Proton-proton analyzing power and spin correlation measurements between 250 and 450 MeV at7°<~θc.m.<~90°with an internal target in a storage ring

We have measured the $\mathrm{pp}$ spin correlation coefficients $A_{\mathrm{xx}},$ $A_{\mathrm{yy}},$ $A_{\mathrm{xz}}$ and the analyzing power $A_y$ at 250.0, 280.0, 294.4, 310.0, 350.0, 399.1, and 448.9 MeV over the laboratory angular range $3.5°–43.5°$ $({\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=7\mathrm{}°–90°).\mathrm{}$ The statistical accuracy is approximately $\pm 0.006$ for $A_y$ and $\pm 0.02$ for $A_{\mathrm{mn}}$ per $1°$ angle bin, while the corresponding scale factor uncertainties are 1.3 and 2.5 %, respectively. The experiment makes use of a polarized hydrogen gas target internal to a proton storage ring (IUCF Cooler) and a circulating beam of polarized protons. The method of calibration relative to pp spin correlation coefficients and analyzing power at 197.4 MeV, the injection energy, involves up and down ramping of the energy of the polarized beam. The data are compared to recent $\mathrm{pp}$ partial waves analyses and $\mathrm{NN}$ potential models, emphasizing in particular the energy dependence in the region of the pion production threshold.