Add vSMEFT to FeynRules/Models

FeynRules · BFuks · Nov 17, 2025 · Nov 15, 2025 · Nov 15, 2025 · Nov 15, 2025
commit cf53fcd4e21f6ed3123643246c3172b83ed25782
diff --git a/vSMEFT/LICENSE b/vSMEFT/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Arsenii Titov
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vSMEFT/README.md b/vSMEFT/README.md
@@ -0,0 +1,23 @@
+# FeynRules and UFO model files for <span>$\nu$</span>SMEFT
+
+The <span>$\nu$</span>SMEFT (also known as NSMEFT, SMNEFT, <span>$N_R$</span>SMEFT) is the effective field theory (EFT) of the Standard Model (SM) extended with right-handed (RH) neutrinos, $N_R$. 
+
+The FeynRules file `vSMEFT_Higgs-N.fr` extends the default [SM](https://feynrules.irmp.ucl.ac.be/wiki/StandardModel) model file and the [HeavyN](https://feynrules.irmp.ucl.ac.be/wiki/HeavyN) model file with **dimension-5 and dimension-6 Higgs-<span>$N_R$</span> interactions**. 
+In `SM_v_Majorana.fr` neutrinos are set to be Majorana (SelfConjugate -> True). This is the only difference with respect to the default SM model file `SM.fr` supplied with FeynRules.
+
+The Mathematica notebook `vSMEFT_Higgs-N_UFO.nb` loads and merges the FeynRules models `SM_v_Majorana.fr` and `vSMEFT_Higgs-N.fr`, performs a number of sanity checks, computes Feynman rules and generates the corresponding UFO model `vSMEFT_Higgs-N_UFO` (also available as a zip file `vSMEFT_Higgs-N_UFO.zip`). The latter can be used to perform simulations with MadGraph5_aMC@NLO.
+
+The present model files are largely based on those originally developed in Ref. [1](#ref2019). 
+Their description is provided in Ref. [2](#ref2025). 
+If you use the model files, please cite these references.
+
+
+## References
+
+1. <a id="ref2019"></a> J. M. Butterworth, M. Chala, C. Englert, M. Spannowsky and A. Titov,
+*Higgs phenomenology as a probe of sterile neutrinos*,
+[Phys. Rev. D **100** (2019) 115019](https://doi.org/10.1103/PhysRevD.100.115019) [[arXiv:1909.04665](https://arxiv.org/abs/1909.04665)].
+
+2. <a id="ref2025"></a> A. Titov, 
+*FeynRules and UFO model files for* <span>$\nu$</span>*SMEFT: Higgs-*<span>$N_R$</span> *operators of dimensions five and six*, 
+[arXiv:2511.XXXXX](https://arxiv.org/abs/2511.XXXXX).