A Note on the Effective Soft SUSY-Breaking Lagrangian Below the GUT Scale

Abstract

I consider the superfield derivation of the effective theory of softly broken supersymmetry below the GUT scale. I point out the role of supergauge invariance in determining the form of the result, which is rather restricted in interesting classes of models. As an example I discuss sfermion mass splittings for matter embedded in a single GUT multiplet. Interesting differences arise between the cases of $SU(5)$, $SO(10)$ and $E_6$.