Rivet analyses
Measurement of multi-jet cross sections
Experiment: ATLAS (LHC)
Inspire ID: 917599
Status: VALIDATED
Authors: - Frank Siegert
References: - Expt page: ATLAS-STDM-2010-12 - arXiv: 1107.2092
Beams: p+ p+
Beam energies: (3500.0, 3500.0)GeV
Run details: - Pure QCD, inclusive enough for jet pT down to 60 GeV.
Inclusive multi-jet production is studied using an integrated luminosity of 2.4 pb-1. Results on multi-jet cross sections are presented differential in pT of the four leading jets, HT. Additionally three-to-two jet fractions are presented differential in different observables. Jets are anti-kt with R = 0.4 and R = 0.6, p⟂ > 80(60) GeV and |η| < 2.8.
Source
code:ATLAS_2011_I917599.cc
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/FastJets.hh"
namespace Rivet {
/// Measurement of multi-jet cross sections
class ATLAS_2011_I917599 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2011_I917599);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
// Projections
const FinalState fs;
FastJets j4(fs, JetAlg::ANTIKT, 0.4);
j4.useInvisibles();
declare(j4, "AntiKtJets04");
FastJets j6(fs, JetAlg::ANTIKT, 0.6);
j6.useInvisibles();
declare(j6, "AntiKtJets06");
// Persistent histograms
book(_h_jet_multi_inclusive, 1, 1, 1);
book(_h_jet_multi_ratio, 2, 1, 1);
_h_jet_pT.resize(4);
book(_h_jet_pT[0] ,3, 1, 1);
book(_h_jet_pT[1] ,4, 1, 1);
book(_h_jet_pT[2] ,5, 1, 1);
book(_h_jet_pT[3] ,6, 1, 1);
book(_h_HT_2 ,7, 1, 1);
book(_h_HT_3 ,8, 1, 1);
book(_h_HT_4 ,9, 1, 1);
//
book(_h_pTlead_R06_60_ratio, 10, 1, 1);
book(_h_pTlead_R06_80_ratio, 11, 1, 1);
book(_h_pTlead_R06_110_ratio, 12, 1, 1);
book(_h_pTlead_R04_60_ratio, 13, 1, 1);
book(_h_pTlead_R04_80_ratio, 14, 1, 1);
book(_h_pTlead_R04_110_ratio, 15, 1, 1);
book(_h_HT2_R06_ratio, 16, 1, 1);
book(_h_HT2_R04_ratio, 17, 1, 1);
// Temporary histograms to be divided for the dsigma3/dsigma2 ratios
book(_h_tmp_pTlead_R06_60_2 , "_pTlead_R06_60_2", refData(10, 1, 1));
book(_h_tmp_pTlead_R06_80_2 , "_pTlead_R06_80_2", refData(11, 1, 1));
book(_h_tmp_pTlead_R06_110_2, "_pTlead_R06_110_2", refData(12, 1, 1));
book(_h_tmp_pTlead_R06_60_3 , "_pTlead_R06_60_3", refData(10, 1, 1));
book(_h_tmp_pTlead_R06_80_3 , "_pTlead_R06_80_3", refData(11, 1, 1));
book(_h_tmp_pTlead_R06_110_3, "_pTlead_R06_110_3", refData(12, 1, 1));
//
book(_h_tmp_pTlead_R04_60_2 , "_pTlead_R04_60_2", refData(13, 1, 1));
book(_h_tmp_pTlead_R04_80_2 , "_pTlead_R04_80_2", refData(14, 1, 1));
book(_h_tmp_pTlead_R04_110_2, "_pTlead_R04_110_2", refData(15, 1, 1));
book(_h_tmp_pTlead_R04_60_3 , "_pTlead_R04_60_3", refData(13, 1, 1));
book(_h_tmp_pTlead_R04_80_3 , "_pTlead_R04_80_3", refData(14, 1, 1));
book(_h_tmp_pTlead_R04_110_3, "_pTlead_R04_110_3", refData(15, 1, 1));
//
book(_h_tmp_HT2_R06_2, "_HT2_R06_2", refData(16, 1, 1));
book(_h_tmp_HT2_R06_3, "_HT2_R06_3", refData(16, 1, 1));
book(_h_tmp_HT2_R04_2, "_HT2_R04_2", refData(17, 1, 1));
book(_h_tmp_HT2_R04_3, "_HT2_R04_3", refData(17, 1, 1));
}
/// Perform the per-event analysis
void analyze(const Event& event) {
if (_sedges.empty()) _sedges = _h_jet_multi_inclusive->xEdges();
vector<FourMomentum> jets04;
for (const Jet& jet : apply<FastJets>(event, "AntiKtJets04").jetsByPt(Cuts::pT > 60*GeV && Cuts::abseta < 2.8)) {
jets04.push_back(jet.momentum());
}
if (jets04.size() > 1 && jets04[0].pT() > 80.0*GeV) {
for (size_t i = 2; i <= jets04.size(); ++i) {
_h_jet_multi_inclusive->fill(discEdge(i));
}
double HT = 0.0;
for (size_t i = 0; i < jets04.size(); ++i) {
if (i < _h_jet_pT.size()) _h_jet_pT[i]->fill(jets04[i].pT());
HT += jets04[i].pT();
}
if (jets04.size() >= 2) _h_HT_2->fill(HT);
if (jets04.size() >= 3) _h_HT_3->fill(HT);
if (jets04.size() >= 4) _h_HT_4->fill(HT);
double pT1(jets04[0].pT()), pT2(jets04[1].pT());
double HT2 = pT1 + pT2;
if (jets04.size() >= 2) {
_h_tmp_HT2_R04_2->fill(HT2);
_h_tmp_pTlead_R04_60_2->fill(pT1);
if (pT2 > 80.0*GeV) _h_tmp_pTlead_R04_80_2->fill(pT1);
if (pT2 > 110.0*GeV) _h_tmp_pTlead_R04_110_2->fill(pT1);
}
if (jets04.size() >= 3) {
double pT3(jets04[2].pT());
_h_tmp_HT2_R04_3->fill(HT2);
_h_tmp_pTlead_R04_60_3->fill(pT1);
if (pT3 > 80.0*GeV) _h_tmp_pTlead_R04_80_3->fill(pT1);
if (pT3 > 110.0*GeV) _h_tmp_pTlead_R04_110_3->fill(pT1);
}
}
/// @todo It'd be better to avoid duplicating 95% of the code!
vector<FourMomentum> jets06;
for (const Jet& jet : apply<FastJets>(event, "AntiKtJets06").jetsByPt(Cuts::pT > 60*GeV && Cuts::abseta < 2.8)) {
jets06.push_back(jet.momentum());
}
if (jets06.size() > 1 && jets06[0].pT() > 80.0*GeV) {
double pT1(jets06[0].pT()), pT2(jets06[1].pT());
double HT2 = pT1 + pT2;
if (jets06.size() >= 2) {
_h_tmp_HT2_R06_2->fill(HT2);
_h_tmp_pTlead_R06_60_2->fill(pT1);
if (pT2 > 80.0*GeV) _h_tmp_pTlead_R06_80_2->fill(pT1);
if (pT2 > 110.0*GeV) _h_tmp_pTlead_R06_110_2->fill(pT1);
}
if (jets06.size() >= 3) {
double pT3(jets06[2].pT());
_h_tmp_HT2_R06_3->fill(HT2);
_h_tmp_pTlead_R06_60_3->fill(pT1);
if (pT3 > 80.0*GeV) _h_tmp_pTlead_R06_80_3->fill(pT1);
if (pT3 > 110.0*GeV) _h_tmp_pTlead_R06_110_3->fill(pT1);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
// Normalize std histos
scale(_h_jet_multi_inclusive, crossSectionPerEvent());
scale(_h_jet_pT[0], crossSectionPerEvent());
scale(_h_jet_pT[1], crossSectionPerEvent());
scale(_h_jet_pT[2], crossSectionPerEvent());
scale(_h_jet_pT[3], crossSectionPerEvent());
scale(_h_HT_2, crossSectionPerEvent());
scale(_h_HT_3, crossSectionPerEvent());
scale(_h_HT_4, crossSectionPerEvent());
scale(_h_tmp_pTlead_R06_60_2 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R06_80_2 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R06_110_2, crossSectionPerEvent());
scale(_h_tmp_pTlead_R06_60_3 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R06_80_3 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R06_110_3, crossSectionPerEvent());
scale(_h_tmp_pTlead_R04_60_2 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R04_80_2 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R04_110_2, crossSectionPerEvent());
scale(_h_tmp_pTlead_R04_60_3 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R04_80_3 , crossSectionPerEvent());
scale(_h_tmp_pTlead_R04_110_3, crossSectionPerEvent());
scale(_h_tmp_HT2_R06_2, crossSectionPerEvent());
scale(_h_tmp_HT2_R06_3, crossSectionPerEvent());
scale(_h_tmp_HT2_R04_2, crossSectionPerEvent());
scale(_h_tmp_HT2_R04_3, crossSectionPerEvent());
// Fill inclusive jet multiplicity ratio
for (auto& b : _h_jet_multi_ratio->bins()) {
size_t idx = b.index();
if (_h_jet_multi_inclusive->bin(idx).sumW()) {
const double val = _h_jet_multi_inclusive->bin(idx+1).sumW() / _h_jet_multi_inclusive->bin(idx).sumW();
// @todo Shouldn't these be added in quadrature??
const double err = ( _h_jet_multi_inclusive->bin(idx+1).relErrW() + _h_jet_multi_inclusive->bin(idx).relErrW() ) * val;
b.set(val, err);
}
}
/// Create ratio histograms
divide(_h_tmp_pTlead_R06_60_3,_h_tmp_pTlead_R06_60_2, _h_pTlead_R06_60_ratio);
divide(_h_tmp_pTlead_R06_80_3,_h_tmp_pTlead_R06_80_2, _h_pTlead_R06_80_ratio);
divide(_h_tmp_pTlead_R06_110_3,_h_tmp_pTlead_R06_110_2, _h_pTlead_R06_110_ratio);
divide(_h_tmp_pTlead_R04_60_3,_h_tmp_pTlead_R04_60_2, _h_pTlead_R04_60_ratio);
divide(_h_tmp_pTlead_R04_80_3,_h_tmp_pTlead_R04_80_2, _h_pTlead_R04_80_ratio);
divide(_h_tmp_pTlead_R04_110_3,_h_tmp_pTlead_R04_110_2, _h_pTlead_R04_110_ratio);
divide(_h_tmp_HT2_R06_3,_h_tmp_HT2_R06_2, _h_HT2_R06_ratio);
divide(_h_tmp_HT2_R04_3,_h_tmp_HT2_R04_2, _h_HT2_R04_ratio);
}
string discEdge(size_t m) const {
size_t idx = m - 2;
if (idx < _sedges.size()) return _sedges[idx];
return "OTHER";
}
/// @}
private:
/// @name Histograms
/// @{
BinnedHistoPtr<string> _h_jet_multi_inclusive;
BinnedEstimatePtr<string> _h_jet_multi_ratio;
vector<string> _sedges;
vector<Histo1DPtr> _h_jet_pT;
Histo1DPtr _h_HT_2;
Histo1DPtr _h_HT_3;
Histo1DPtr _h_HT_4;
/// @}
/// @name Ratio histograms
/// @{
Estimate1DPtr _h_pTlead_R06_60_ratio, _h_pTlead_R06_80_ratio, _h_pTlead_R06_110_ratio;
Estimate1DPtr _h_pTlead_R04_60_ratio, _h_pTlead_R04_80_ratio, _h_pTlead_R04_110_ratio;
Estimate1DPtr _h_HT2_R06_ratio, _h_HT2_R04_ratio;
/// @}
/// @name Temporary histograms to be divided for the dsigma3/dsigma2 ratios
/// @{
Histo1DPtr _h_tmp_pTlead_R06_60_2, _h_tmp_pTlead_R06_80_2, _h_tmp_pTlead_R06_110_2;
Histo1DPtr _h_tmp_pTlead_R06_60_3, _h_tmp_pTlead_R06_80_3, _h_tmp_pTlead_R06_110_3;
Histo1DPtr _h_tmp_pTlead_R04_60_2, _h_tmp_pTlead_R04_80_2, _h_tmp_pTlead_R04_110_2;
Histo1DPtr _h_tmp_pTlead_R04_60_3, _h_tmp_pTlead_R04_80_3, _h_tmp_pTlead_R04_110_3;
Histo1DPtr _h_tmp_HT2_R06_2, _h_tmp_HT2_R06_3, _h_tmp_HT2_R04_2, _h_tmp_HT2_R04_3;
/// @}
};
RIVET_DECLARE_ALIASED_PLUGIN(ATLAS_2011_I917599, ATLAS_2011_S9128077);
}Aliases: - ATLAS_2011_S9128077