An effective action for the supersymmetric CPsup(n-1) model

We explicitly construct the low-energy effective action for the 'composite' fields in the supersymmetric CPsup(n-1) model. It contains two chiral superfields S and anti S. We find that the anomaly structure is exactly reproduced by the term S log S first proposed by Veneziano and Yankielowicz. In addition, the effective action contains additional terms involving derivatives of the superfields S and anti S. These terms are invariant under the anomalous transformations and, in general, cannot be neglected in the low-energy limit. (orig.)