1 | | === VLQ page === |

| 1 | == VLQ Model == |

| 2 | |

| 3 | === Authors === |

| 4 | |

| 5 | * Mathieu Buchkremer |

| 6 | * Universite catholique de Louvain (CP3) |

| 7 | * mathieu.buchkremer@uclouvain.be |

| 8 | |

| 9 | * Giacomo Cacciapaglia |

| 10 | * Universite de Lyon (CNRS/IN2P3) |

| 11 | * g.cacciapaglia@ipnl.in2p3.fr |

| 12 | |

| 13 | * Aldo Deandrea |

| 14 | * Universite de Lyon (CNRS/IN2P3) |

| 15 | * deandrea@ipnl.in2p3.fr |

| 16 | |

| 17 | * Luca Panizzi |

| 18 | * University of Southampton (School of Physics and Astronomy) |

| 19 | * l.panizzi@soton.ac.uk |

| 20 | |

| 21 | === Description === |

| 22 | |

| 23 | This model is an extension of the Standard Model (SM) with new top partners, intended for model-independent searches of vector-like quarks. The corresponding FeynRules implementation is based on a minimal effective Lagrangian description, which provides a direct connection between experimental observables and the new quark couplings. All fields and parameters are defined accordingly to the parameterisation detailed in [1]. The particle content, Feynman rules and parameters of the model are summarized in Parameters.pdf. |

| 24 | |

| 25 | === Model Implementation === |

| 26 | As a generic framework, the four states $X_{5/3}$, $T_{2/3}$, $B_{-1/3}$ and $Y_{-4/3}$ are introduced as new spin 1/2 class members. Each class defines a specific top partner with a fixed electric charge, without any assumption on the other quantum numbers. The model files are designed to allow for a straightforward extension to additional vector-like fermions, simply by adding the new particles to the corresponding class (F[5], F[6], F[7] and F[8] for $X_{5/3}$, $T_{2/3}$, $B_{-1/3}$ and $Y_{-4/3}$ type quarks, respectively). Particles embedded in larger SU(2) representations may also be introduced under new classes, following the same model-independent prescription. |

| 27 | |

| 28 | Together with the new fermion fields definitions, the following interactions are added to the SM Lagrangian |