Induced Polarization in the $^2$H($\gamma,\vec n$)$^1$H Reaction at Low Energy

Abstract

The induced polarization, $P^\prime_y$, of the neutron in the deuteron photo-disintegration from threshold up to 30 MeV is calculated using a variety of different, latest-generation potentials--Argonne $v_{18}$, Bonn 2000, and Nijmegen I-- and a realistic model for the nuclear electromagnetic current operator, including one- and two-body terms. The model dependence of the theoretical predictions is found to be very small. These predictions are systematically larger in magnitude than the measured $P^\prime_y$ values, and corroborate the conclusions of an earlier, and much older, study. There is considerable scatter in the available experimental data. New and more accurate measurements of the induced polarization in the $^2$H($\gamma,\vec n$)$^1$H reaction are needed in order to establish unequivocally whether there is a discrepancy between theory and experiment.