On the treatment of threshold effects in SUSY spectrum computations

We take a critical view of the treatment of threshold effects in SUSY spectrum computations from high-scale input. We discuss the two principal methods of (a) renormalization at a common SUSY scale versus (b) integrating out sparticles at their own mass scales. We point out problems in the implementations in public spectrum codes, together with suggestions for improvements. In concrete examples, we compare results of Isajet7.72 and Spheno2.2.3, and present the improvements done in Isajet7.73. We also comment on theoretical uncertainties. Last but not least, we outline how a consistent multiscale approach may be achieved.