Measurement of GEp/GMp via polarization transfer at Q2=0.4 GeV/c2

The polarization transfer from longitudinally polarized electrons to protons in the elastic scattering p((e) over right arrow, e' (p) over right arrow) has been measured around Q(2) = 0.4 (GeV/c)(2) with the three-spectrometer facility at the Mainz microtron MAMI. From this polarization transfer the ratio G(Ep)/(G(Mp)/mu (rho)) has been determined. The ratio is found to be slightly less than unity in agreement with recent results from other laboratories and from the Rosenbluth separation of cross-sections measured with unpolarized electrons.