SARAH 3.2: Dirac gauginos, UFO output, and more

SARAH is a Mathematica package optimized for the fast, efficient and precise study of supersymmetric models beyond the MSSM: a new model can be defined in a short form and all vertices are derived. This allows SARAH to create model files for FeynArts/FormCalc, CalcHep/CompHep and WHIZARD/O’Mega. The newest version of SARAH now provides the possibility to create model files in the UFO format which is supported by MadGraph 5, MadAnalysis 5, GoSam, and soon by Herwig++. Furthermore, SARAH also calculates the mass matrices, RGEs and 1-loop corrections to the mass spectrum. This information is used to write source code for SPheno in order to create a precision spectrum generator for the given model. This spectrum-generator–generator functionality as well as the output of WHIZARD and CalcHep model files has seen further improvement in this version. Also models including Dirac gauginos are supported with the new version of SARAH, and additional checks for the consistency of the implementation of new models have been created.Program summaryProgram title:SARAHCatalogue identifier: AEIB_v2_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIB_v2_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 3 22 411No. of bytes in distributed program, including test data, etc.: 3 629 206Distribution format: tar.gzProgramming language: Mathematica.Computer: All for which Mathematica is available.Operating system: All for which Mathematica is available.Classification: 11.1, 11.6.Catalogue identifier of previous version: AEIB_v1_0Journal reference of previous version: Comput. Phys. Comm. 182 (2011) 808Does the new version supersede the previous version?: Yes, the new version includes all known features of the previous version but also provides the new features mentioned below.Nature of problem:To use Madgraph for new models it is necessary to provide the corresponding model files which include all information about the interactions of the model. However, the derivation of the vertices for a given model and putting those into model files which can be used with Madgraph is usually very time consuming.Dirac gauginos are not present in the minimal supersymmetric standard model (MSSM) or many extensions of it. Dirac mass terms for vector superfields lead to new structures in the supersymmetric (SUSY) Lagrangian (bilinear mass term between gaugino and matter fermion as well as new D-terms) and modify also the SUSY renormalization group equations (RGEs). The Dirac character of gauginos can change the collider phenomenology. In addition, they come with an extended Higgs sector for which a precise calculation of the 1-loop masses has not happened so far.Solution method:SARAH calculates the complete Lagrangian for a given model whose gauge sector can be any direct product of SU(N) gauge groups. The chiral superfields can transform as any, irreducible representation with respect to these gauge groups and it is possible to handle an arbitrary number of symmetry breakings or particle rotations. Also the gauge fixing is automatically added. Using this information, SARAH derives all vertices for a model. These vertices can be exported to model files in the UFO which is supported by Madgraph and other codes like GoSam, MadAnalysis or ALOHA.The user can also study models with Dirac gauginos. In that case SARAH includes all possible terms in the Lagrangian stemming from the new structures and can also calculate the RGEs. The entire impact of these terms is then taken into account in the output of SARAH to UFO, CalcHep, WHIZARD, FeynArts and SPheno.Reasons for new version:SARAH provides, with this version, the possibility of creating model files in the UFO format. The UFO format is supposed to become a standard format for model files which should be supported by many different tools in the future. Also models with Dirac gauginos were not supported in earlier versions.Summary of revisions:Support of models with Dirac gauginos. Output of model files in the UFO format, speed improvement in the output of WHIZARD model files, CalcHep output supports the internal diagonalization of mass matrices, output of control files for LHPC spectrum plotter, support of generalized PDG numbering scheme PDG.IX, improvement of the calculation of the decay widths and branching ratios with SPheno, the calculation of new low energy observables are added to the SPheno output, the handling of gauge fixing terms has been significantly simplified.Restrictions:SARAH can only derive the Lagrangian in an automatized way for N=1 SUSY models, but not for those with more SUSY generators. Furthermore, SARAH supports only renormalizable operators in the output of model files in the UFO format and also for CalcHep, FeynArts and WHIZARD. Also color sextets are not yet included in the model files for Monte Carlo tools. Dimension 5 operators are only supported in the calculation of the RGEs and mass matrices.Unusual features:SARAH does not need the Lagrangian of a model as input to calculate the vertices. The gauge structure, particle and content and superpotential as well as rotations stemming from gauge symmetry breaking are sufficient. All further information is derived by SARAH on its own. Therefore, the model files are very short and the implementation of new models is fast and easy. In addition, the implementation of a model can be checked for physical and formal consistency. In addition, SARAH can generate Fortran code for a full 1-loop analysis of the mass spectrum in the context for Dirac gauginos.Running time:Measured CPU time for the evaluation of the MSSM using a Lenovo Thinkpad X220 with i7 processor (2.53 GHz).Calculating the complete Lagrangian: 9 s.Calculating all vertices: 51 s.Output of the UFO model files: 49 s.