This paper reports measurements of the analyzing power, $A_y$, in the production of both "backward" protons and forward (quasifree scattering) protons in the reaction $p+A\to p+X$, using 800-MeV polarized protons. For the backward protons the measurements show large negative $A$-dependent values of $A_y$ at low momenta, changing to large positive values at high momenta; in the quasielastic region, $A_y$ is large and positive, is smaller than $A_y$ measured in hydrogen, and decreases with increasing $A$.

• Received 3 October 1977

DOI:https://doi.org/10.1103/PhysRevLett.41.148