Vector-leptoquark model

Authors

• Michael J. Baker
  • University of Melbourne
  • michael.baker AT unimelb.edu.au
• Javier Fuentes-Martín
  • Johannes Gutenberg University, Mainz
  • jfuentes AT uni-mainz.de
• Gino Isidori
  • UZH, Zurich
  • isidori AT physik.uzh.ch
• Matthias König
  • Technische Universität München
  • matthias.koenig AT tum.de

Description of the model

This model is an extension of the SM, featuring a vector leptoquark (U₁~(3,1)_2/3), a colored vector (G'~(8,1)₀), and a SM singlet (Z'~(1,1)₀) as new heavy mediators.
The implementation of the model is based on "High-p_T Signatures in Vector-Leptoquark Models" (​arXiv:1901.10480). If you use our model file please cite this reference.

Model Files

vector_LQ.fr: This is the Feynrules model file for the vector leptoquark.
coloron.fr: This is the Feynrules model file for the vector color-octet.
Zprime.fr: This is the Feynrules model file for the vector singlet.

Model Restrictions

Massless.rst: This restriction file sets all the masses and Yukawas to zero, except for the ones of the top quark (necessary to work in the 5 flavor scheme).

Instructions

The model is loaded by merging the model files SM.fr (in StandardModel), vector_LQ.fr, coloron.fr and Zprime.fr. Alternatively, one can exclude the model files coloron.fr or Zprime.fr if the user is not interested in these mediators.
The implementation allows for the use of the Feynman gauge in the SM. The switch between the two gauge is achieved via FeynmanGauge = True/False (see StandardModel).
The NP interaction order has been set to 1, the same as QCD.

Examples

model_gen.nb: This is an example Mathematica® notebook that loads the Feynrules model files and calculates the UFO model.
widths.nb: This is an example Mathematica® notebook that loads the Feynrules model files and calculates the Feynman rules and widths of the new vectors.

Interfaces

This model implementation is known to work with the following interfaces:

• FeynArts Interface
• MadGraph Interface

Validation

An alternative Feynrules implementation for the vector leptoquark model (but with interactions to left-handed third-generation SM fermions only) is available in ​https://lqnlo.hepforge.org. We have cross-checked our leptoquark implementation (with β_R³³ = 0) against this one, finding a perfect agreement between the two.

UFO model

vector_LQ_UFO.tar: UFO model including the U₁, G' and Z' .