, Alsalmi S, Androic D, Aniol K, Annand J, Atac H, Averett T, Ayerbe Gayoso C, Bai X, Bane J, Barcus S, Bartlett K, Bellini V, Beminiwattha R, Bericic J, Biswas D, Brash E, Bulumulla D, Campbell J, Camsonne A, Carmignotto M, Castellano J, Chen C, Chen JP, Chetry T, Christy ME, Cisbani E, Clary B, Cohen E, Compton N, Cornejo JC, Covrig Dusa S, Crowe B, Danagoulian S, Danley T, De Persio F, Deconinck W, Defurne M, Desnault C, Di D, Duer M, Duran B, Ent R, Fanelli C, Franklin G, Fuchey E, Gal C, Gaskell D, Gautam T, Glamazdin O, Gnanvo K, Gray VM, Gu C, Hague T, Hamad G, Hamilton D, Hamilton K, Hansen O, Hauenstein F, Henry W, Higinbotham DW, Holmstrom T, Horn T, Huang Y, Huber GM, Hyde C, Ibrahim H, Jen CM, Jin K, Jones M, Kabir A, Keppel C, Khachatryan V, King PM, Li S, Li W, Liu J, Liu H, Liyanage A, Magee J, Malace S, Mammei J, Markowitz P, McClellan E, Meddi F, Meekins D, Mesik K, Michaels R, Mkrtchyan A, Montgomery R, Muñoz Camacho C, Myers LS, Nadel-Turonski P, Nazeer SJ, Nelyubin V, Nguyen D, Nuruzzaman N, Nycz M, Obretch OF, Ou L, Palatchi C, Pandey B, Park S, Park K, Peng C, Pomatsalyuk R, Pooser E, Puckett AJR, Punjabi V, Quinn B, Rahman S, Reimer PE, Roche J, Sapkota I, Sarty A, Sawatzky B, Saylor NH, Schmookler B, Shabestari MH, Shahinyan A, Sirca S, Smith GR, Sooriyaarachchilage S, Sparveris N, Spies R, Su T, Subedi A, Sulkosky V, Sun A, Thorne L, Tian Y, Ton N, Tortorici F, Trotta R, Urciuoli GM, Voutier E, Waidyawansa B, Wang Y, Wojtsekhowski B, Wood S, Yan X, Ye L, Ye Z, Yero C, Zhang J, Zhao Y, and Zhu P

Abstract

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x&#95;{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ&#95;{T}/dt+εdσ&#95;{L}/dt, dσ&#95;{TT}/dt, dσ&#95;{LT}/dt, and dσ&#95;{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t&#95;{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Published
2021
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40. 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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41. 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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42. 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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