Model : VLQ (Model-Independent) (at 2014-05-05 08:57:06)


Mathieu Buchkremer ( ; Giacomo Cacciapaglia ( ; Aldo Deandrea ( ; Luca Panizzi (

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[1] Nucl.Phys. B876 (2013) 376-417 ; M. Buchkremer, G. Cacciapaglia, A. Deandrea, L. Panizzi ; Model Independent Framework for Searches of Top Partners


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 [2].


As a generic framework, the four Vector-Like states X (Q=5/3), T (2/3), B (-1/3) and Y (-4/3) are introduced as new spin 1/2 class members coupling generically to any of the SM quark generations. Each class defines a specific top partner with a fixed electric charge, without any assumption on the other quantum numbers. Together with the new fermion fields definitions, the following interactions are added to the SM Lagrangian given in [2]. The new user-defined parameters consist of: -the KAPPA block : the top partners coupling strengths (set to 1 by default), -the MASS block : the corresponding quark masses (set to 600 GeV by default), -the DECAY block : the corresponding total widths (see the note below), -the XI block : the corresponding branching ratios into W, Z, and Higgs bosons, -the ZETA block : all top partners couplings to the three SM quark generations.
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