Excitation functions of spin correlation parameters A_{NN}, A_{SS}, and A_{SL} in elastic pp scattering between 0.45 and 2.5 GeV

Abstract

Excitation functions of the spin correlation coefficients A_{NN}(p_{lab},theta_{c.m.}), A_{SS}(p_{lab},theta_{c.m.}), and A_{SL}(p_{lab},theta_{c.m.}) have been measured with the polarized proton beam of the Cooler Synchrotron COSY and an internal polarized atomic beam target. Data were taken continuously during the acceleration for proton momenta p_{lab} ranging from 1000 to 3300 MeV/c (kinetic energies T_{lab} 450 - 2500 MeV) as well as for discrete momenta of 1430 MeV/c and above 2000 MeV/c covering angles theta_{c.m.} between 30 deg and 90 deg. The data are of high internal consistency. Whereas A_{SL}(p_{lab,}theta_{c.m.}) is small and without structures in the whole range, A_{NN} and even more A_{SS} show a pronounced energy dependence. The angular distributions for A_{SS} are at variance with predictions of existing phase shift analyses at energies beyond 800 MeV. The impact of our results on phase shift solutions is discussed. The direct reconstruction of the scattering amplitudes from all available pp elastic scattering data considerably reduces the ambiguities of solutions.