1. Proton Form Factor Ratio, $\mu_p G_E^p/G_M^p$ from Double Spin Asymmetry
- Author
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Liyanage, A., Armstrong, W., Kang, H., Maxwell, J., Mulholland, J., Ndukum, L., Ahmidouch, A., Albayrak, I., Asaturyan, A., Ates, O., Baghdasaryan, H., Boeglin, W., Bosted, P., Brash, E., Butuceanu, C., Bychkov, M., Carter, P., Chen, C., Chen, J-P., Choi, S., Christy, E., Covrig, S., Crabb, D., Danagoulian, S., Daniel, A., Davidenko, A. M., Davis, B., Day, D., Deconinck, W., Deur, A., Dunne, J., Dutta, D., Fassi, L. El, Elaasar, M., Ellis, C., Ent, R., Flay, D., Frlez, E., Gaskell, D., Geagla, O., German, J., Gilman, R., Gogami, T., Gomez, J., Goncharenko, Y. M., Hashimoto, O., Higinbotham, D., Horn, T., Huber, G. M., Jones, M., Jones, M. K., Kalantarians, N., Kang, H-K., Kawama, D., Keppel, C., Khandaker, M., Kim, Y., King, P. M., Kohl, M., Kovacs, K., Kubarovsky, V., Li, Y., Liyanage, N., Mamyan, V., Markowitz, P., Maruta, T., Melnik, Y. M., Meziani, Z-E., Mkrtchyan, A., Mkrtchyan, H., Mochalov, V. V., Monaghan, P., Narayan, A., Nakamura, S. N., Nuruzzaman, Pentchev, L., Pocanic, D., Posik, M., Puckett, A., Qiu, X., Reinhold, J., Riordan, S., Roche, J., Rondo'n, O. A., Sawatzky, B., Shabestari, M., Slifer, K., Smith, G., Soloviev, L. F., Solvignon, P., Tadevosyan, V., Tang, L., Vasiliev, A. N., Veilleux, M., Walton, T., Wesselmann, F., Wood, S. A., Yao, H., Ye, Z., and Zhu, L.
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Nuclear Experiment - Abstract
The ratio of the electric and magnetic form factor of the proton, $\mu_p G_E^p/G_M^p$, has been measured for elastic electron-proton scattering with polarized beam and target up to four-momentum transfer squared, $Q^2=5.66$ (GeV/c)$^2$ using the double spin asymmetry for target spin orientation aligned nearly perpendicular to the beam momentum direction. This measurement of $\mu_p G_E^p/G_M^p$ agrees with the $Q^2$ dependence of previous recoil polarization data and reconfirms the discrepancy at high $Q^2$ between the Rosenbluth and the polarization-transfer method with a different measurement technique and systematic uncertainties uncorrelated to those of the recoil-polarization measurements. The form factor ratio at $Q^2$=2.06 (GeV/c)$^2$ has been measured as $\mu_p G_E^p/G_M^p = 0.720 \pm 0.176_{stat} \pm 0.039_{sys}$, which is in agreement with an earlier measurement with the polarized target technique at similar kinematics. The form factor ratio at $Q^2$=5.66 (GeV/c)$^2$ has been determined as $\mu_p G_E^p/G_M^p=0.244\pm0.353_{stat}\pm0.013_{sys}$, which represents the highest $Q^2$ reach with the double spin asymmetry with polarized target to date.
- Published
- 2018
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