Status report on the NSAC Subcommittee on Electromagnetic Interactions

The Subcommittee has formulated its view of the physics program to be pursued in the coming years together with an analysis of the facility parameters that will be required in order to execute the highest priority components of this program. The Subcommittee foresees the opening of a new frontier for the investigation of nuclear phenomena in the momentum transfer range q = 5 to 15 fm-1 and electron energy range up to 4 GeV. Because of the opportunities they offer for fundamental advances using electromagnetic probes, the Subcommittee assigned the highest scientific priority to investigation of hadron structure and two body interactions, three and four body systems, and fundamental symmetries. This is both because of their intrinsic scientific interest and because of the opportunity they offer to study the largely unexplored transition between nucleon-meson and the quark-gluon descriptions of nuclear systems. The Subcommittee strongly recommends the construction of a variable energy electron beam facility capable of operation at both high intensity and high duty factor, and able to achieve an electron energy of about 4 GeV, for the purpose of making coincidence measurements on nuclear targets at large excitation energy and momentum transfer