Disrupting the one-loop renormalization group invariant M/α in supersymmetry

It is well known that in low energy supersymmetry the ratio of the gaugino mass to the gauge coupling squared, M/alpha, is renormalization group invariant to one loop. We present a systematic analysis of the corrections to this ratio, including standard two-loop corrections from gauge and Yukawa couplings, corrections due to an additional U(1)' gaugino, threshold corrections, superoblique corrections, corrections due to extra matter, GUT and Planck scale corrections, and "corrections" from messenger sectors with supersymmetry breaking communicated via gauge mediation. We show that many of these effects induce corrections at the level of a few to tens of percent, but some could give much larger corrections, drastically disrupting the renormalization group extrapolation of the ratio to higher scales. Our analysis is essentially model-independent, and therefore can be used to determine the ambiguities in extrapolating the ratio in any given model between the weak scale and higher scales. (C) 1998 Elsevier Science B.V.