Supercurrent and local coupling in the Wess-Zumino model

We study the Wess-Zumino model with the coupling extended to a chiral superfield. In order to incorporate the renormalization effects a further external real field has to be introduced. It is then possible to derive a Callan-Symanzik equation and to prove renormalizability. By constructing the supercurrent in this context the whole machinery for describing the superconformal symmetries becomes available. The presence of the external fields allows also to define multiple insertions of all relevant composite operators. Interesting relations to the curved superspace treatment show up. (orig.)