Contributions of vector meson photoproduction to the   Gerasimov-Drell-Hearn sum rule
  An improved version of a recently developed quark model approach to vector meson photoproduction is applied to the investigation of contributions of vector meson photoproduction to the Gerasimov-Drell-Hearn (GDH) sum rule. We find that the sum rule converges at a few GeV's. Contributions to the proton channel are found to be small while to the neutron are relatively large. 
Q. Zhao, J.S. Al-Khalili, and C. Bennhold