Changes between Version 27 and Version 28 of SMEFT


Ignore:
Timestamp:
Sep 17, 2017, 9:24:43 PM (8 years ago)
Author:
Ilaria Brivio
Comment:

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  • SMEFT

    v27 v28  
    1717
    1818The SMEFT is constructed out of a series of SU(3),,C,, × SU(2),,L,, × U(1),,Y,, invariant (local and analytic) higher dimensional operators L,,6,,, L,,7,,, ... built out of the SM fields.
     19The SMEFTsim package provides a complete implementation of the dimension-6 Lagrangian adopting the Warsaw basis [https://arxiv.org/abs/1008.4884]
    1920
    20 The SMEFTsim package provides a complete implementation of the dimension-6 Lagrangian adopting the Warsaw basis [https://arxiv.org/abs/1008.4884] and it is designed to enable numerical studies of the LO interference of the SMEFT with the SM, while neglecting NLO corrections.
     21The SM Lagrangian is extended with the inclusion of the complete set of baryon-number-conserving operators of the Warsaw basis and of the SM loop-induced  Higgs couplings to gg, γγ and Zγ.
     22Importantly, field rotations required to have canonically normalized kinetic terms and parameter redefinitions following from the choice of an input parameters set are automatically applied in the Lagrangian.
    2123
    22 The SM Lagrangian is extended with the inclusion of the complete set of baryon-number-conserving operators of the Warsaw basis and of the SM loop-induced  Higgs couplings to gg, γγ and Zγ. The code assumes unitary gauge: in particular, modifications of the ghost Lagrangian have not been included.
    23 Importantly, field rotations required to have canonically normalized kinetic terms and parameter redefinitions following from the choice of an input parameters set are automatically applied in the Lagrangian.
    2424
    2525The SMEFTsim package provides implementations for 3 different flavor assumptions and 2 input scheme choices, for a total of 6 different models.
    … …  
    3434* m,,W,, scheme: {m,,W,,, m,,Z,, , G,,f,,}
    3535
     36Two independent sets (A and B) are supplied. Each set contains a main file, a number of subroutines and restriction files.
     37Pre-exported UFO files to be interfaced with MadGraph5_aMC@NLO can also be downloaded on this page (see Table below).
     38
     39Note that the two sets differ in the structure and in the technical implementation of L,,6,,, but they produce consistent results. The use of both sets is recommended for debugging and validation of the numerical results.
     40
     41We appreciate if you could report us any inconsistency or bugs.
    3642
    3743
    38 each set contains a main file, a number of subroutines and restriction files.
    39 Pre-exported UFO files to be interfaced with MadGraph5_aMC@NLO can also be downloaded from this page.
     44== Usage recommendations ==
    4045
     46The SMEFTsim package is designed to enable numerical studies of the LO interference of the SMEFT with the SM, while neglecting NLO corrections.
     47In this spirit, it has not been optimized for loop calculations in the SM or in the SMEFT. In particular:
    4148
     49* the Lagrangian assumes unitary gauge. Using it in R,,xi or Feynman gauge may lead to inconsistent results, as the ghost Lagrangian have not been modified to account for L,,6 corrections.
    4250
    43 The SMEFTsim package is to provide a complete tool for the analysis of the tree level interference terms between the L,,6,, dependent amplitude and the SM amplitudes in a measured process. In this spirit, we stress that this package is neither to be employed for the extraction of accurate SM predictions nor equipped for NLO calculations in MadGraph5_aMC@NLO.
    44 
    45 The models are built upon the default SM implementation in FeynRules, from which they inherit the SM fields, parameters and Lagrangian definitions. The original file has been extended and modified to include the complete set of L,,6,, baryon number conserving operators of the Warsaw basis. The loop-induced effective couplings of SM Higgs to gg, γγ and Zγ have also been included. At this stage, the ghost Lagrangian has been left in its SM form. The entire Wilson coefficient parameter space of the L,,6,, SMEFT and the automatic inclusion of the shifts due to the choice of an input parameters set are implemented.
    46 
    47 Two independent sets are supplied in the SMEFTsim package. Each set contains a single master code and a number of subroutines, along with several restriction files. The model file can be loaded in FeynRules using the notebook program, with the product of the UFOs.
    48 Model files and pre-exported UFO files to be interfaced with MadGraph5_aMC@NLO can be downloaded on this page.
    49 
    50 
    51 Note that the two sets differ in the structure and in the technical implementation of L,,6,,, but they produce consistent results. The use of both sets is recommended for debugging and validation of the numerical results. We appreciate if you could report us any inconsistency or bugs.
     51* the UFO files are not suitable for NLO evaluation in MadGraph5_aMC@NLO
    5252
    5353
    … …  
    7676----
    7777
    78 == UFO generated files ==
     78== Pre-exported UFO files (include restriction cards) ==
    7979 
    8080||                          ||    Set A  ||  || Set B || ||