Changes between Version 8 and Version 9 of MUED


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Timestamp:
11/10/10 10:09:49 (9 years ago)
Author:
PriscilaAquino
Comment:

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  • MUED

    v8 v9  
    99=== Description of the model & references ===
    1010
    11 One popular aproach to solve the Hierarchy Problem of the Standard Model is to extend space-time to higher dimensions. In this framework, the usual four-dimensional space-time is contained in a four-dimensional brane embedded in a large structure with N additional dimensions, the bulk.
     11One popular approach to solve the Hierarchy Problem of the Standard Model is to extend space-time to higher dimensions. In this framework, the usual four-dimensional space-time is contained in a four-dimensional brane embedded in a large structure with N additional dimensions, the bulk.
    1212
    13 Here, we shall focus on the Universal Extra Dimensional theory, in which the usual Standard Model particles are free to propagate in the bulk. As a consequence, these particles will be seem on the effective theory as a tower of N 4-dimensional particles with the same quantum numbers, but with increasing masses. This is called the Kaluza-Klein tower. Momentum conservation in the 5-dimensional space-time generates a conserved Kaluza-Klein number, which implies that different Kaluza-Klein modes can not mix with eachother.
     13Here, we shall focus on the Universal Extra Dimensional theory, in which the usual Standard Model particles are free to propagate in the bulk. As a consequence, these particles will be seem on the effective theory as a tower of N 4-dimensional particles with the same quantum numbers, but with increasing masses. This is called the Kaluza-Klein tower. Momentum conservation in the 5-dimensional space-time generates a conserved Kaluza-Klein number, which implies that different Kaluza-Klein modes can not mix with each other.
    1414
    15 In this implementation, a theory with five dimensions is considered, in which the fifth dimension is spatial and compactified on a S1/Z2 orbifold of radius R. We start from the most general five-dimensional Lagrangian. FeynRules derives the four-dimensional lagrangian automatically by imposing dimensional reduction and integratig out the extra-coordinate y.
     15In this implementation, a theory with five dimensions is considered, in which the fifth dimension is spatial and compactified on a S1/Z2 orbifold of radius R. We start from the most general five-dimensional Lagrangian. FeynRules derives the four-dimensional lagrangian automatically by imposing dimensional reduction and integrating out the extra-coordinate y.
    1616
    1717The minimal Universal extra dimensional model is given in:
     
    4747In order to validate our implementation, we have checked 118 processes using a center-of-mass energy of 1400 GeV. It was done the following way:
    4848   * '''Comparison of the built-in Madgraph Standard-Model and FeynRules generated''' '''Madgraph''' '''MUED for Standard Model''' '''processes.''' This comparison was done using squared matrix element at given phase-space points.
    49    * '''Comparison of the existing''' '''CalcHEP''' '''MUED (CH-ST) with the FeynRules generated ones in''' '''CalcHEP''' *,* '''Madgraph''' '''and Sherpa: CH-FR, MG-FR and SH-FR,''' through the calculation of several '''2-to-2''' cross-sections. All the checks performed were conclusive.
     49   * '''Comparison of the existing''' '''CalcHEP''' '''MUED (CH-ST) with the FeynRules generated ones in''' '''CalcHEP''', '''Madgraph''' '''and Sherpa: CH-FR, MG-FR and SH-FR,''' through the calculation of several '''2-to-2''' cross-sections. All the checks performed were conclusive.
    5050
    51    * Validation Table - SM + Fermions (Cross sections given in pb): ValidationMUED.jpg
     51   * Validation Table - SM + Fermions (Cross sections given in pb): [/attachment/wiki/MUED/ValidationMUED.jpg ValidationMUED.jpg]
    5252
    53    * Validation Table - Gauge (Cross sections given in pb): ValidationGauge.jpg
     53   * Validation Table - Gauge (Cross sections given in pb): [/attachment/wiki/MUED/ValidationGauge.jpg ValidationGauge.jpg]
    5454
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