Native tools | 3rd party tools | Native algorithms | Plugins

Starting from version 3 FastJet introduces a number of tools meant to facilitate the analysis of events and of jet substructure. A schematic view of these tools is provided below. In addition many other tools are available through the FastJet Contrib package.

Users of FastJet 2 can refer to this page, where a number of external codes implementing some of the same tools are described and linked to.

Native tools

Tool Available since
FastJet version
Generic tools
Filter 3.0 arXiv:0802.2470 + Trimming (arXiv:0810.1304) [1]
Pruner 3.0 arXiv:0903.5081 [2]
Boost/Unboost 3.0
Recluster 3.1
Background estimation and subtraction
JetMedianBackgroundEstimator 3.0 [3]
GridMedianBackgroundEstimator 3.0
Subtractor 3.0
MassDropTagger 3.0 arXiv:0802.2470 [4]
CASubJetTagger 3.0 arXiv:0906.0728 [5]
RestFrameNSubjettinessTagger 3.0 arXiv:1011.1493
JHTopTagger 3.0 arXiv:0806.0848

  1. For older versions of FastJet use Filter.hh and for filtering and see the authors' web-site for trimming. See also see example/ in earlier versions of FastJet
  2. For earlier versions of FastJet, use the plugin from pruning authors' web site
  3. Superseeds the background estimation through ClusterSequenceArea in earlier versions of FastJet
  4. For older versions of fastjet, see example/, which also illustrates the filtering step
  5. Use CASubJet.hh with older versions of FastJet

3rd party tools (external code)

A wide range of 3rd-party tools is available from the fastjet-contrib project (see list). A few tools exist only outside of fastjet-contrib:

Code Authors Comment Available in FastJet Contrib
YSplitter Butterworth, Cox and Forshaw Just call the ClusterSequence::exclusive_subdmerge(...) method on your jet. --
HEPTopTagger Plehn, Salam, Spannowsky and Takeuchi based on arXiv:0910.5472 and arXiv:1006.2833 N
multivariate W-jet Cui, Han and Schwartz arXiv:1012.2077 N
Qjets Ellis, Hornig, Krohn, Roy and Schwartz arXiv:1201.1914 N
TemplateTagger Backovic, Juknevic and Perez arXiv:1212.2978, based on arXiv:1006.2035 N

Native jet algorithms

Algorithm Available since
FastJet version
longitudinally invariant kt 1.0
(inclusive) Cambridge/Aachen 2.0
anti-kt 2.2
gen-kt 2.4
e+e- kt and gen-kt 2.4


(some must be explicitly enabled at configure time)
Algorithm Available since
FastJet version
SISCone 2.1
CDF MidPoint 2.1 [IR(3+1) unsafe, deprecated]
CDF JetClu 2.1 [IR(2+1) unsafe, deprecated]
PxCone (fortran 77) 2.1 [IR(3+1) unsafe, deprecated]
D0 Run II Cone 2.4 [IR(3+1) unsafe, deprecated]
ATLAS Cone algorithm 2.4 [IR(2+1) unsafe, deprecated]
CMS Cone algorithm 2.4 [Coll(3+1) unsafe, deprecated]
TrackJet 2.4 [Coll(3+1) unsafe, deprecated]
e+e- (spherical) SISCone 2.4
e+e- JADE algorithm 2.4
e+e- Cambridge algorithm 2.4
Nested definitions 2.4
D0 Run I Cone 3.0 [IR(2+1) unsafe, deprecated]
GridJet 3.0