Quark-diquark description for mesons and baryons

por Atsushi Hosaka (RCNP Osaka University)

viernes 7 mar. 2003 12:00 → 13:00 Europe/Madrid

Sala Seminarios IFIC (Edf. Institutos de Investigación)

Nucleon structure and the origin and nature of the nuclear force are investigated in the context of a QCD-based effective field theory and the path-integral method of hadronization. We start from a microscopic model of quarks and diquarks where the gluons have been integrated out. In particular, we use the chiral Nambu-Jona-Lasinio model to describe quark dynamics and assume that the nucleon can be conceived as a quark-diquark relativistic bound state. The hadronization method is then used to rewrite the problem in terms of the physical meson and nucleon degrees of freedom. Next, by employing a loop and derivative expansion of the resulting quark/diquark determinants, we arrive at an effective chiral meson-nucleon Lagrangian. Nucleon properties such as mass, coupling constants, electromagnetic radii, anomalous magnetic moments, and form factors are derived using a theory of at most two free parameters.