The Δ(1232) -resonance in chiral effective field theory

The problem of formulating the baryon chiral perturbation theory (BχPT) in the presence of a light resonance, such as the Δ ( 1232 ) the lightest nucleon resonance, is discussed. It is shown how to extend the power counting of BχPT to correctly account for the resonant contributions. Recent applications of the resulting chiral effective field theory to the description of pion production reactions in the Δ -resonance region are briefly reviewed.