Comparison of SUSY mass spectrum calculations.pdf

a r X i v : h e p - p h / 0 2 0 7 3 1 4 v 1 2 5 J u l 2 0 0 2 Comparison of SUSY mass spectrum calculations B. Allanach, S. Kraml,1 W. Porod Abstract We provide a comparison of the results of four SUSY mass spectrum calculations in mSUGRA: Isajet, SuSpect, SoftSusy, and SPheno. In particular, we focus on the high tanβ and focus point regions, where the differences in the results are known to be large. Contribution to SUSY02, 10th International Conference on Supersymmetry and Unification of Fundamental Interactions, 17–23 June 2002, DESY Hamburg, Germany. 1 Introduction Many SUSY studies rely on computer codes that calculate the mass spectrum of the minimal supersymmetric standard model (MSSM), the couplings, branching ratios, etc., from given sets of model parameters. For the LHC, for instance, many simulations are done for particular benchmark scenarios or by mapping the (m0, m1/2) parameter plane. For such studies it is certainly important wheather a particular decay channel is open or not and what branching ratio it has. Also, theoretically or experimentally excluded regions depend on the details of the spectrum. Studies for an e+e? Linear Collider deal, in addition, with high precision measurements of (s)particle properties, with the determina- tion of the underlying SUSY breaking parameters, their extrapolation to the GUT scale, model destinction, etc. Experimental accuracies of the per-cent or even per-mille level are expected. It is thus clear that we need theoretical predictions of a precision comparable to the experimental accuracy. However, it has been noticed [1, 2] that different programs can give quite different results for the same set of input parameters. In this article, we compare the mass spectrum calculations of four public codes: Isajet 7.63 [3], SuSpect 2.005 [4], SoftSusy 1.4 [5], and SPheno 1.0 [6], in the minimal su- pergravity (mSUGRA) framework. We discuss the renormalization group (RG) running and the implementation of radiative corre