Article

• ##### Olivier Mattelaer
10/2008; DOI: 10.1063/1.3052056
Source: arXiv

ABSTRACT We here present some recent developments of MadGraph/MadEvent since the latest published version, 4.0. These developments include: Jet matching with Pythia parton showers for both Standard Model and Beyond the Standard Model processes, decay chain functionality, decay width calculation and decay simulation, process generation for the Grid, a package for calculation of quarkonium amplitudes, calculation of Matrix Element weights for experimental events, automatic dipole subtraction for next-to-leading order calculations, and an interface to FeynRules, a package for automatic calculation of Feynman rules and model files from the Lagrangian of any New Physics model.

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##### Article: Phenomenology of the Higgs Effective Lagrangian via FeynRules
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ABSTRACT: The Higgs discovery and the lack of any other hint for new physics favor a description of non-standard Higgs physics in terms of an effective field theory. We present an implementation of a general Higgs effective Lagrangian containing operators up to dimension six in the framework of FeynRules and provide details on the translation between the mass and interaction bases, in particular for three- and four-point interaction vertices involving Higgs and gauge bosons. We illustrate the strengths of this implementation by using the UFO interface of FeynRules capable to generate model files that can be understood by the MadGraph 5 event generator and that have the specificity to contain all interaction vertices, without any restriction on the number of external legs or on the complexity of the Lorentz structures. We then investigate several new physics effects in total rates and differential distributions for different Higgs production modes, including gluon fusion, associated production with a gauge boson and di-Higgs production. We finally study contact interactions of gauge and Higgs bosons to fermions.
10/2013;
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##### Article: Constraining $\tau$-lepton dipole moments and gluon couplings at the LHC
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ABSTRACT: We study the constraints that can be placed on anomalous $\tau$-lepton couplings at the LHC. We use an effective Lagrangian description for physics beyond the standard model which contains the $\tau$-lepton anomalous magnetic moment, electric dipole moment and weak dipole moments in two operators of dimension six. We include in our study two additional operators of dimension eight that directly couple the $\tau$-leptons to gluons and are therefore enhanced at the LHC. We consider the two main effects from these couplings: modifications to the Drell-Yan cross-section and to the $\tau$-lepton pair production in association with a Higgs boson. We find that a measurement of the former at the 14% level can produce constraints comparable to existing ones for the anomalous dipole couplings; and that a bound on the latter at a sensitivity level of $500\ \sigma_{SM}$ or better would produce the best constraint on the $\tau$-gluonic couplings.
Physical Review D 05/2013; 88. · 4.69 Impact Factor
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##### Article: Computing decay rates for new physics theories with FeynRules and MadGraph5/aMC@NLO
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ABSTRACT: We present new features of the FeynRules and MadGraph5/aMC@NLO programs for the automatic computation of decay widths that consistently include channels of arbitrary final-state multiplicity. The implementations are generic enough so that they can be used in the framework of any quantum field theory, possibly including higher-dimensional operators. We extend at the same time the conventions of the Universal FeynRules Output (or UFO) format to include decay tables and information on the total widths. We finally provide a set of representative examples of the usage of the new functions of the different codes in the framework of the Standard Model, the Higgs Effective Field Theory, the Strongly Interacting Light Higgs model and the Minimal Supersymmetric Standard Model and compare the results to available literature and programs for validation purposes.
02/2014;