The EFT mass basis model

Authors

• Benjamin Fuks (IPHC Strasbourg / U. Strasbourg)
• Kentarou Mawatari (Vrije Universiteit Brussel)
  • Emails: benjamin.fuks @ iphc.cnrs.fr, kentarou.mawatari @ vub.ac.be

Description of the model

This is a model file based on the Standard Model (SM) effective-field-theory (EFT) Lagrangian in the mass basis. We adopt the notation of the Lagrangian in the Higgs basis proposal for LHC HXSWG and additionally consider all couplings external parameters that can be tuned according to the needs of the user. More information on the parameterization can be found on ​the HXSWG page. All the coefficients of the operators in the mass basis are hence implemented as external parameters in the FeynRules implementation (i.e. independent parameters), although a large fraction of them are dependent as soon as one considers a gauge-invariant set of independent operators in the SM EFT, as done e.g. in the Warsaw or SILH bases. The translation of the coefficients from those bases to the mass basis can be done by ​Rosetta, and an output parameter card from Rosetta can be used as an input card for FeynRules and for event generators (e.g. MadGraph5_aMC@NLO), with the mass-basis (MB) model file. See more details in

• ​1508.05895 : A. Falkowksi, B. Fuks, K. Mawatari, K. Mimasu, F. Riva, V. Sanz, "Rosetta: an operator basis translator for Standard Model effective field theory".

This is an extension of the Higgs characterisation model.

Model files

• MB.fr : The main model file.
• SM_MB.fr : This model requires the modified SM implementation of FeynRules.
• Massless.rst: restriction files tha can be possibly used.
• MB.nb : This is an example Mathematica notebook that loads the model, calculates the Feynman rules and extract the model files within the UFO format.
• mb_full.ufo.tgz : The model files in UFO format (for, e.g. MadGraph5_aMC@NLO).

Version updates

• 30.07.2015 - v1.1: modification of the handling of the flavor structure. Update to the Higgs basis note of Aug/15.
• 14.07.2015 - v1.0: release version (based on the Higgs basis note (Jun/14)).