Angular distribution of the longitudinal p→p→ spin correlation parameter Azz at 197.4 MeV

A polarized proton beam with a large longitudinal polarization component of 0.545 +/- 0.005 (96% of the total polarization) was prepared in a storage ring (IUCF-Cooler). This was achieved by means of spin precession solenoids in two of the six straight sections of the ring. A polarized hydrogen storage cell target internal to the ring was used to measure the longitudinal spin correlation coefficient A(zz) in pp elastic scattering over the laboratory angular range 5.5 degrees-43.5 degrees (theta(c.m.)=11.5 degrees-90 degrees) with statistical errors of typically 0.025. The absolute normalization was determined to an accuracy of 2.0% by use of the identity A(vy)-A(xx)--A(zz)=1 at theta(c.m.) = 90 degrees. The identity also allows a reduction of the scale factor uncertainty of the previously published analyzing powers and spin correlation coefficients. The results are compared to recent pp partial wave analyses and NN potential models.