Hadronic decays

Hadronic decays and transitions are a key ingredient of hadronic physics. I discuss how hadronic decays can be explored in lattice gauge theory and review studies undertaken. I also discuss the impact of decays on masses and how lattice studies can explore the nature of a hadronic state: namely whether it is a molecular or quark-antiquark state. A brief discussion of lattice exploration of pentaquark states is presented.Comment: 14 pages, plenary talk at Lattice 2005, Dublin, July 25-3

The eta and eta' mesons from lattice QCD

Lattice QCD allows a first-principles study of QCD with the freedom to vary the number and masses of the quarks. I present results on the flavour singlet correlations (this illuminates OZI violating effects) for mesons. Concentrating on the pseudoscalar mesons, the flavour singlet mass splitting ($\eta$, $\eta'$ mass splitting) appears naturally. I also present results on an investigation of decay constants for the $\eta$ and $\eta'$ ($f_{\eta}$) and discuss which quantities may be accessible in future lattice studies. The Witten-Veneziano approach can also be explored by determining the quenched topological susceptibility on a lattice.Comment: 13 pages, LATEX, 3 ps figures, Proc. WORKSHOP ON ETA PHYSICS, Uppsala, October 22-27, 200

Lattice sum rules for the colour fields

We analyse the sum rules describing the action and energy in the colour fields around glueballs, torelons and static potentials.Comment: 9 pages LATEX, (typos corrected, to appear in Phys Rev D

The Mass Spectrum of a Static Adjoint Particle

The bound states of fermions in the adjoint representation are of interest in supersymmetric models. We investigate the energy spectrum of the simplest -- the gluino-gluon bound states -- on several lattices in the quenched approximation. We use a static approximation for the gluino propagator. We find continuum limits of the splitting between the few lowest states, with the energy difference between the two lowest states of $354 \pm 9$ MeV.Comment: 3 pages, Latex, to appear Lattice 97 proceding