First Study of Three-body Photo-disintegration of $^3$He $\overrightarrow{^3He}(\vec{\gamma},n)pp$ with Double Polarizations*

The study of the three-nucleon system has long been of fundamental importance to nuclear physics. We report on a first study of three-body photo-disintegration of polarized $^3$He with a circularly polarized $\gamma$-ray beam at an incident energy of 11.4 MeV. This experiment was carried out at the High Intensity $\gamma$-Ray Source (HI$\gamma$S) facility located at the Duke University Free Electron Laboratory. A high-pressure polarized $^3$He target based on spin-exchange optical pumping of hybrid alkali was used in the experiment. Both differential cross sections and asymmetries were extracted from the experiment. The results are compared to the three-body calculations using both CD Bonn and AV18 potentials and are in agreement within experimental uncertainties.