Page MenuHomeHEPForge
Files F10227124

example_mmdt_ee.cc
No OneTemporary
Actions

example_mmdt_ee.cc
View Options

//----------------------------------------------------------------------
/// \file example_ee.cc
///
/// This example program is meant to illustrate how to use
/// RecursiveTools for e+e- events. It is done using the
/// ModifiedMassDropTagger class but the same strategy would work as
/// well for SoftDrop, RecursiveSoftDrop and IteratedSoftDrop
///
/// Run this example with
///
/// \verbatim
/// ./example_ee < ../data/single-ee-event.dat
/// \endverbatim
//----------------------------------------------------------------------
// $Id: example_mmdt_ee.cc 1064 2017-09-08 09:19:57Z gsoyez $
//
// Copyright (c) 2017-, Gavin P. Salam, Gregory Soyez, Jesse Thaler,
// Kevin Zhou, Frederic Dreyer
//
//----------------------------------------------------------------------
// This file is part of FastJet contrib.
//
// It is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at
// your option) any later version.
//
// It is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this code. If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------
#include <iostream>
#include <sstream>
#include <sstream>
#include <iomanip>
#include <cmath>
#include "fastjet/ClusterSequence.hh"
#include "fastjet/tools/Filter.hh"
#include "ModifiedMassDropTagger.hh" // In external code, this should be fastjet/contrib/ModifiedMassDropTagger.hh
using namespace std;
using namespace fastjet;
// forward declaration to make things clearer
void read_event(vector<PseudoJet> &event);
ostream & operator<<(ostream &, const PseudoJet &);
//----------------------------------------------------------------------
int main(){
//----------------------------------------------------------
// read in input particles
vector<PseudoJet> event;
read_event(event);
cout << "# read an event with " << event.size() << " particles" << endl;
// first get some Cambridge/Aachen jets
double R = 1.0;
JetDefinition jet_def(ee_genkt_algorithm, R, 0.0);
ClusterSequence cs(event, jet_def);
double Emin = 10.0;
Selector sel_jets = SelectorEMin(Emin);
vector<PseudoJet> jets = sorted_by_E(sel_jets(cs.inclusive_jets()));
// give the tagger a short name
typedef contrib::ModifiedMassDropTagger MMDT;
// This version uses the following setup:
// - use energy for the symmetry measure
// Note: since the mMDT does not require angular information,
// here we could use either theta_E or cos_theta_E (it would
// only change the value of DeltaR). For
// SoftDrop/RecursiveSoftDrop/IteratedSoftDrop, this would make
// a difference and we have
// DeltaR_{ij}^2 = theta_{ij}^2 (theta_E)
// DeltaR_{ij}^2 = 2 [1-cos(theta_{ij}^2)] (cos_theta_E)
//
// - recurse into the branch with the largest energy
//
// - use a symmetry cut, with no mass-drop requirement
double z_cut = 0.20;
MMDT tagger(z_cut,
MMDT::cos_theta_E,
std::numeric_limits<double>::infinity(),
MMDT::larger_E);
cout << "tagger is: " << tagger.description() << endl;
for (unsigned ijet = 0; ijet < jets.size(); ijet++) {
// first run MMDT and examine the output
PseudoJet tagged_jet = tagger(jets[ijet]);
cout << endl;
cout << "original jet: " << jets[ijet] << endl;
cout << "tagged jet: " << tagged_jet << endl;
if (tagged_jet == 0) continue; // If symmetry condition not satisified, jet is not tagged
cout << " delta_R between subjets: " << tagged_jet.structure_of<MMDT>().delta_R() << endl;
cout << " symmetry measure(z): " << tagged_jet.structure_of<MMDT>().symmetry() << endl;
cout << " mass drop(mu): " << tagged_jet.structure_of<MMDT>().mu() << endl;
cout << endl;
}
return 0;
}
//----------------------------------------------------------------------
/// read in input particles
void read_event(vector<PseudoJet> &event){
string line;
while (getline(cin, line)) {
istringstream linestream(line);
// take substrings to avoid problems when there are extra "pollution"
// characters (e.g. line-feed).
if (line.substr(0,4) == "#END") {return;}
if (line.substr(0,1) == "#") {continue;}
double px,py,pz,E;
linestream >> px >> py >> pz >> E;
PseudoJet particle(px,py,pz,E);
// push event onto back of full_event vector
event.push_back(particle);
}
}
//----------------------------------------------------------------------
/// overloaded jet info output
ostream & operator<<(ostream & ostr, const PseudoJet & jet) {
if (jet == 0) {
ostr << " 0 ";
} else {
ostr << " E = " << jet.pt()
<< " m = " << jet.m();
}
return ostr;
}

File Metadata

Mime Type
text/x-c
Expires
Thu, Apr 3, 8:01 PM (2 h, 59 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
4724727
Default Alt Text
example_mmdt_ee.cc (5 KB)

Event Timeline