CONTROLLED SOFT BREAKING OF N=1 SQCD

We discuss the introduction of soft breaking terms into the exact solu tions of N = 1 SQCD using a spurion analysis. The spurion symmetries a re not sufficient to determine the behavior of models in which squark or gaugino masses alone are introduced. However, a controlled approxim ation is obtained in some cases if a supersymmetric mass is first intr oduced for the matter fields. We present low-energy solutions for two models with perturbing soft breaking terms, one with a gaugino mass an d one with squark mixing. These models have non-trivial theta angle de pendence and exhibit phase transitions at non-zero theta angle analogo us to those found in the chiral Lagrangian description of QCD. (C) 199 7 Elsevier Science B.V.