Radiative capture of polarized neutrons by polarized protons at Tn=183 MeV.

Abstract

In order to provide a quantitative test of theoretical calculations incorporating meson-exchange currents and intermediate $\ensuremath{\Delta}$ resonances, we measure the normal-component spin correlation coefficient ${C}_{\mathrm{NN}}$, the differential cross section $\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}}$, and the neutron and proton analyzing powers ${A}_{n}$ and ${A}_{p}$, each as a function of angle, for $\stackrel{\ensuremath{\rightarrow}}{n}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}d\ensuremath{\gamma}$ at ${T}_{n}=183$ MeV. Our $\stackrel{\ensuremath{\rightarrow}}{n}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\rightarrow}d\ensuremath{\gamma}$ results, combined with the previous cross section and photon asymmetry data collected in the past decade, place quite strong constraints on model calculations. Our data are in excellent agreement with theoretical predictions by Jaus and Woolcock that incorporate meson-exchange and isobar current effects and relativistic corrections, signifying great recent progress in our understanding of these effects in the nucleon-nucleon system.