Rivet::PxConePlugin Class Reference

#include <PxConePlugin.hh>

Inheritance diagram for Rivet::PxConePlugin:

Public Member Functions
	PxConePlugin (double cone_radius_in, double min_jet_energy_in=5.0, double overlap_threshold_in=0.5, bool E_scheme_jets_in=false)
double	cone_radius () const
	the cone radius
double	min_jet_energy () const
double	overlap_threshold () const
	Maximum fraction of overlap energy in a jet – called ovlim in pxcone.
bool	E_scheme_jets () const
virtual std::string	description () const
virtual void	run_clustering (fastjet::ClusterSequence &) const
virtual double	R () const
	the plugin mechanism's standard way of accessing the jet radius

Detailed Description

Implementation of the PxCone algorithm (plugin for fastjet v2.1 upwards)

PxConePlugin is a plugin for fastjet (v2.1 upwards) that provides an interface to the fortran pxcone iterative cone algorithm with midpoint seeds.

Pxcone was written by Luis del Pozo and Michael H. Seymour. It is not a "supported" program, so if you encounter problems, you are on your own...

Note that pxcone sometimes encounters non-stable iterations; in such cases it returns an error – the plugin propagates this by throwing a fastjet::Error exception; if the user wishes to have robust code, they should catch this exception.

Pxcone has a hard-coded limit (by default 4000) on the maximum number of particles and protojets; if the number of particles or protojets exceeds this, again a fastjet::Error exception will be thrown.

The functionality of pxcone is described at http://www.hep.man.ac.uk/u/wplano/ConeJet.ps

Constructor & Destructor Documentation

PxConePlugin()

Rivet::PxConePlugin::PxConePlugin ( double  cone_radius_in, double  min_jet_energy_in = 5.0, double  overlap_threshold_in = 0.5, bool  E_scheme_jets_in = false  )

inline

constructor for the PxConePlugin, whose arguments have the following meaning:

• the cone_radius is as usual in cone algorithms
• stables cones (protojets) below min_jet_energy are discarded before calling the splitting procedure to resolve overlaps (called epslon in pxcone).
• when two protojets overlap, if (overlapping_Et)/(Et_of_softer_protojet) < overlap_threshold the overlapping energy is split between the two protojets; otherwise the less energetic protojet is discarded. Called ovlim in pxcone.
• pxcone carries out p-scheme recombination, and the resulting jets are massless; setting E_scheme_jets = true (default false) doesn't change the jet composition, but the final momentum sum for the jets is carried out by direct four-vector addition instead of p-scheme recombination.

Member Function Documentation

E_scheme_jets()

bool Rivet::PxConePlugin::E_scheme_jets ( ) const

inline

if true then the final jets are returned as the E-scheme recombination of the particle momenta (by default, pxcone returns massless jets with a mean phi,eta type of recombination); regardless of what is returned, the internal pxcone jet-finding procedure is unaffected.

min_jet_energy()

double Rivet::PxConePlugin::min_jet_energy ( ) const

inline

minimum jet energy (protojets below this are thrown own before merging/splitting) – called epslon in pxcone

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The documentation for this class was generated from the following files:

• include/Rivet/Projections/PxConePlugin.hh
• src/Projections/PxConePlugin.cc