First measurements of spin-dependent double-differential cross sections and the Gerasimov-Drell-Hearn integrand from \vec{{^3}}He(\vec{\gamma},n)pp at incident photon energies of 12.8 and 14.7 MeV
G. Laskaris et al.
Accepted
The first measurement of the three-body photodisintegration of longitudinally-polarized $^3$He with a circularly-polarized $\gamma$-ray beam was carried out at the High Intensity $\gamma$-ray Source (HI$\gamma$S) facility located at Triangle Universities Nuclear Laboratory (TUNL). The spin-dependent double-differential cross sections and the contributions from the three-body photodisintegration to the $^3$He GDH integrand are presented and compared with state-of-the-art three-body calculations at the incident photon energies of 12.8 and 14.7 MeV. The data reveal the importance of including the Coulomb interaction between protons in three-body calculations.