GEp/GMp ratio by polarization transfer in (e)over-right-arrowp → e(p)over-right-arrow

The ratio of the proton's elastic electromagnetic form factors, G(Ep)/G(Mp), was obtained by measuring P-t and P-l, the transverse and the longitudinal recoil proton polarization, respectively For elastic (e) over right arrow p --> e (p) over right arrow, G(Ep)/G(Mp) is proportional to P-t/P-l. Simultaneous measurement of P-t and P-l in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G(Ep)/G(Mp) show a systematic decrease as Q(2) increases from 0.5 to 3.5 GeV2, indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the proton.