ar X iv : h ep - p h / 04 02 14 5 v 2 2 1 Fe b 20 04 Automatic one - loop calculation of MSSM processes with GRACE

Supersymmetry (SUSY) between bosons and fermions at the unification-energy scale is one of the most promising hypothesis, which is expecteted to resolve the remaining problems in the standard model. In particular, the minimal supersymmetric extension of the the standard model (MSSM) [1] has been extensively studied in the last decade due to the simplicity. For more than ten years, we have been developing the system of the automatic computation of the high energy physics processes. The system for the computation of the standard model(SM), GRACE, has been published in [2]. For including the interactions of SUSY particles in the GRACE system, we have made several modifications and the expansion of the system [3,4]. As the first outcome from GRACE/SUSY, we have published a package of event-generator, SUSY23, which contains 23 specific SUSY processes for ee → 2-body and 3-body [5]. At this stage, the model definition files are based on the Hikasa’s Manual [6]. Recently, we have constructed the complete lagrangian of MSSM [7] using the European convention: namely, the positive chargino is called a particle and the ranges of μ and tanβ are defined as 0 ≤ tanβ ≤ 1 and −∞ ≤ μ ≤ +∞ . Thus we have published the new version of GRACE/SUSY (GRACE v2.2.0) [8], which is available from http://minami-home.kek.jp/ . In the world, there exist several groups independently developing the systems of the automatic computation in SM with different methods [9,10,11,12], and also developing the system of the automatic computation in MSSM [13]. In this paper, we present the latest development of the GRACE/SUSY system including the one-loop calculations in MSSM.