CP3 Lunch - MadWeight: automatic reweighting of experimental events - Pierre Artoisenet

by Pierre Artoisenet (UCL)

Wednesday 1 Oct 2008, 13:00 → 13:50 Europe/Brussels

Cycl.06

In this talk, I will first review the matrix element method, which has been intensively used at the Tevatron during the passed few years, either to disentangle signal from background events or to measure accurately particle properties in decay-chain processes. In this method one discriminates between different theoretical assumptions by defining a weight for each experimental event, based on the squared matrix element. As this technique makes use of the whole information reconstructed from the detector, it is particularly suitable for the analysis of low statistics events and/or experimental signatures characterized by a large amount of missing transverse energy. Although the definition of these weights is conceptually simple, their numerical evaluations require to use a process-dependent phase-space generator, tuned to the resolution of the detector. MadWeight -which I will present in the second part of the talk- is an algorithm that creates automatically the appropriate phase-space generator, given an arbitrary decay-chain process and the resolution function. After introducing the basic idea of the code, I will mention its capabilities and illustrate them with several examples of application.