SARAH 4: A tool for (not only SUSY) model builders

TL;DR

<3-5 sentence high-level summary>: SARAH 4 addresses the challenge of extending automated model-building tools to non-supersymmetric (non-SUSY) theories, delivering a comprehensive framework for defining models, computing vertices, mass matrices, tadpoles, and self-energies, and deriving general $2$-loop RGEs validated against PyR@TE. The approach unifies model definitions with automatic Lagrangian generation, broadens Lie-group handling via Susyno, and enables outputs compatible with MC tools (FeynArts, CalcHep, WHIZARD, UFO) as well as SPheno-based spectrum generation and Vevacious vacuum checks. Key contributions include support for global symmetries, non-fundamental representations, and a fully automated workflow from model definition to phenomenological analysis, including numerical RGE running in Mathematica. The practical impact is a streamlined, end-to-end pipeline for exploring BSM scenarios beyond SUSY, with direct applicability to collider and precision-observable studies.

Abstract

We present the new version of the Mathematica package SARAH which provides the same features for a non-supersymmetric model as previous versions for supersymmetric models. This includes an easy and straightforward definition of the model, the calculation of all vertices, mass matrices, tadpole equations, and self-energies. Also the two-loop renormalization group equations for a general gauge theory are now included and have been validated with the independent Python code PyR@te. Model files for FeynArts, CalcHep/CompHep, WHIZARD and in the UFO format can be written, and source code for SPheno for the calculation of the mass spectrum, a set of precision observables, and the decay widths and branching ratios of all states can be generated. Furthermore, the new version includes routines to output model files for Vevacious for both, supersymmetric and non-supersymmetric, models. Global symmetries are also supported with this version and by linking Susyno the handling of Lie groups has been improved and extended.