We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5 aMC@NLO, capable of handling all these computations — parton-level fixed order, shower-matched, merged — in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV e + e − collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.

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The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations

FeynRules 2.0 - A complete toolbox for tree-level phenomenology

In this work we illustrate the POWHEG BOX, a general computer code framework for implementing NLO calculations in shower Monte Carlo programs according to the POWHEG method. Aim of this work is to provide an illustration of the needed theoretical ingredients, a view of how the code is organized and a description of what a user should provide in order to use it.

/pdf/a-general-framework-for-implementing-nlo-calculations-in-33rdilxwli.pdf

A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX

The anatomy of electroweak symmetry breaking: Tome I: The Higgs boson in the Standard Model

FeynRules - Feynman rules made easy

Two program packages are presented for evaluating one-loop amplitudes. They can work either in dimensional regularization or in constrained differential renormalization. The latter method is found at the one-loop level to be equivalent to regularization by dimensional reduction.

T. Hahn

Papers

Automatized One-Loop Calculations in 4 and D dimensions