Measurement of the depolarization parameter D in elastic 9Be(p,p) scattering

The depolarization parameter D has been measured for the 9Be(p,p) reaction at 225 MeV bombarding energy, for the laboratory angles of 22.4°, 30°, 40°, and 50°. The results show that D deviates from unity, and hence demonstrate the need for a spin‐spin term in the optical potential.