Phenomenological Transition Amplitudes: Consequences for Pion and Eta Photoproduction in 1P-SHELL Nuclei.

Recent theoretical calculations for pion photoproduction for transitions in 1p-shell nuclei often rely on nuclear transition density matrix elements extracted from low energy electromagnetic and weak observables. I determine "windows of reliability" of nuclear structure input these calculations by extracting the one-body densities as a function of momentum transfer from electromagnetic and weak observables. At high momentum transfer (q > 3fm ^{-1}, for example), harmonic oscillator single-particle wavefunctions decay too rapidly. Radial wavefunctions obtained by using the Hartree-Fock method or generated from the Wood-Saxon well can improve the fit to the electroweak observables at momentum transfers where the harmonic oscillator wavefunctions become inadequate. I examined possible meson-exchange current effects, from which pion photoproduction appears to be immune. I confront pion photoproduction measurements to assess the differences between the theoretical predictions of my amplitudes and the amplitudes of other works. I demonstrate that nuclear photoproduction with polarized photons can be particularly sensitive to model ingredients, such as nuclear structure and the impulse amplitude. I exploit this sensitivity using the photon asymmetry, which is a measure of the nuclear response to the different photon polarizations. Finally, I study eta photoproduction to investigate the roles of the S_{11}(1535) resonance, vector mesons, and the s-and u- channel nucleon Born terms. The pure M1 1p-shell transitions studied in this thesis are: ^6Li_{rm g.s.} to ^6 Li*(3.56MeV), ^{12}C _{rm g.s.} to ^{12}C*(15.11MeV), and ^{14}N_ {rm g.s.} to ^{14}N*(2.313MeV). These transitions are of interest to the experimental studies at various photon factories around the world.