### Diana Nicmorus

University of Graz, Austria
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Baryon-photon interaction in a Dyson-Schwinger equation approach

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 and delta resonance masses and their
electromagnetic 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
baryon-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 and delta 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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