Rivet analyses
title: LHCB_2016_I1454404
Measurement of forward W and Z boson production in association with jets at LHCb
Experiment: LHCB (LHC)
Inspire ID: 1454404
Status: VALIDATED
Authors: - Abbie Jane Chadwick - Stephen Farry
References: - 10.1007/JHEP05(2016)131 - arXiv: hep-ex/1605.00951 - Expt page: LHCb-PAPER-2016-011, CERN-EP-2016-092
Beams: p+ p+
Beam energies: (4000.0, 4000.0)GeV
Run details: - p+ p+ -> W/Z + jet + X
Measurements are made of forward W and Z production in association with jets in the forward region. Muons and jets are required to have transverse momentum in excess of 20 Gev, and to have a pseudorapidity between 2.0 and 4.5 for muons, and between 2.2 and 4.2 for jets. A single muon is required in the case of $W$ production, and two opposite sign muons with a combined invariant mass of between 60 and 120 GeV are required for $W$ production. The leptons and jets are required to be separated by a radius of 0.5 in ($\eta$, $\phi$) space.
Source code:LHCB_2016_I1454404.cc
```c++ // -- C++ --
include "Rivet/Analysis.hh"
include "Rivet/Projections/DileptonFinder.hh"
include "Rivet/Projections/FastJets.hh"
include "Rivet/Projections/FinalState.hh"
include "Rivet/Projections/LeptonFinder.hh"
include "Rivet/Projections/MissingMomentum.hh"
namespace Rivet {
/// @brief Measurement of forward W and Z boson production with jets in pp collisions at 8 TeV class LHCB_2016_I1454404 : public Analysis { public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2016_I1454404);
/// @name Analysis methods
/// @{
/// Book histograms and initialise projections before the run
void init() {
_mode = 0;
string mode = getOption("MODE");
if (mode == "ALL")
_mode = 0;
else if (mode == "WpJET")
_mode = 1;
else if (mode == "WmJET")
_mode = 2;
else if (mode == "ZJET")
_mode = 3;
else if (mode == "WJET")
_mode = 4;
const Cut muSel = Cuts::eta >= 2.0 && Cuts::eta <= 4.5 && Cuts::pT > 20 * GeV;
// Z boson
DileptonFinder zfinder(91.2 * GeV, 0.1, muSel && Cuts::abspid == PID::MUON,
Cuts::massIn(60 * GeV, 120 * GeV));
declare(zfinder, "DileptonFinder");
// W boson
declare("MET", MissingMomentum());
LeptonFinder mf(muSel && Cuts::abspid == PID::MUON, 0.0);
declare(mf, "Muons");
// Jet Z
FastJets jetproZ(zfinder.remainingFinalState(), JetAlg::ANTIKT, 0.5); ///< @todo No jet acceptance?
declare(jetproZ, "JetsZ");
// Jet W
VetoedFinalState nomufs; ///< @todo No jet acceptance?
nomufs.vetoFinalState(mf);
FastJets jetproW(nomufs, JetAlg::ANTIKT, 0.5);
declare(jetproW, "JetsW");
// Book histograms
if (_mode == 0 || _mode == 1 || _mode == 4) {
book(_h_wpj, 1, 1, 1);
book(_h_eta_wpj, 4, 1, 1);
book(_h_etaj_wpj, 5, 1, 1);
book(_h_ptj_wpj, 6, 1, 1);
}
if (_mode == 0 || _mode == 2 || _mode == 4) {
book(_h_wmj, 1, 1, 2);
book(_h_eta_wmj, 4, 1, 2);
book(_h_etaj_wmj, 5, 1, 2);
book(_h_ptj_wmj, 6, 1, 2);
}
if (_mode == 0 || _mode == 3) {
book(_h_zj, 1, 1, 3);
book(_h_yz_zj, 7, 1, 1);
book(_h_etaj_zj, 8, 1, 1);
book(_h_ptj_zj, 9, 1, 1);
book(_h_dphi_zj, 10, 1, 1);
}
if (_mode == 0) {
book(_h_rwz, 2, 1, 1);
book(_h_rwpz, 2, 1, 2);
book(_h_rwmz, 2, 1, 3);
}
if (_mode == 0 || _mode == 4) {
book(_h_rwpm, 2, 1, 4);
book(_h_aw, 3, 1, 1);
// this is a temporary histogram to construct rwz later
book(_h_wj, "_temp_wj", refData(1, 1, 1));
}
}
/// Perform the per-event analysis
void analyze(const Event& event) {
const Cut jetSel = Cuts::eta >= 2.2 && Cuts::eta <= 4.2 && Cuts::pT > 20 * GeV;
// Z
if (_mode == 0 || _mode == 3) {
const DileptonFinder& zfinder = apply<DileptonFinder>(event, "DileptonFinder");
if (zfinder.bosons().size() == 1) {
const Particles muon = zfinder.leptons();
const Particles Z = zfinder.bosons();
const FourMomentum Zmom = Z[0].momentum();
const Jets jetsZ = apply<FastJets>(event, "JetsZ").jetsByPt(jetSel);
const Jets cleanedJetsZ = discard(jetsZ,
[&](const Jet& j) { return any(muon, deltaRLess(j, 0.5)); });
if (cleanedJetsZ.size() > 0 && cleanedJetsZ.at(0).pT() > 20 * GeV) {
const double yZ = Zmom.rap(); //histogram 7
const double etaj = cleanedJetsZ[0].eta(); //histogram 8
const double ptj = cleanedJetsZ[0].pT() / GeV; //histogram 9
double dphi_tmp = abs(Zmom.phi() - cleanedJetsZ[0].phi());
const double dphi = dphi_tmp < Rivet::pi ? dphi_tmp : Rivet::twopi - dphi_tmp;
_h_zj->fill(sqrtS() / GeV);
_h_dphi_zj->fill(dphi);
_h_yz_zj->fill(yZ); // boson rapidity vs diff cross section
_h_etaj_zj->fill(etaj); // jet pseudorapidity vs diff cross section
_h_ptj_zj->fill(ptj); //jet transverse momentum vs diff cross section
}
}
}
// W
if (_mode == 0 || _mode == 1 || _mode == 2 || _mode == 4) {
// Identify the closest-matching l+MET to m == mW
const P4& pmiss = apply<MissingMom>(event, "MET").missingMom();
const Particles& mus = apply<LeptonFinder>(event, "Muons").particles();
const int ifound = closestMatchIndex(mus, pmiss, Kin::mass, 80.4 * GeV, 0 * GeV, 500 * GeV);
if (ifound >= 0) {
const Particle& mu = mus[ifound];
const Jets jetsW = apply<FastJets>(event, "JetsW").jetsByPt(jetSel);
const Jets cleanedJetsW = discard(jetsW, deltaRLess(mu, 0.5));
if (cleanedJetsW.size() > 0 && cleanedJetsW.at(0).pT() > 20 * GeV) {
const double etaj = cleanedJetsW[0].eta(); //histogram 5
const double etamu = mu.eta(); //histogram 4
if ((_mode == 0 || _mode == 1 || _mode == 4) && mu.charge() > 0) {
//fill with W related analysis
if (_mode != 1) _h_wj->fill(sqrtS() / GeV); // don't need this for single charge case
_h_wpj->fill(sqrtS() / GeV);
_h_eta_wpj->fill(etamu); // W+ Jet muon pseudorapidity vs diff cross section
_h_etaj_wpj->fill(etaj); // W+ Jet jet pseudorapidity vs diff cross section
_h_ptj_wpj->fill(cleanedJetsW[0].pT()
/ GeV); // W+ Jet jet transverse momentum vs diff cross section
}
else if ((_mode == 0 || _mode == 2 || _mode == 4) && mu.charge() < 0) {
//fill with W related analysis
if (_mode != 2) _h_wj->fill(sqrtS() / GeV);
_h_wmj->fill(sqrtS() / GeV); // don't need this for single charge case
_h_eta_wmj->fill(etamu); // W- Jet muon pseudorapidity vs diff cross section
_h_etaj_wmj->fill(etaj); // W- Jet jet pseudorapidity vs diff cross section
_h_ptj_wmj->fill(cleanedJetsW[0].pT()
/ GeV); // W+ Jet jet transverse momentum vs diff cross section
}
}
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
const double scalefactor = crossSection() / picobarn / sumOfWeights();
if (_mode == 0 || _mode == 1 || _mode == 4) {
scale({_h_wpj, _h_eta_wpj, _h_etaj_wpj, _h_ptj_wpj}, scalefactor);
}
if (_mode == 0 || _mode == 2 || _mode == 4) {
scale({_h_wmj, _h_eta_wmj, _h_etaj_wmj, _h_ptj_wmj}, scalefactor);
}
if (_mode == 0 || _mode == 3) {
scale({_h_zj, _h_yz_zj, _h_etaj_zj, _h_ptj_zj, _h_dphi_zj}, scalefactor);
}
if (_mode == 0) {
scale(_h_wj, scalefactor); // need to scale this for consistency
divide(_h_wpj, _h_zj, _h_rwpz);
divide(_h_wmj, _h_zj, _h_rwmz);
divide(_h_wj, _h_zj, _h_rwz);
}
if (_mode == 0 || _mode == 4) {
divide(_h_wpj, _h_wmj, _h_rwpm);
asymm(_h_wpj, _h_wmj, _h_aw);
}
}
protected:
size_t _mode;
/// @name Histograms
/// @{
Histo1DPtr _h_wpj, _h_wmj, _h_wj, _h_zj;
Estimate1DPtr _h_rwz, _h_rwpz, _h_rwmz, _h_rwpm, _h_aw;
Histo1DPtr _h_eta_wpj, _h_eta_wmj, _h_etaj_wpj, _h_etaj_wmj, _h_ptj_wpj, _h_ptj_wmj;
Histo1DPtr _h_yz_zj, _h_etaj_zj, _h_ptj_zj, _h_dphi_zj;
/// @}
};
RIVET_DECLARE_PLUGIN(LHCB_2016_I1454404);
} ```