Search For Effects Beyond The Born Approximation In Polarization Transfer Observables In (E)Over-Right-Arrow P Elastic Scattering

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 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((e) over right arrow, e' (p) over right arrow) reaction for three different beam energies at a Q(2) = 2: 5 GeV2, spanning a wide range of the kinematic parameter epsilon. The ratio R, which equals mu(p)G(E)/G(M) in the Born approximation, is found to be independent of epsilon at the 1.5% level. The epsilon dependence of the longitudinal polarization transfer component P-l shows an enhancement of (2.3 +/- 0.6)% relative to the Born approximation at large epsilon