Mean field deflection in peripheral heavy-ion collisions

We have measured the transverse momentum of protons as a function of rapidity in 50 MeV/nucleon C-induced peripheral collisions with C and Au targets. The reaction plane for each event was determined from the azimuthal angle of lightly damped coincident projectile fragments. High transverse momentum protons in the midrapidity region were found to be deflected towards the opposite side of the reaction plane with respect to the beam axis than the projectile fragments. This result is interpreted as projectile fragment scattering to positive angles due to the repulsive Coulomb interaction while midrapidity protons are simultaneously deflected to negative angles by the attractive component of the nuclear mean field.