The Vector Meson Mass in Chiral Effective Field Theory

Abstract

A brief overview of Quantum Chromodynamics (QCD) as a non-Abelian gauge field theory, including symmetries and formalism of interest, will precede a focused discussion on the use of an Effective Field Theory (EFT) as a low energy perturbative expansion technique. Regularization schemes involved in Chiral Perturbation Theory (ḩi}PT) will be reviewed and compared with EFT. Lattices will be discussed as a useful procedure for studying large mass particles. An Effective Field Theory will be formulated, and the self energy of the h̊o} meson for a Finite-Range Regulated (FRR) theory will be calculated. This will be performed in both full QCD and the simpler quenched approximation (QQCD). Finite-volume artefacts, due to the finite box size on the lattice, will be quantified. Currently known lattice results will be used to calculate the h̊o} meson mass, and the possibility of unquenching will be explored. The aim of the research was to determine whether a stable unquenching procedure for the h̊o} meson could be discovered. The results from the original research indicate that there is no such procedure because the h̊o} mesons are unstable. Unless additional data involving lighter quark masses is available, an element of modelling is needed for successful unquenching.

Comments: First-class Honours thesis (Mathematical Physics), 2007