FlexibleSUSY extended to automatically compute physical quantities in any beyond the standard model theory: Charged lepton flavor violation processes, Higgs decays, and user-defined observables

Abstract

FlexibleSUSY is a framework for the automated computation of physical quantities (observables) in models beyond the Standard Model (BSM). This paper describes an extension of FlexibleSUSY which allows to define and add new observables that can be enabled and computed in applicable user-defined BSM models. The extension has already been used to include Charged Lepton Flavor Violation (CLFV) observables, but further observables can now be added straightforwardly. The paper is split into two parts. The first part is non-technical and describes from the user's perspective how to enable the calculation of predefined observables, in particular CLFV observables. The second part of the paper explains how to define new observables such that their automatic computation in any applicable BSM model becomes possible. A key ingredient is the new NPointFunctions extension which allows to use tree-level and loop calculations in the model-independent setup of observables. Three examples of increasing complexity are fully worked out. This illustrates the features and provides code snippets that may be used as a starting point for implementation of further observables.

Program summary

Program title: NPointFunctions

CPC Library link to program files: https://doi.org/10.17632/kf7m8gn8vp.2

Developer's repository link: https://github.com/FlexibleSUSY/FlexibleSUSY

Licensing provisions: GPLv3

Programming language: C++, Wolfram Language, Fortran, Bourne shell

Journal reference of previous version:: Comput. Phys. Commun. 230 (2018) 145–217; PoS CompTools2021 (2022) 036

Does the new version supersede the previous version?: Yes

Reasons for the new version: Program extension including new observables and file structures

Nature of problem: Determining observables for an arbitrary extension of the Standard Model supported by FlexibleSUSY, input by the user.

Solution method: Generation of the code from automated algebraic manipulations. Automatic filling and compiling of predefined template files.

Additional comments including restrictions and unusual features: Vertices with a direct product of Lorentz and color structures are supported. Settings of the advanced NPointFunctions mode rely on explicit specification of topologies.