A Program in Medium-Energy Nuclear Physics

Abstract

We report here on the final stages of the Berman grant. The study of the spectrum and properties of the excited states of the nucleon (the N* states) is one of the highest-priority goals of nuclear physics and one of the major programs of Jefferson Lab, especially in Hall B. We have most recently focused our attention on exclusive studies (in both spin and strangeness) of the neutron in the deuteron. Our g13 experiment, “Production of Kaons from the Deuteron with Polarized Photons” [Nadel-Turonski (2006)], was carried out between October 2006 and June 2007. This experiment was done using both linearly and circularly polarized photons, mainly to try to unscramble the multitude of wide and overlapping N* states and to measure their properties by studying in fine detail their decays into strange-particle reaction channels. To this end, one of our students, Edwin Munevar, has analyzed the γn→K + Σ - reaction channel for his Ph.D. topic. The strangeness-production channels constitute the subject of the original GW group’s g13 proposal. But the g13 data set, by virtue of its statistics, polarization, and kinematic coverage, is ideally suited for many other reaction channels as well. Among these is the azimuthal angular asymmetry for deuteron photodisintegration, which was analyzed by another of our students, Nicholas Zachariou, for his Ph.D. topic, with help from Nickolay Ivanov (from the Yerevan Physics Institute in Armenia). This study required a deuterium target and a linearly polarized photon beam.