Proton Form Factor Ratio, $μ_p G_E^p/G_M^p$ from Double Spin Asymmetry

Academic Article

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.
  • Authors

  • 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, AM
  • 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, YM
  • Hashimoto, O
  • Higinbotham, D
  • Horn, T
  • Huber, GM
  • Jones, M
  • Jones, MK
  • Kalantarians, N
  • Kang, H-K
  • Kawama, D
  • Keppel, C
  • Khandaker, M
  • Kim, Y
  • King, PM
  • Kohl, M
  • Kovacs, K
  • Kubarovsky, V
  • Li, Y
  • Liyanage, N
  • Mamyan, V
  • Markowitz, P
  • Maruta, T
  • Melnik, YM
  • Meziani, Z-E
  • Mkrtchyan, A
  • Mkrtchyan, H
  • Mochalov, VV
  • Monaghan, P
  • Narayan, A
  • Nakamura, SN
  • Nuruzzaman
  • Pentchev, L
  • Pocanic, D
  • Posik, M
  • Puckett, A
  • Qiu, X
  • Reinhold, J
  • Riordan, S
  • Roche, J
  • Rondo'n, OA
  • Sawatzky, B
  • Shabestari, M
  • Slifer, Karl
  • Smith, G
  • Soloviev, LF
  • Solvignon, P
  • Tadevosyan, V
  • Tang, L
  • Vasiliev, AN
  • Veilleux, M
  • Walton, T
  • Wesselmann, F
  • Wood, SA
  • Yao, H
  • Ye, Z
  • Zhu, L
  • Publication Date

  • 2018
  • Keywords

  • nucl-ex