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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
namespace Rivet {
/// CMS 4-jet production at 7 TeV
class CMS_2013_I1273574 : public Analysis {
public:
/// Constructor
CMS_2013_I1273574()
: Analysis("CMS_2013_I1273574")
{ }
/// Book histograms and initialise projections before the run
void init() {
const FinalState cnfs((Cuts::etaIn(-4.7, 4.7)));
declare(FastJets(cnfs, FastJets::ANTIKT, 0.5), "Jets");
// Modified to match the HEPDATA record.
// eta of highest pT jet
//book(_h_jetetas[0] ,1,1,1);
book(_h_jetetas[0] ,6,1,1);
// pt of the highest pT jet
book(_h_jetpts[0] ,2,1,1);
//book(_h_DeltaS ,3,1,1);
book(_h_DeltaS ,12,1,1);
//book(_h_DeltaPhiSoft ,4,1,1);
book(_h_DeltaPhiSoft ,10,1,1);
//book(_h_DeltaPtRelSoft ,5,1,1);
book(_h_DeltaPtRelSoft ,11,1,1);
// eta and pT of 3rd highest pT jet
//book(_h_jetetas[2] ,6,1,1);
//book(_h_jetpts[2] ,7,1,1);
book(_h_jetetas[2] ,8,1,1);
book(_h_jetpts[2] ,4,1,1);
// eta and pT of 4th highest pT jet
//book(_h_jetetas[3] ,8,1,1);
//book(_h_jetpts[3] ,9,1,1);
book(_h_jetetas[3] ,9,1,1);
book(_h_jetpts[3] ,5,1,1);
// eta and pT of 2nd highest pT jet
//book(_h_jetetas[1] ,10,1,1);
//book(_h_jetpts[1] ,11,1,1);
book(_h_jetetas[1] ,7,1,1);
book(_h_jetpts[1] ,3,1,1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
/// @todo Use jetsByPt(ptGtr(20*GeV) & absetaIn(4.7)), then no need for the lower loop;
const Jets jets = apply<FastJets>(event, "Jets").jetsByPt(20*GeV);
if (jets.size() < 4) vetoEvent;
// Ensure that there are exactly 4 jets > 20 GeV, with two above 50 GeV
Jets hardjets, alljets;
for (const Jet& j : jets) {
if (j.abseta() > 4.7) continue;
if (j.pT() > 50*GeV) hardjets.push_back(j);
if (j.pT() > 20*GeV) alljets.push_back(j);
}
if (hardjets.size() < 2 || alljets.size() != 4) vetoEvent;
const double weight = 1.0;
// Histogram pT and eta of all 4 jets
for (size_t i = 0; i < 4; ++i) {
_h_jetpts[i]->fill(alljets[i].pT()/GeV, weight);
_h_jetetas[i]->fill(alljets[i].eta(), weight);
}
// Create vector sums of the hard and soft pairs of jets
const FourMomentum p12 = alljets[0].momentum() + alljets[1].momentum();
const FourMomentum p34 = alljets[2].momentum() + alljets[3].momentum();
// Fill the delta(phi) between the soft jets
const double dphisoft = deltaPhi(alljets[2], alljets[3]);
_h_DeltaPhiSoft->fill(dphisoft, weight);
// Fill the pT balance between the soft jets
const double ptbalanceSoft = p34.pT() / (alljets[2].pT() + alljets[3].pT());
_h_DeltaPtRelSoft->fill(ptbalanceSoft, weight);
// Fill the azimuthal angle difference between the two jet pairs
const double p12p34_trans = p12.px()*p34.px() + p12.py()*p34.py();
const double DeltaS = acos( p12p34_trans / p12.pT() / p34.pT() );
_h_DeltaS->fill(DeltaS, weight);
}
/// Normalise histograms (mostly to cross-section)
void finalize() {
const double invlumi = crossSection()/picobarn/sumOfWeights();
for (size_t i = 0; i < 4; ++i) {
scale(_h_jetpts[i], invlumi);
scale(_h_jetetas[i], invlumi);
}
normalize(_h_DeltaPtRelSoft);
normalize(_h_DeltaPhiSoft);
normalize(_h_DeltaS);
}
private:
Histo1DPtr _h_jetpts[4], _h_jetetas[4];
Histo1DPtr _h_DeltaS, _h_DeltaPhiSoft, _h_DeltaPtRelSoft;
};
RIVET_DECLARE_PLUGIN(CMS_2013_I1273574);
}
|