The FastJet package is a fast implementation of the kt and Aachen/Cambridge jet clustering algorithms. Since v2.0, it also provides an interface to external jet algorithms (e.g. SISCone) through a plugin system. It was originally designed by Gavin Salam and Matteo Cacciari. I have joined them since FastJet v2.2 (June 2007).
This is an area where we gather 3rd-party contributions to FastJet. Although individual contributions are maintained by their own authors, the "FastJet team" has developed the generic interface (similar to a package manager) and provide some level of Quality Assessment to guarantee a minimal standard and degree of coherence over teh whole project.
Seedless Infrared Safe Cone algorithm developed with Gavin Salam. This is a jet-reconstruction algorithm belonging to the class of cone algorithms. Its main characteristic is its infrared safety, while keeping the processing time reasonnable for real-life applications. On the one side, the cone algorithms used today (e.g. the CDF midpoint algorithm) are not stable upon addition of soft particles. This infrared unsafety is not compatible with QCD, especially in today's accelerators where underlying events and piling-up bring lots of such soft particles. The main idea of our approach is a full, seedless, determination of all stable cones. On the other hand, previous seedless algorithms had a computation time of order N2N for N particles. SISCone's complexity is only polynomial and of order N2 log(N).
For details, see the SISCone webpage.
- Jet quality:
This is an interactive webpage that allows you to observe the effect of varying the jet definition on the reconstruction of heavy objects decaying to dijets at the LHC. It illustrates the importance of carefully choosing the appropriate jet definition for a given process and at a given scale. For more details, see the corresponding paper.