Study of nuclear media effects in meson photoproduction

In addition to the current BGO-OD experimental program we propose to study nuclear media effects in photoproduction of mesons using a new experimental method based on measuring a recoil nucleon as a tagger of the selected partial channel. The principal goal is to learn how unstable mesons (πo, π+, π−, η, ρ, ω, etc.) interact with nuclear media. This approach continues previous GRAAL experiments to study nuclear excitation dynamics, including multifragmentation of nuclei by intermediate energy photons.

RELATIVISTIC DESCRIPTION OF QUASIFREE ETA PHOTOPRODUCTION

A relativistic plane wave formalism for quasifree eta meson photoproduction is presented. The sensitivity of the unpolarized differential cross section, the recoil nucleon polarization, and the photon asymmetry is investigated. The results indicate that the S11 resonance dominates the unpolarized differential cross section, but that its contribution to the spin observables are very small, for which the D13 resonance plays the primary role.