Meson Photo-Couplings From Lattice Quantum Chromodynamics

We explore the calculation of three-point functions featuring a vector current insertion in lattice Quantum Chromodynamics. These three-point functions, in general, contain information about many radiative transition matrix elements simultaneously. We develop and implement the technology necessary to isolate a single matrix element via the use of optimized operators, operators designed to interpolate a single meson eigenstate, which are constructed as variationally optimized linear combination of meson interpolating fields within a large basis. In order to frame the results we also explore some well known phenomenology arising within the context of the constituent quark model before transitioning to a lattice calculation of the spectrum of isovector mesons in a version of QCD featuring three flavors of quarks all tuned to approximately the physical strange quark mass. We then proceed to calculate radiative transition matrix elements for the lightest few isovector pseudoscalar and vector particles. The dependence of these form factors and transitions on the photon virtuality is extracted and some model intuitions are explored