Measurements of the Wolfenstein R and R′ parameters in proton-proton scattering at 98 MeV

Abstract

Measurements have been made of the Wolfenstein R parameter at c.m. angles 31.3, 41.6, 51.7, 61.9 and 72.0 degrees. The values obtained were −0.22±0.11, −0.40±0.10, −0.39±0.09, −0.12±0.13 and −0.18±0.20, respectively. Measurements have also been made of the R′ parameter at c.m. angles 31.6, 41.9, 52.0 and 62.6 degrees. The values obtained for R′ were 0.59±0.23, 0.66±0.18, 0.70±0.18 and 0.52±0.30 respectively. The R′ values were deduced from asymmetry measurements which were proportional to the combination ( R cos θ s + R′ sin θ s) of the R and R′ parameters, where the spin precession angle θ s was approximately 45°, so that it has been necessary to use the above values for R in order to obtain these R′ values.