FeynMG: A FeynRules extension for scalar-tensor theories of gravity

Sevillano Muñoz, Sergio; Copeland, Edmund J.; Millington, Peter; Spannowsky, Michael

Abstract

The ability to represent perturbative expansions of interacting quantum field theories in terms of simple diagrammatic rules has revolutionized calculations in particle physics (and elsewhere). Moreover, these rules are readily automated, a process that has catalyzed the rise of symbolic algebra packages. However, in the case of extended theories of gravity, such as scalar-tensor theories, it is necessary to precondition the Lagrangian to apply this automation or, at the very least, to take advantage of existing software pipelines. We present a Mathematica code FeynMG, which works in conjunction with the well-known package FeynRules, to do just that: FeynMG takes as inputs the FeynRules model file for a non-gravitational theory and a user-supplied gravitational Lagrangian. FeynMG provides functionality that inserts the minimal gravitational couplings of the degrees of freedom specified in the model file, determines the couplings of the additional tensor and scalar degrees of freedom (the metric and the scalar field from the gravitational sector), and preconditions the resulting Lagrangian so that it can be passed to FeynRules, either directly or by outputting an updated FeynRules model file. The Feynman rules can then be determined and output through FeynRules, using existing universal output formats and interfaces to other analysis packages.

Citation

Sevillano Muñoz, S., Copeland, E. J., Millington, P., & Spannowsky, M. (2024). FeynMG: A FeynRules extension for scalar-tensor theories of gravity. Computer Physics Communications, 296, Article 109035. https://doi.org/10.1016/j.cpc.2023.109035

• Journal Article Type: Article
• Acceptance Date: Nov 27, 2023
• Online Publication Date: Dec 6, 2023
• Publication Date: 2024-03
• Deposit Date: Jan 11, 2024
• Publicly Available Date: Jan 11, 2024
• Journal: Computer Physics Communications
• Print ISSN: 0010-4655
• Electronic ISSN: 1879-2944
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 296
• Article Number: 109035
• DOI: https://doi.org/10.1016/j.cpc.2023.109035
• Public URL: https://durham-repository.worktribe.com/output/2119285