Search for effects beyond the born approximation in polarization transfer observables in e(overâ)p elastic scattering.
Phys Rev Lett
; 106(13): 132501, 2011 Apr 01.
Article
en En
| MEDLINE
| ID: mdl-21520982
ABSTRACT
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 â],e(')p[over â]) reaction for three different beam energies at a Q(2)=2.5 GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals µ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(â) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.
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Banco de datos:
MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Año:
2011
Tipo del documento:
Article
País de afiliación:
Estados Unidos