Baryon chiral perturbation theory: one loop and beyond
Matthias R. Schindler
The George Washington University
For energies below 1 GeV, perturbative calculations in the strong coupling of QCD are
not meaningful. One of the theoretical tools to explore this energy region is the use
of an effective field theory, chiral perturbation theory (ChPT). After giving an
introduction to the underlying ideas of ChPT I will focus on the one-nucleon sector.
With the development of new renormalization schemes the evaluation of contributions
beyond one-loop order has become possible in a manifestly Lorentz-invariant
formulation. I will describe two different approaches to higher-order calculations:
the inclusion of additional degrees of freedom and the explicit calculation of
two-loop diagrams. Results for the nucleon form factors and the nucleon mass will be
presented. I will also discuss the connection to lattice QCD.