Observation of narrow structures in thep-pelastic analyzing power

The momentum dependence of the analyzing power ${\mathit{A}}_{\mathit{y}}$ in proton-proton elastic scattering has been measured in small steps using an internal target during polarized beam acceleration from 1 to 3 GeV/c. The momentum bin size ranges from 5 to 18 MeV/c. The relative uncertainty of ${\mathit{A}}_{\mathit{y}}$ is typically less than 0.01 for each momentum bin. Narrow structures have been found in the two-proton invariant mass distribution of ${\mathit{A}}_{\mathit{y}}$.