Version 9 (modified by YunJiang, 2 years ago) (diff)


Standard Model Effective Field Theory (SMEFT)


Ilaria Bravio, Yun Jiang and Micheal Trott

"ilaria.brivio@…", "yunjiagn@…", "michael.trott@…"

NBIA and Discovery Center, Niels Bohr Institute, University of Copenhagen

The model description

The SMEFT is constructed out of a series of SUC(3) × SUL(2) × UY(1) invariant (local and analytic) higher dimensional operators built out of the SM fields.

The main purpose of the SMEFTsim package is to provide a complete tool for the analysis of the tree level interference terms between the $L_{6}$ dependent amplitude and the SM amplitudes in a measured process.

The implementation of the entire parameter space of the SMEFT and the automatic inclusion of the shifts due to the choice of an input parameters set is a key feature.

In this spirit, the models are not meant to be employed for the extraction of accurate SM predictions and they are not equipped for NLO calculations in MadGraph5_aMC@NLO.

The SMEFTsim package consists of several model files for the tree-level analysis of the SMEFT at d = 6. It contains both model files for FeynRules [6] and pre-exported UFO files [5] to be interfaced e.g. with MadGraph5_aMC@NLO [83]. Two independent models sets are supplied, called “Models set A” and “Models set B”: each contains three different versions of the SMEFT: a fully flavour general SMEFT, a U(3)5 − SMEFT with non-SM complex phases and MFV − SMEFT.12 In addition, each case has

All the models are built upon the default SM implementation in FeynRules, from which they inherit the SM fields, parameters and Lagrangian definitions. The original file has been extended and modified to include the complete set of L(6) baryon number conserving operators of the Warsaw basis. The loop-induced effective couplings of SM Higgs to gg, γγ and Zγ have also been included. At this stage, the ghost Lagrangian has been left in its SM form.


  1. Bravio, Y. Jiang and M. Trott, The SMEFTsim package, theory and tools, arXiv:1709.XXXX

Model Set A

Model Set B

Main FeynRules file for the SMEFTsim model: 


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