SmeftFR v3 -- Feynman rules generator for the Standard Model Effective Field Theory

TL;DR

SmeftFR v3 is a Mathematica package that automates the generation of Feynman rules for the Standard Model Effective Field Theory, including operators up to dimension-8, facilitating advanced particle physics calculations.

Contribution

This version introduces the ability to compute SMEFT interactions up to dimension-8, including quadratic dimension-6 terms, with flexible gauge choices and export options.

Findings

Supports complete gauge invariant operators up to dimension-8.

Generates Feynman rules directly in the physical basis.

Includes a Latex generator for human-readable output.

Abstract

We present version 3 of SmeftFR, a Mathematica package designed to generate the Feynman rules for the Standard Model Effective Field Theory (SMEFT) including the complete set of gauge invariant operators up to dimension-6 and the complete set of bosonic operators of dimension-8. Feynman rules are generated with the use of FeynRules package, directly in the physical (mass eigenstates) basis for all fields. The complete set of interaction vertices can be derived, including all or any chosen subset of SMEFT operators. As an option, the user can also choose preferred gauge fixing, generating Feynman rules in unitary or $R_\xi$-gauges. The novel feature in version-3 of SmeftFR is its ability to calculate SMEFT interactions consistently up to dimension-8 in EFT expansion (including quadratic dimension-6 terms) and express the vertices directly in terms of user-defined set of input-parameters. The derived Lagrangian in the mass basis can be exported in various formats supported by FeynRules, such as UFO, FeynArts etc. Initialisation of numerical values of Wilson coefficients of higher dimension operators is interfaced to WCxf format. The package also includes a dedicated Latex generator allowing to print the result in clear human-readable form. The SmeftFR v3 is publicly available at www.fuw.edu.pl/smeft.