Measurement of the Neutron Polarization fromD(p, n)2p

The polarization of breakup neutrons from the reaction $\mathrm{D}(p, n)2p$ has been measured at $E_p=21.5\mathrm{}$ MeV as a function of neutron energy with accuracy of approximately ± 0.01. The high-energy neutrons ($E_n>14\mathrm{}$ MeV) show a small but significant positive polarization ($P_n\sim 0.015$), in disagreement with the prediction ($P_n=0\mathrm{}$) of the Amado model and also in disagreement with expectations if the dominant process were simple quasifree $p-n$ scattering.