FastJet 3.0.5

Class that helps perform boosted top tagging using the "Johns Hopkins" method from arXiv:0806.0848 (Kaplan, Rehermann, Schwartz and Tweedie) More...
#include <fastjet/tools/JHTopTagger.hh>
Public Types  
typedef JHTopTaggerStructure  StructureType 
the type of the associated structure  
Public Member Functions  
JHTopTagger (const double delta_p=0.10, const double delta_r=0.19, double cos_theta_W_max=0.7, double mW=80.4)  
default ctor The parameters are the following:  
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, or a PseudoJet==0 otherwise (standard access is through operator()).  
Protected Member Functions  
std::vector< PseudoJet >  _split_once (const PseudoJet &jet_to_split, const PseudoJet &reference_jet) const 
runs the Johns Hopkins decomposition procedure  
Protected Attributes  
double  _delta_p 
double  _delta_r 
double  _cos_theta_W_max 
double  _mW 
Static Protected Attributes  
static LimitedWarning  _warnings_nonca 
Class that helps perform boosted top tagging using the "Johns Hopkins" method from arXiv:0806.0848 (Kaplan, Rehermann, Schwartz and Tweedie)
The tagger proceeds as follows:
A JHTopTagger can be used as follows:
double delta_p = 0.10; // subjets must carry at least this fraction of the original jet's p_t double delta_r = 0.19; // subjets must be separated by at least this Manhattan distance double cos_theta_W_max = 0.7; // the maximal allowed value of the W helicity angle JHTopTagger top_tagger(delta_p, delta_r, cos_theta_W_max); // indicate the acceptable range of top, W masses (default: no limits) top_tagger.set_top_selector(SelectorMassRange(150,200)); top_tagger.set_W_selector (SelectorMassRange( 65, 95)); // now try and tag a jet PseudoJet top_candidate = top_tagger(jet); // jet should come from a Cambridge/Aachen clustering if (top_candidate != 0) { // successful tagging double top_mass = top_candidate.m(); double W_mass = top_candidate.structure_of<JHTopTagger>().W().m(); }
The full set of information available from the structure_of<JHTopTagger>() call is
The structure of the top_candidate can also be accessed through its pieces() function:
The W itself has two pieces (corresponding to W1, W2).
The existence of the first two of the structural calls (W(), non_W()) and the fact that the top is made of two pieces (W, non_W) are features that should be common to all taggers derived from TopTaggerBase.
See also 13  boosted top tagging for a full usage example.
Definition at line 118 of file JHTopTagger.hh.
fastjet::JHTopTagger::JHTopTagger  (  const double  delta_p = 0.10 , 
const double  delta_r = 0.19 , 

double  cos_theta_W_max = 0.7 , 

double  mW = 80.4 

)  [inline] 
default ctor The parameters are the following:
delta_p  fractional pt cut imposed on the subjets (computed as a fraction of the original jet) 
delta_r  minimal distance between 2 subjets (computed as y1y2+phi1phi2) 
cos_theta_W_max  the maximal value for the polarisation angle of the W 
mW  the W mass 
The default values of all these parameters are taken from arXiv:0806:0848
Definition at line 132 of file JHTopTagger.hh.
runs the tagger on the given jet and returns the tagged PseudoJet if successful, or a PseudoJet==0 otherwise (standard access is through operator()).
jet  the PseudoJet to tag 
Implements fastjet::Transformer.
Definition at line 60 of file JHTopTagger.cc.