Changes between Version 16 and Version 17 of VLQ


Ignore:
Timestamp:
06/24/13 20:40:48 (6 years ago)
Author:
buchkremer
Comment:

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  • VLQ

    v16 v17  
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    42 All the above parameter classes are combined internally in the FeynRules model file [attachment:VLQ.fr] to match the model-independent prescription presented above [1]. The default parameter cards use the standard MadGraph  values for the SM input parameters, as given in [attachment:Parameters.pdf]. For consistency, all light quarks included in the proton definition are restricted to be massless (5F scheme) using the restriction file [attachment:Massless.rst] when loading the FeynRules model, except for the top, bottom and tau lepton masses. The default model loads the real 3X3 CKM matrix given in [attachment:Parameters.pdf] [2] as an external parameter. In general, the presence of new top partners induce model-dependent corrections to the mixings between the novel heavy fermions and the lighter quark families, and the SM electroweak couplings must be modified accordingly.
     42All the above parameter classes are combined internally in the FeynRules model file [attachment:VLQ.fr] to match the model-independent prescription presented above [1]. The default parameter cards use the standard MadGraph  values for the SM input parameters, as given in [attachment:Parameters.pdf]. The default configuration assumes a vector-like T singlet, mixing exclusively with the third generation. For consistency, all light quarks included in the proton definition are restricted to be massless (5F scheme) using the restriction file [attachment:Massless.rst] when loading the FeynRules model, except for the top, bottom and tau lepton masses. The default model loads the real 3X3 CKM matrix given in [attachment:Parameters.pdf] [2] as an external parameter. In general, the presence of new top partners induce model-dependent corrections to the mixings between the novel heavy fermions and the lighter quark families, and the SM electroweak couplings must be modified accordingly.
    4343
    4444'''Extension''': In addition to the above parameterisation, an extension including chromomagnetic couplings between VL and Standard Model quarks is provided in the file VLQ_Chromomagnetic.fr. The new couplings (typically generated at loop level in minimal SM extensions) are implemented in terms of the dimension 6 operator:
     
    6262Below we provide the tarballs containing the main model files and outputs. The model implementation is also known to work with the CalcHEP/CompHEP interfaces, which can be generated from the [attachment:VLQ.nb] Mathematica notebook. Although FeynRules now supports exclusively the version 5 of MadGraph (UFO format, in the unitary gauge), the MadGraph4 model files can be provided on demand.
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    64 To import the model into MadGraph, it is enough to untar the UFO directory into the models subdirectory of MadGraph, and load the model using the "import model VLQ_UFO" command.
     64To import the model into MadGraph, it is enough to untar the UFO directory into the models subdirectory of MadGraph, and load the model using the "import model VLQ_UFO" command. Note : by default, the model files assume a vector-like T singlet mixing exclusively with the third generation, as described in [attachment:Parameters.pdf]. 
    6565
    6666 * [attachment:VLQ.fr] : FeynRules main file.