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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/PromptFinalState.hh"
#include "Rivet/Projections/FastJets.hh"
namespace Rivet {
/// @brief Isolated triphotons at 8 TeV
class ATLAS_2017_I1644367 : public Analysis {
public:
// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2017_I1644367);
// Book histograms and initialise projections before the run
void init() {
const FinalState fs;
declare(fs, "FS");
FastJets fj(fs, FastJets::KT, 0.5);
fj.useJetArea(new fastjet::AreaDefinition(fastjet::VoronoiAreaSpec()));
declare(fj, "KtJetsD05");
PromptFinalState photonfs(Cuts::abspid == PID::PHOTON && Cuts::abseta < 2.37 && Cuts::pT > 15*GeV);
declare(photonfs, "Photon");
// Histograms
book(_h["etg1"] , 1, 1, 1);
book(_h["etg2"] , 2, 1, 1);
book(_h["etg3"] , 3, 1, 1);
book(_h["dphig1g2"], 4, 1, 1);
book(_h["dphig1g3"], 5, 1, 1);
book(_h["dphig2g3"], 6, 1, 1);
book(_h["detag1g2"], 7, 1, 1);
book(_h["detag1g3"], 8, 1, 1);
book(_h["detag2g3"], 9, 1, 1);
book(_h["mg1g2"] , 10, 1, 1);
book(_h["mg1g3"] , 11, 1, 1);
book(_h["mg2g3"] , 12, 1, 1);
book(_h["mg1g2g3"] , 13, 1, 1);
}
// Perform the per-event analysis
void analyze(const Event& event) {
// Require at least 2 photons in final state
const Particles photons = apply<PromptFinalState>(event, "Photon").particlesByPt(Cuts::abseta < 1.37 || Cuts::abseta > 1.5);
if (photons.size() < 3) vetoEvent;
// Get jets, and corresponding jet areas
vector<vector<double> > ptDensities(ETA_BINS.size()-1);
FastJets fastjets = apply<FastJets>(event, "KtJetsD05");
const auto clust_seq_area = fastjets.clusterSeqArea();
for (const Jet& jet : fastjets.jets()) {
const double area = clust_seq_area->area(jet);
if (area < 1e-3) continue;
const int ieta = binIndex(jet.abseta(), ETA_BINS);
if (ieta != -1) ptDensities[ieta].push_back(jet.pT()/area);
}
// Compute median jet properties over the jets in the event
vector<double> ptDensity;
for (size_t b = 0; b < ETA_BINS.size()-1; ++b) {
double median = 0.0;
if (ptDensities[b].size() > 0) {
std::sort(ptDensities[b].begin(), ptDensities[b].end());
int nDens = ptDensities[b].size();
median = (nDens % 2 == 0) ? (ptDensities[b][nDens/2]+ptDensities[b][(nDens-2)/2])/2 : ptDensities[b][(nDens-1)/2];
}
ptDensity.push_back(median);
}
// Loop over photons and fill vector of isolated ones
Particles isolated_photons;
for (const Particle& photon : photons) {
if (!photon.isPrompt()) continue;
// Remove photons in ECAL crack region
const double eta_P = photon.eta();
const double phi_P = photon.phi();
// Compute isolation via particles within an R=0.4 cone of the photon
const Particles fs = apply<FinalState>(event, "FS").particles();
FourMomentum mom_in_EtCone;
for (const Particle& p : fs) {
// Reject if not in cone
if (deltaR(photon.momentum(), p.momentum()) > 0.4) continue;
// Reject if in the 5x7 cell central core
if (fabs(eta_P - p.eta()) < 0.025 * 5 * 0.5 && fabs(phi_P - p.phi()) < PI/128. * 7 * 0.5) continue;
// Sum momentum
mom_in_EtCone += p.momentum();
}
// Now figure out the correction (area*density)
const double EtCone_area = M_PI*sqr(0.4) - (7*.025)*(5*M_PI/128.); // cone area - central core rectangle
const double correction = ptDensity[binIndex(fabs(eta_P), ETA_BINS)] * EtCone_area;
// Discard the photon if there is more than 11 GeV of cone activity
// NOTE: Shouldn't need to subtract photon itself (it's in the central core)
if (mom_in_EtCone.Et() - correction > 10*GeV) continue;
// Add isolated photon to list
isolated_photons.push_back(photon);
}///loop over photons
// Require at least two isolated photons
if (isolated_photons.size() < 3) vetoEvent;
// Select leading pT pair
sortByPt(isolated_photons);
const FourMomentum y1 = isolated_photons[0];
const FourMomentum y2 = isolated_photons[1];
const FourMomentum y3 = isolated_photons[2];
// Leading photon should have pT > 40 GeV, subleading > 30 GeV
if (y1.pT() < 27*GeV) vetoEvent;
if (y2.pT() < 22*GeV) vetoEvent;
if (y3.pT() < 15*GeV) vetoEvent;
// Require the two photons to be separated (dR>0.4)
if (deltaR(y1,y2) < 0.45) vetoEvent;
if (deltaR(y1,y3) < 0.45) vetoEvent;
if (deltaR(y2,y3) < 0.45) vetoEvent;
const FourMomentum yyy = y1 + y2 + y3;
const FourMomentum y1y2 = y1 + y2;
const FourMomentum y1y3 = y1 + y3;
const FourMomentum y2y3 = y2 + y3;
const double Myyy = yyy.mass() / GeV;
const double dPhiy1y2 = mapAngle0ToPi(deltaPhi(y1, y2));
const double dPhiy1y3 = mapAngle0ToPi(deltaPhi(y1, y3));
const double dPhiy2y3 = mapAngle0ToPi(deltaPhi(y2, y3));
const double dEtay1y2 = fabs(y1.eta() - y2.eta());
const double dEtay1y3 = fabs(y1.eta() - y3.eta());
const double dEtay2y3 = fabs(y2.eta() - y3.eta());
if(Myyy < 50.) vetoEvent;
// Fill histograms
_h["etg1"]->fill(y1.pT() / GeV);
_h["etg2"]->fill(y2.pT() / GeV);
_h["etg3"]->fill(y3.pT() / GeV);
_h["dphig1g2"]->fill(dPhiy1y2);
_h["dphig1g3"]->fill(dPhiy1y3);
_h["dphig2g3"]->fill(dPhiy2y3);
_h["detag1g2"]->fill(dEtay1y2);
_h["detag1g3"]->fill(dEtay1y3);
_h["detag2g3"]->fill(dEtay2y3);
_h["mg1g2"]->fill(y1y2.mass() / GeV);
_h["mg1g3"]->fill(y1y3.mass() / GeV);
_h["mg2g3"]->fill(y2y3.mass() / GeV);
_h["mg1g2g3"]->fill(Myyy);
}
// Normalise histograms etc., after the run
void finalize() {
const double sf = crossSection() / (femtobarn * sumOfWeights());
for (auto &hist : _h) { scale(hist.second, sf); }
}
private:
map<string, Histo1DPtr> _h;
const vector<double> ETA_BINS = { 0.0, 1.5, 3.0 };
};
RIVET_DECLARE_PLUGIN(ATLAS_2017_I1644367);
}
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