Measurement of the n-p Spin Correlation Parameter A yy at 50 MeV

Recent phase-shift fits to nucleon-nucleon scattering data have revealed that the phase parameter e1 is poorly determined for neutron-proton scattering near 50 MeV. Values of χ2, for the whole data set, show a nearly flat minimum when plotted against e1, apparently corresponding to solutions near e1 = −8° and 0° l). A measurement of the observable Ayy, would be valuable in determining the e1 parameter1). The only previous measurement of Ayy for neutron-proton scattering has been at 23 McV2).