Supersymmetric mass spectra within two variants of the seesaw mechanism,
commonly known as type-II and type-III seesaw, are calculated using full 2-loop
RGEs and minimal Supergravity boundary conditions. The type-II seesaw is
realized using one pair of 15 and 15ˉ superfields, while the type-III is
realized using three copies of 24M superfields. Using published, estimated
errors on SUSY mass observables attainable at the LHC and in a combined LHC+ILC
analysis, we calculate expected errors for the parameters of the models, most
notably the seesaw scale. If SUSY particles are within the reach of the ILC,
pure mSugra can be distinguished from mSugra plus type-II or type-III seesaw
for nearly all relevant values of the seesaw scale. Even in the case when only
the much less accurate LHC measurements are used, we find that indications for
the seesaw can be found in favourable parts of the parameter space. Since our
conclusions crucially depend on the reliability of the theoretically forecasted
error bars, we discuss in some detail the accuracies which need to be achieved
for the most important LHC and ILC observables before an analysis, such as the
one presented here, can find any hints for type-II or type-III seesaw in SUSY
spectra.Comment: 31 pages, 49 figure