Dynamics, Symmetries and Hadron Properties.pdfVIP

11th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon September10-14, 2007 IKP, Forschungzentrum Jülich, Germany Dynamics, Symmetries and Hadron Properties I.C. Clo¨et,∗ A. Krassnigg † and C.D. Roberts ∗ ∗ Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, United States of America 7 † Institut f¨ur Physik, Karl-Franzens-Universit¨at Graz, 0 A-8010 Graz, Austria 0 2 t c Abstract O We provide a snapshot of Dyson-Schwinger equation applications to the the- 0 3 ory and phenomenology of hadrons. Exact results for pseudoscalar mesons ] are highlighted, with details relating to the UA (1) problem. Calculated h masses of the lightest J = 0, 1 states are discussed. We recapitulate upon t l- studies of nucleon properties and give a perspective on the contribution of c quark orbital angular momentum to the spin of a nucleon at rest. u n [ 1 Introduction 2 v 6 Numerous salient features exhibited by the physics of mesons and nucleons 4 7 arise nonperturbatively in QCD. Two phenomena strike one immediately: 5 confinement and dynamical chiral symmetry breaking (DCSB). DCSB is the . 0 better understood of these emergent phenomena; e.g., it explains the origin 1 of constituent-quark masses and underlies the success of chiral effective field 7 0 theory. Confinement, on the other hand, remains only an empirical fact; : v viz., colored objects have not hitherto been observed in isolation. A fact too i often ignored is that the potential between infinitely heavy quarks measured X