MadGraph/MadEvent v4: the new web generation

Abstract

We present the latest developments of the MadGraph/MadEvent Monte Carlo event generator and several applications to hadron collider physics. In the current version events at the parton, hadron and detector level can be generated directly from a web interface, for arbitrary processes in the Standard Model and in several physics scenarios beyond it (HEFT, MSSM, 2HDM). The most important additions are: a new framework for implementing user-defined new physics models; a standalone running mode for creating and testing matrix elements; generation of events corresponding to different processes, such as signal(s) and backgrounds, in the same run; two platforms for data analysis, where events are accessible at the parton, hadron and detector level; and the generation of inclusive multi-jet samples by combining parton-level events with parton showers. To illustrate the new capabilities of the package some applications to hadron collider physics are presented:I. Higgs search in pp → H → W + W − : signal and backgrounds. II. Higgs CP properties: pp → Hjj in the HEFT. III. Spin of a new resonance from lepton angular distributions. IV. Single-top and Higgs associated production in a generic 2HDM. V. Comparison of strong SUSY pair production at the SPS points. VI. Inclusive W +jets matched samples: comparison with the Tevatron data.

Search for physics beyond the standard model in final states with a lepton and missing transverse energy in proton-proton collisions ats=8 TeV

“…A model of a W 0 -boson with a SM-like left-handed coupling has been implemented within the MADGRAPH 4.5.1 event generator [58]. This model includes spin correlations as well as finite-width effects.…”

Singlet scalars as Higgs boson imposters at the Large Hadron Collider

“…To determine the reach in the S → γγ mode we analyze events at √ s = 7 and 14 TeV up to 10 fb −1 and 100 fb −1 of integrated luminosity, respectively. For pp → S → γγ, we generate events in MadEvent with an effective hgg and hγγ coupling [29]. The irreducible background to the diphoton signal is the continuum γγ process.…”

Higgs boson production in association with top quarks in the POWHEG BOX

“…The tree-level amplitudes can 3 be generated with the help of the build tool based on MadGraph 4 [47,48] that is available in the POWHEG BOX [49]. For pp → ttH, we use the virtual amplitudes of [22][23][24][25] and adapt them to the format required by the POWHEG BOX.…”