FIRST MEASUREMENT OF THE POLARIZATION TRANSFER ON THE PROTON IN THE REACTIONS H((E)OVER-RIGHT-ARROW,E'(P)OVER-RIGHT-ARROW) AND D((E)OVER-RIGHT-ARROW,E'(P)OVER-RIGHT-ARROW)

The measurement of the polarisation transfer to the proton in the reac tions H(($) over right arrow e,e'($) over right arrow P) and D(($) ove r right arrow e,e'($) over right arrow P) performed with longitudinall y polarised electrons in quasi-free kinematics is presented. The coinc idence measurement was executed at Q(2) approximate to 8 fm(-2) using the 855 MeV, c.w. beam of the Mainz Microtron MAMI. The recoil polaris ation was determined by means of a carbon analyser. The experiment sho ws that the binding of the nucleon does not modify the polarisation P- x of the recoil proton within an error of Delta P-x/P-x approximate to 10%. The measured polarisation agrees with recent theoretical predict ions. Implications for the measurement of the electric form factor of the neutron using the D(($) over right arrow e,e'($) over right arrow n) reaction are discussed.