Gerasimov-Drell-Hearn sum rule for the deuteron

This sum rule is based on very general principals: causality, unitarity, gauge and Lorentz invariance.  Inconsistencies with the sum rule would indicate a breakdown in some generally accepted physics. Comparisons with measurements on neutrons and protons indicate that there should be a very large and negative contribution to the GDH sum for the Deuteron at low energies. Therefore lower energy measurements using the High Intensity Gamma-Ray Source (HIGS) facility, will provide a valuable complement to high energy measurement made elsewhere. Circularly polarized gamma rays from the HIGS facility will impinge on a polarized deuterium target. The neutrons from the photodisintegration of the deuterium will be detected by the segmented liquid-scintillator array know as Blowfish.