Search for effects beyond the Born approximation in polarization transfer observables in $\vec{e}p$ elastic scattering
Creators: name: Meziane, M.
name: Brash, E. J.
name: Gilman, R.
name: Jones, M. K.
name: Luo, W.
name: Pentchev, L.
name: Perdrisat, C. F.
name: Puckett, A. J. R.
name: Punjabi, V.
name: Wesselmann, F. R.
name: Ahmidouch, A.
name: Albayrak, I.
name: Aniol, K. A.
name: Arrington, J.
name: Asaturyan, A.
name: Ates, O.
name: Baghdasaryan, H.
name: Benmokhtar, F.
name: Bertozzi, W.
name: Bimbot, L.
name: Bosted, P.
name: Boeglin, W.
name: Butuceanu, C.
name: Carter, P.
name: Chernenko, S.
name: Christy, E.
name: Commisso, M.
name: Cornejo, J. C.
name: Covrig, S.
name: Danagoulian, S.
name: Daniel, A.
name: Davidenko, A.
name: Day, D.
name: Dhamija, S.
name: Dutta, D.
name: Ent, R.
name: Frullani, S.
name: Fenker, H.
name: Frlez, E.
name: Garibaldi, F.
name: Gaskell, D.
name: Gilad, S.
name: Goncharenko, Y.
name: Hafidi, K.
name: Hamilton, D.
name: Higinbotham, D. W.
name: Hinton, W.
name: Horn, T.
name: Hu, B.
name: Huang, J.
name: Huber, G. M.
name: Jensen, E.
name: Kang, H.
name: Keppel, C.
name: Khandaker, M.
name: King, P.
name: Kirillov, D.
name: Kohl, M.
name: Kravtsov, V.
name: Kumbartzki, G.
name: Li, Y.
name: Mamyan, V.
name: Margaziotis, D. J.
name: Markowitz, P.
name: Marsh, A.
name: Matulenko, Y.
name: Maxwell, J.
name: Mbianda, G.
name: Meekins, D.
name: Melnik, Y.
name: Miller, J.
name: Mkrtchyan, A.
name: Mkrtchyan, H.
name: Moffit, B.
name: Moreno, O.
name: Mulholland, J.
name: Narayan, A.
name: Nuruzzaman
name: Nedev, S.
name: Piasetzky, E.
name: Pierce, W.
name: Piskunov, N. M.
name: Prok, Y.
name: Ransome, R. D.
name: Razin, D. S.
name: Reimer, P. E.
name: Reinhold, J.
name: Rondon, O.
name: Shabestari, M.
name: Shahinyan, A.
name: Shestermanov, K.
name: Sirca, S.
name: Sitnik, I.
name: Smykov, L.
name: Smith, G.
name: Solovyev, L.
name: Solvignon, P.
name: Subedi, R.
name: Suleiman, R.
name: Tomasi-Gustafsson, E.
name: Vasiliev, A.
name: Vanderhaeghen, M.
name: Veilleux, M.
name: Wojtsekhowski, B. B.
name: Wood, S.
name: Ye, Z.
name: Zanevsky, Y.
name: Zhang, X.
name: Zhang, Y.
name: Zheng, X.
name: Zhu, L.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, $G_{E}/G_{M}$, obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange (TPEX) contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic $H(\vec{e},e'\vec{p})$ reaction for three different beam energies at a fixed squared momentum transfer $Q^2 = 2.5$ GeV$^2$, spanning a wide range of the virtual photon polarization parameter, $ε$. From these measured polarization observables, we have obtained separately the ratio $R$, which equals $μ_p G_{E}/G_{M}$ in the Born approximation, and the longitudinal polarization transfer component $P_\ell$, with statistical and systematic uncertainties of $ΔR \approx \pm 0.01 \mbox{(stat)} \pm 0.013 \mbox{(syst)}$ and $ΔP_\ell/P^{Born}_{\ell} \approx \pm 0.006 \mbox{(stat)}\pm 0.01 \mbox{(syst)}$. The ratio $R$ is found to be independent of $ε$ at the 1.5% level, while the $ε$ dependence of $P_\ell$ shows an enhancement of $(2.3 \pm 0.6) %$ relative to the Born approximation at large $ε$.