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>
Public Types | |
| typedef MassDropTaggerStructure | StructureType |
| the type of the associated structure | |
 Public Types inherited from fastjet::Transformer | |
| typedef PseudoJetStructureBase | StructureType |
| A typedef that is needed to ensure that the PseudoJet::structure_of() template function works. | |
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()). More... | |
| Public Member Functions inherited from fastjet::Transformer | |
| Transformer () | |
| default ctor | |
| virtual | ~Transformer () |
| default dtor | |
| Public Member Functions inherited from fastjet::FunctionOfPseudoJet< PseudoJet > | |
| FunctionOfPseudoJet () | |
| default ctor | |
| virtual | ~FunctionOfPseudoJet () |
| default dtor (virtual to allow safe polymorphism) | |
| PseudoJet | operator() (const PseudoJet &pj) const |
| apply the function using the "traditional" () operator. More... | |
| std::vector< PseudoJet > | operator() (const std::vector< PseudoJet > &pjs) const |
| apply the function on a vector of PseudoJet, returning a vector of the results. More... | |
Protected Attributes | |
| double | _mu |
| double | _ycut |
Static Protected Attributes | |
| static LimitedWarning | _warnings_nonca |
| static LimitedWarning | _negative_mass_warning |
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
- undo the last step of the clustering step j -> j1 + j2 (label them such as j1 is the most massive).
- if there is a mass drop, i.e. m_j1/m_j < mu_cut, and the splitting is sufficiently symmetric,
, keep j as the result of the tagger (with j1 and j2 its 2 subjets) - 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:
- The first argument is the minimal mass drop that is required (mu_cut) [0.67 by default]
- The second argument is the asymmetry cut (y_cut) [0.09 by default]
Input conditions
- one must be able to successively "uncluster" the original jet using "has_parents"
Output/structure
- the 2 subjets are kept as pieces if some substructure is found, otherwise a single 0-momentum piece is returned
- the 'mu' and 'y' values corresponding to the unclustering step that passed the tagger's cuts
See also 12 - boosted Higgs tagging for a usage example.
Definition at line 92 of file MassDropTagger.hh.
Member Function Documentation
◆ result()
runs the tagger on the given jet and returns the tagged PseudoJet if successful, a PseudoJet==0 otherwise (standard access is through operator()).
- Parameters
-
jet the PseudoJet to tag
Implements fastjet::Transformer.
Definition at line 57 of file MassDropTagger.cc.
The documentation for this class was generated from the following files:
- tools/fastjet/tools/MassDropTagger.hh
- tools/MassDropTagger.cc
