Probing for N*s with Linearly Polarized Photons in Hall B of JLab

Idaho State University, Pocatello ID

Investigators

Abstract

The probe afforded by a beam of linearly-polarized photons allows one to gain access to several observables in photonucleon reactions, which otherwise would not be measureable. This polarization axis of the photon beam breaks the azimuthal symmetry of the reaction, thereby introducing an azimuthal dependence in the differential cross section. This additional information on the angular dependence opens the door to the measurement of a host of observables which are accessible only with a beam of linearly-polarized photons; consequently it provides important constraints on the nature of the photon-nucleon reaction. Such polarization observables are necessary for extracting the spin/parity of the broadly overlapping baryon resonances. Two PhD students at Idaho State University will analyze the g8b data set from Hall B of JLab. Their thesis topics will primarily focus on the search for baryon resonances (N*s) that decay though either the rho meson or hyperon channel, respectively. The PI has been very active in coordinating research efforts with nuclear physicists in Latin America. Over the past six years, he has been awarded five NSF grants, which serve to promote dialog among faculty members and students of North American and South American institutions. Through these efforts, he seeks to strengthen existing links and forge new ones within the broad scope of the international nuclear physics community. Such academic relationships, moreover, will further serve to strengthen the scientific research program between our respective continents. The PI expects to use this NSF award as a platform towards attracting additional grant money for these broader impact activities.