GravitinoPack and decays of supersymmetric metastable particles

Abstract We present the package GravitinoPack that calculates the two- and three-body decays of unstable supersymmetric particles involving the gravitino in the final or initial state. In a previous paper, we already showed results for the gravitino decaying into two and three particles. In this paper, we incorporate the processes where an unstable neutralino, stau or stop decays into a gravitino and Standard Model particles. This is the case in gravitino dark matter supersymmetric models, where the gravitino is the lightest SUSY particle. We give instructions for the installation and the use of the package. In the numerical analysis, we discuss various MSSM scenarios. We show that the calculation of all the decay channels and the three-body decay branching ratios is essential for the accurate application of cosmological bounds on these models. Program summary Program title: GravitinoPack Catalogue identifier: AEZL_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEZL_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 97708 No. of bytes in distributed program, including test data, etc.: 1217167 Distribution format: tar.gz Programming language: Fortran 77 and C for the MathLink. Computer: Workstation, PC, Mac. Operating system: Linux, Mac OSX. Classification: 11.1. Nature of problem: If Supersymmetry (SUSY) is realized in nature, each Standard Model (SM) particle is accompanied by its superpartner. The gravitino, the spin 3/2 superpartner of the graviton, belongs to the spectrum of the most important supersymmetric models. The gravitino can be the Lightest Supersymmetric Particle (LSP), in the so-called gravitino Dark Matter (DM) models. Thus, the Next to the Lightest Supersymmetric Particle (NLSP) is long-lived, since it decays gravitationally to the LSP (gravitino) and SM particles. Such decays produce electromagnetic energy and hadrons which can affect the primordial Big-Bang Nucleosynthesis (BBN) predictions for the abundance of the light nuclei. Similarly, when the gravitino is not the LSP it decays into the LSP which can be another SUSY particle, like the neutralino, and SM particles. GravitinoPack provides important results on all these decays, making the application of the BBN data more accurate. Solution method: GravitinoPack is a package for the evaluation of processes with gravitino interaction. The version GravitinoPack1.0 includes all two-body decays of the gravitino and all three-body decays of the gravitino to a neutralino and a pair of two particles. In the case that the gravitino is the LSP all two- and three-body decays of the lightest neutralino, the light stop or stau NLSP are included. GravitinoPack works at Fortran77 level and has a Mathematica interface. Unusual features: MathLink works properly only up to version Mathematica 9. There is still a conflict between Mathematica 10 and the used integration routine CUBA. Running time: All two-body decay widths are calculated in a time far below one second. The three-body decay calculations can be fast, especially the stop and stau decays, or slow with times up to a few minutes, especially when the phase space becomes large and no approximation is chosen.