Changes between Version 2 and Version 3 of FAQ-NewPhysics-1


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Timestamp:
Apr 12, 2012, 10:51:26 AM (13 years ago)
Author:
Martin
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  • FAQ-NewPhysics-1

    v2 v3  
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    3 == How can I implement a new physics model in Software.MadGraph / Software.MadEvent ? ==
     3== How can I implement a new physics model in MadGraph / MadEvent ? ==
    44
    5 === The "old" way : using {{{
     5=== The "old" way : using
     6{{{
    67USRMOD
    7 }}} v1 ===
    8 This is "traditional" way to create a new physics model in Software.MadGraph / Software.MadEvent v4. You should use the {{{
     8}}}
     9v1 ===
     10This is "traditional" way to create a new physics model in MadGraph / MadEvent v4. You should use the
     11{{{
    912USRMOD
    10 }}} template directory present in the {{{
     13}}}
     14template directory present in the
     15{{{
    1116Models
    12 }}} directory. The full procedure to follow is extensively described [http://cp3wks05.fynu.ucl.ac.be/Manual/usrmod.html here].
     17}}}
     18directory. The full procedure to follow is extensively described [http://cp3wks05.fynu.ucl.ac.be/Manual/usrmod.html here].
    1319
    1420This method has been successfully used over the past to create several new Physics models. However, it presents two important disadvantages:
    15    * The base model is always the SM and the possible modifications are restricted (e.g. removing a particle is not possible). This was due to the important structural differences in the original BSM models provided with Software.MadGraph / Software.MadEvent v4.
     21   * The base model is always the SM and the possible modifications are restricted (e.g. removing a particle is not possible). This was due to the important structural differences in the original BSM models provided with MadGraph / MadEvent v4.
    1622   * Feynman rules should be computed by hand.
    17 To address these issues, two new methods are now available and should be preferentially used (starting from the future version 4.6, old models files, including those produced with the {{{
     23To address these issues, two new methods are now available and should be preferentially used (starting from the future version 4.6, old models files, including those produced with the
     24{{{
    1825USRMOD
    19 }}} v1, will only be passively supported).
     26}}}
     27v1, will only be passively supported).
    2028
    21 === The "new" way : using [http://feynrules.phys.ucl.ac.be FeynRules] and/or {{{
     29=== The "new" way : using [http://feynrules.phys.ucl.ac.be FeynRules] and/or
     30{{{
    2231USRMOD
    23 }}} v2 ===
     32}}}
     33v2 ===
    2434
    2535==== [http://feynrules.phys.ucl.ac.be FeynRules] ====
    2636According to the [http://feynrules.phys.ucl.ac.be FeynRules] website, "[http://feynrules.phys.ucl.ac.be FeynRules] is a Mathematica® package that allows the calculation of Feynman rules in momentum space for any QFT physics model. The user needs to provide FeynRules with the minimal information required to describe the new model, contained in the so-called model-file. This information is then used to calculate the set of Feynman rules associated with the Lagrangian. The Feynman rules calculated by the code can then be used to implement the new physics model into other existing tools, such as MC generators. This is done via a set of interfaces which are developed together and maintained by the corresponding MC authors."
    2737
    28 All interested users should report directly to the [http://feynrules.phys.ucl.ac.be FeynRules] website for more information on this convenient tool and on the associated [http://feynrules.phys.ucl.ac.be/view/Main/MadGraphInterface interface] for Software.MadGraph / Software.MadEvent.
     38All interested users should report directly to the [http://feynrules.phys.ucl.ac.be FeynRules] website for more information on this convenient tool and on the associated [http://feynrules.phys.ucl.ac.be/view/Main/MadGraphInterface interface] for MadGraph / MadEvent.
    2939
    30 Thanks to its high capabilities, including a user friendly interface, the automatized model generation for arbitrary QFT physics theories and robust validation procedures, [http://feynrules.phys.ucl.ac.be FeynRules] and the corresponding interface will be the default tool to generate important Software.MadGraph / Software.MadEvent models starting from version 4.6.
     40Thanks to its high capabilities, including a user friendly interface, the automatized model generation for arbitrary QFT physics theories and robust validation procedures, [http://feynrules.phys.ucl.ac.be FeynRules] and the corresponding interface will be the default tool to generate important MadGraph / MadEvent models starting from version 4.6.
    3141
    32 ==== {{{
     42====
     43{{{
    3344USRMOD
    34 }}} v2 ====
    35 In order to keep the {{{
     45}}}
     46v2 ====
     47In order to keep the
     48{{{
    3649USRMOD
    37 }}} approach flexibility with the new models produced by the [http://feynrules.phys.ucl.ac.be FeynRules] package, a new independent version of the {{{
     50}}}
     51approach flexibility with the new models produced by the [http://feynrules.phys.ucl.ac.be FeynRules] package, a new independent version of the
     52{{{
    3853USRMOD
    39 }}} scripts, called {{{
     54}}}
     55scripts, called
     56{{{
    4057USRMOD
    41 }}} v2, has been released. The "philosophy" remains the same, i.e. starting from a base model, the user add/remove/modify particles, interactions and/or parameters, then run the script and finally edit the relevant coupling expressions.
     58}}}
     59v2, has been released. The "philosophy" remains the same, i.e. starting from a base model, the user add/remove/modify particles, interactions and/or parameters, then run the script and finally edit the relevant coupling expressions.
    4260
    4361Compare to the first version, it has the following advantages:
    44    * Fully compatible with (and ''only'' with) all models produced by [http://feynrules.phys.ucl.ac.be FeynRules], so the base model can be the SM but also any other model previously produced, including those produced by the {{{
     62   * Fully compatible with (and ''only'' with) all models produced by [http://feynrules.phys.ucl.ac.be FeynRules], so the base model can be the SM but also any other model previously produced, including those produced by the
     63{{{
    4564USRMOD
    46 }}} v2 itself!
    47    * No limitation for the possible modifications. The {{{
     65}}}
     66v2 itself!
     67   * No limitation for the possible modifications. The
     68{{{
    4869USRMOD
    49 }}} v2 propose to first save a "copy" of the base model and adjust all files to reflects the user changes.
     70}}}
     71v2 propose to first save a "copy" of the base model and adjust all files to reflects the user changes.
    5072   * Safer thanks to additional internal consistency checks
    5173   * Evolutive object-oriented Python code