FeynRules and UFO models for $\nu$SMEFT: operators of dimensions five and six

Abstract

We release FeynRules and UFO model files for the $\nu$SMEFT -- the effective field theory of the Standard Model extended with right-handed neutrinos, $N_R$. These model files include operators with $N_R$ up to dimension six. In particular, we provide a UFO implementation of four-fermion operators with Majorana $N$ compatible with MadGraph5_aMC@NLO. It relies on introducing auxiliary, non-propagating fields. All the model files are made publicly available on https://github.com/arsenii-titov/vSMEFT.

Comments: 31 pages, 4 figures, 5 tables; major update: added a FeynRules implementation of four-fermion operators involving Majorana $N$, based on non-propagating auxiliary fields and enabling the generation of UFO models compatible with MadGraph5_aMC@NLO; title and structure revised accordingly; model files available at https://github.com/arsenii-titov/vSMEFT