First Measurements Of Spin-Dependent Double-Differential Cross Sections And The Gerasimov-Drell-Hearn Integrand From (3)(H)Over-Right-Arrowe((Gamma)Over-Right-Arrow, N)Pp At Incident Photon Energies Of 12.8 And 14.7 Mev

The first measurement of the three-body photodisintegration of longitudinally polarized He-3 with a circularly polarized gamma-ray beam was carried out at the High Intensity gamma-ray Source facility located at Triangle Universities Nuclear Laboratory. The spin-dependent double-differential cross sections and the contributions from the three-body photodisintegration to the He-3 Gerasimov-Drell-Hearn 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.