JetRecursiveSoftDrop.h

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
 
// JetRecursiveSoftDrop.h
 
#ifndef JetRecursiveSoftDrop_H
#define JetRecursiveSoftDrop_H
 
// Jennifer Roloff & Joe Taenzer
// August 2017
//
// Tool to groom jets with recursive softdrop.
// SoftDrop is described in this paper: arXiv:1402.2657
// Recursive SoftDrop is described in this Boost2017 contribution: https://indico.cern.ch/event/579660/contributions/2582124/
// See also: https://fastjet.hepforge.org/trac/browser/contrib/contribs/RecursiveTools/tags/2.0.0-beta1/RecursiveSoftDrop.hh
 
#include "AsgTools/AsgTool.h"
#include "JetInterface/IJetGroomer.h"
#include "JetInterface/IJetFromPseudojet.h"
#include "AsgTools/ToolHandle.h"
 
#include "fastjet/ClusterSequence.hh"
#include "fastjet/contrib/RecursiveSymmetryCutBase.hh"
#include "fastjet/contrib/RecursiveSoftDrop.hh"
 
class JetRecursiveSoftDrop
: public asg::AsgTool,
  virtual public IJetGroomer {
ASG_TOOL_CLASS(JetRecursiveSoftDrop, IJetGroomer)
 
public:
 
  // Ctor.
  JetRecursiveSoftDrop(const std::string& name);
 
  // Dtor.
  ~JetRecursiveSoftDrop();
 
  // Initilization.
  StatusCode initialize();
 
  // Groom a jet and add result to a container.
  int groom(const xAOD::Jet& jin,
            const PseudoJetContainer&,
            xAOD::JetContainer& jout) const;
 
  // Dump to log.
  void print() const;
 
private:  // data
 
  // Job options.
  // Recursive SoftDrop algorithm:
  // z > zcut * (dR12/R0)^beta
  // z = min(pT1, pT2)/(pT1+pT2)
  // R0 = characteristic jet radius
  // N : algorithm terminates after passing SoftDrop condition N times 
  // (Standard SoftDrop terminates after passing it once)
  float m_zcut;                        // pT fraction for retaining subjets
  float m_beta;                        // How much to consider angular dependence
  int m_N;                        // Number of layers (-1 <> infinite)
  float m_R0;                            // Normalization of angular distance, usually the characteristic jet radius (default R0 = 1)
  ToolHandle<IJetFromPseudojet> m_bld;  // Tool to build jets.
 
};
 
#endif