Unique Determination of Three Proton-Proton Scattering Parameters at 9.69 MeV

Abstract
The well-established fact that the spin-orbit interaction is of short range compared to one-pion-exchange (OPE) interaction causes the phase-shift combination ΔLS=(2δ1,03δ1,1+5δ1,2)12 to be small compared to ΔT=5(2δ1,03δ1,1+δ1,2)12 at low energy. We find that this makes it impossible to carry through an unambiguous phase-shift analysis of existing data near 10 MeV for δ0 and δ1,J, but it also makes it possible to show that the ratio ΔLSΔT must lie between 0.07 and 0.15 at 9.69 MeV. Using this result, we can then uniquely determine δ0E, ΔT, and ΔC=(δ1,0+3δ1,1+5δ1,2)9 and obtain δ0E=55.69°±0.28°, ΔT=0.91°±0.28°, ΔC=0.020°±0.029° with relative correlations (0T)=0.96, (0C)=0.47, (TC)=0.30. The result is stable against variation of ΔLSΔT over the full physically allowable range, against the extrapolation needed to include [AyyAxx](90°) at 11.4 MeV in the data set, against vacuum polarization corrections, and against whether or not phases with J>2, F23, and (marginally) ε2 are dropped or given their OPE values. The data require