[Jlab-seminars] Theory Center Seminar

[Mary Fox]

Theory Center Seminar
Wed., March 24, 2010
3:00 p.m.
CEBAF Center, Room L104

A Dyson-Schwinger Equation Study of the Nucleon-Photon Vertex

Diana Nicmorus
Univ. Graz, Austria

I present a Dyson-Schwinger equation motivated study of the physics
that governs the nucleon. In particular I focus on the quark-core
contributions to the nucleon mass and form factors. The calculations
are performed within a Poincare-covariant Faddeev framework
describing the quark-core of the nucleon via a quark-diquark picture.
A consistent setup for the dressed-quark propagator, the quark-quark
and the quark-diquark interactions is used, where all the ingredients
are solutions of their respective Dyson-Schwinger or Bethe-Salpeter
equations and obtained in the rainbow-ladder truncation. In the
quark-diquark picture a nucleon-photon vertex that fulfills the
electromagnetic Ward-Takahashi identity is resolved by specifying
the quark-photon and diquark-photon vertices, and by using a
consistent ansatz for the seagull terms. I discuss the evolution of
the nucleon properties with the current quark mass, as well as the
role of the pion cloud in this approach. I also present a comparison
of the results to a collection of experimental and lattice data.




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