FastJet 3.0.4
Public Types | Public Member Functions | Protected Attributes | Static Protected Attributes
fastjet::MassDropTagger Class Reference

Class that helps perform 2-pronged boosted tagging using the "mass-drop" technique (with asymmetry cut) introduced by Jonathan Butterworth, Adam Davison, Mathieu Rubin and Gavin Salam in arXiv:0802.2470 in the context of a boosted Higgs search. More...

#include <fastjet/tools/MassDropTagger.hh>

Inheritance diagram for fastjet::MassDropTagger:
Inheritance graph
[legend]
Collaboration diagram for fastjet::MassDropTagger:
Collaboration graph
[legend]

List of all members.

Public Types

typedef MassDropTaggerStructure StructureType
 the type of the associated structure

Public Member Functions

 MassDropTagger (const double mu=0.67, const double ycut=0.09)
 default ctor
virtual std::string description () const
 returns a textual description of the tagger
virtual PseudoJet result (const PseudoJet &jet) const
 runs the tagger on the given jet and returns the tagged PseudoJet if successful, a PseudoJet==0 otherwise (standard access is through operator()).

Protected Attributes

double _mu
double _ycut

Static Protected Attributes

static LimitedWarning _warnings_nonca

Detailed Description

Class that helps perform 2-pronged boosted tagging using the "mass-drop" technique (with asymmetry cut) introduced by Jonathan Butterworth, Adam Davison, Mathieu Rubin and Gavin Salam in arXiv:0802.2470 in the context of a boosted Higgs search.

The tagger proceeds as follows:

0. start from a jet obtained from with the Cambridge/Aachen algorithm

1. undo the last step of the clustering step j -> j1 + j2 (label them such as j1 is the most massive).

2. if there is a mass drop, i.e. m_j1/m_j < mu_cut, and the splitting is sufficiently symmetric, ${\rm min}(p_{tj1}^2,p_{tj2}^2)\Delta R_{j1,j2}^2 > y_{\rm cut} m_j^2$, keep j as the result of the tagger (with j1 and j2 its 2 subjets)

3. otherwise, redefine j to be equal to j1 and return to step 1.

Note that in the original proposal, j1 and j2 are both required to be b-tagged and a filter (with Rfilt=min(0.3,Rbb/2) and n_filt=3) is also applied to j to obtain the final "Higgs candidate". See the example 12 - boosted Higgs tagging for details.

Options

The constructor has the following arguments:

Input conditions

Output/structure

See also 12 - boosted Higgs tagging for a usage example.

Definition at line 90 of file MassDropTagger.hh.


Member Function Documentation

PseudoJet fastjet::MassDropTagger::result ( const PseudoJet jet) const [virtual]

runs the tagger on the given jet and returns the tagged PseudoJet if successful, a PseudoJet==0 otherwise (standard access is through operator()).

Parameters:
jetthe PseudoJet to tag

Implements fastjet::Transformer.

Definition at line 54 of file MassDropTagger.cc.


The documentation for this class was generated from the following files:
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends