No Arabic abstract
A pedagogical overview of the formulation of the Fat Link Irrelevant Clover (FLIC) fermion action and its associated phenomenology is described. The scaling analysis indicates FLIC fermions provide a new form of nonperturbative O(a) improvement where near-continuum results are obtained at finite lattice spacing. Spin-1/2 and spin-3/2, even and odd parity baryon resonances are investigated in quenched QCD, where the nature of the Roper resonance and Lambda(1405) are of particular interest. FLIC fermions allow efficient access to the light quark-mass regime, where evidence of chiral nonanalytic behavior in the Delta-baryon mass is observed.
We provide a snapshot of Dyson-Schwinger equation applications to the theory and phenomenology of hadrons. Exact results for pseudoscalar mesons are highlighted, with details relating to the U_A(1) problem. Calculated masses of the lightest J=0,1 states are discussed. We recapitulate upon studies of nucleon properties and give a perspective on the contribution of quark orbital angular momentum to the spin of a nucleon at rest.
We summarise applications of Dyson-Schwinger equations to the theory and phenomenology of hadrons. Some exact results for pseudoscalar mesons are highlighted with details relating to the U_A(1) problem. We describe inferences from the gap equation relating to the radius of convergence for expansions of observables in the current-quark mass. We recapitulate upon studies of nucleon electromagnetic form factors, providing a comparison of the ln-weighted ratios of Pauli and Dirac form factors for the neutron and proton.
Lattice calculations for hadrons are now entering the domain of resonances and scattering, necessitating a better understanding of the observed discrete energy spectrum. This is a reviewing survey about recent lattice QCD results, with some emphasis on spectrum and scattering.
We summarize our current understanding of the connection between the QCD phase line and the chemical freeze-out curve as deduced from thermal analyses of yields of particles produced in central collisions between relativistic nuclei.
Hadron production in relativistic nuclear collisions is well described in the framework of the Statistical Hadronization Model (SHM). We investigate the influence on SHM predictions of hadron mass spectra for light-flavor baryons and mesons modified by the addition of about 500 new states as predicted by lattice QCD and a relativistic quark model. The deterioration of the resulting thermodynamic fit quality obtained for PbPb collision data at sqrt(s_nn) = 2.76 TeV suggests that the additional states are not suited to be naively used since also interactions among the states as well as non-resonant contributions need to be considered in the SHM approach. Incorporating these effects via the pion nucleon interaction determined from measured phase shifts leads again to excellent reproduction of the experimental data. This is a strong indication that at least the additional nucleon excited states cannot be understood and used as independent resonances.