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## Rivet analyses reference

### CMS_2012_I1107658

Measurement of the underlying event activity in the Drell-Yan process at a centre-of-mass energy of 7 TeV
Experiment: CMS (LHC)
Inspire ID: 1107658
Status: VALIDATED
Authors:
• Sunil Bansal (sunil.bansal@cern.ch)
References:
• CMS-QCD-11-012
• CERN-PH-EP-2012-085
• arXiv: 1204.1411
Beams: p+ p+
Beam energies: (3500.0, 3500.0) GeV
Run details:
• Drell-Yan events with $Z/\gamma^* \to \mu\mu$. $m(\mu,\mu) > 20$ GeV

A measurement of the underlying event activity using Drell-Yan events using muonic final state. The production of charged particles with pseudorapidity $|\eta| < 2$ and transverse momentum $p_\perp > 0.5\,\text{GeV}/c$ is studied in towards, transverse and away region w.r.t. to the direction of di-muon system. The UE activity is measured in terms of of a particle density and an energy density. The particle density is computed as the average number of primary charged particles per unit pseudorapidity and per unit azimuth. The energy density is expressed in terms of the average of the scalar sum of the transverse momenta of primary charged particles per unit pseudorapidity and azimuth. The ratio of the energy and particle density is also reported in 3 regions. UE activity is studied as a function of invariant mass of muon pair ($M_{\mu\mu}$) by limiting the ISR contribution by requiring transverse momentum of muon pair $p_\perp(\mu\mu) < 5\,\text{GeV}/c$. The $p_\perp(\mu\mu)$ dependence is studied for the events having $M_{\mu\mu}$ in window of 81--101 GeV/$c$. The normalized charged particle multiplicity and $p_\perp$ spectrum of the charged particles in three regions also been reported for events having $M_{\mu\mu}$ in window of 81--101 GeV/$c$. Multiplicity and $p_\perp$ spectra in the transverse region are also reported, for events having $p_\perp(\mu\mu) < 5\,\text{GeV}/c$.

Source code: CMS_2012_I1107658.cc
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 // -*- C++ -*- #include "Rivet/Analysis.hh" #include "Rivet/Projections/FinalState.hh" #include "Rivet/Projections/ZFinder.hh" #include "Rivet/Projections/FinalState.hh" #include "Rivet/Projections/ChargedFinalState.hh" #include "Rivet/Projections/VetoedFinalState.hh" namespace Rivet { /// Underlying event activity in the Drell-Yan process at 7 TeV class CMS_2012_I1107658 : public Analysis { public: /// Constructor CMS_2012_I1107658() : Analysis("CMS_2012_I1107658") { } /// Initialization void init() { /// @note Using a bare muon Z (but with a clustering radius!?) Cut cut = Cuts::abseta < 2.4 && Cuts::pT > 20*GeV; ZFinder zfinder(FinalState(), cut, PID::MUON, 4*GeV, 140*GeV, 0.2, ZFinder::NOCLUSTER); declare(zfinder, "ZFinder"); ChargedFinalState cfs(-2, 2, 500*MeV); VetoedFinalState nonmuons(cfs); nonmuons.addVetoPairId(PID::MUON); declare(nonmuons, "nonmuons"); _h_Nchg_towards_pTmumu = bookProfile1D(1, 1, 1); _h_Nchg_transverse_pTmumu = bookProfile1D(2, 1, 1); _h_Nchg_away_pTmumu = bookProfile1D(3, 1, 1); _h_pTsum_towards_pTmumu = bookProfile1D(4, 1, 1); _h_pTsum_transverse_pTmumu = bookProfile1D(5, 1, 1); _h_pTsum_away_pTmumu = bookProfile1D(6, 1, 1); _h_avgpT_towards_pTmumu = bookProfile1D(7, 1, 1); _h_avgpT_transverse_pTmumu = bookProfile1D(8, 1, 1); _h_avgpT_away_pTmumu = bookProfile1D(9, 1, 1); _h_Nchg_towards_plus_transverse_Mmumu = bookProfile1D(10, 1, 1); _h_pTsum_towards_plus_transverse_Mmumu = bookProfile1D(11, 1, 1); _h_avgpT_towards_plus_transverse_Mmumu = bookProfile1D(12, 1, 1); _h_Nchg_towards_zmass_81_101 = bookHisto1D(13, 1, 1); _h_Nchg_transverse_zmass_81_101 = bookHisto1D(14, 1, 1); _h_Nchg_away_zmass_81_101 = bookHisto1D(15, 1, 1); _h_pT_towards_zmass_81_101 = bookHisto1D(16, 1, 1); _h_pT_transverse_zmass_81_101 = bookHisto1D(17, 1, 1); _h_pT_away_zmass_81_101 = bookHisto1D(18, 1, 1); _h_Nchg_transverse_zpt_5 = bookHisto1D(19, 1, 1); _h_pT_transverse_zpt_5 = bookHisto1D(20, 1, 1); } /// Perform the per-event analysis void analyze(const Event& event) { const double weight = event.weight(); const ZFinder& zfinder = apply(event, "ZFinder"); if (zfinder.bosons().size() != 1) vetoEvent; double Zpt = zfinder.bosons()[0].pT()/GeV; double Zphi = zfinder.bosons()[0].phi(); double Zmass = zfinder.bosons()[0].mass()/GeV; Particles particles = apply(event, "nonmuons").particles(); int nTowards = 0; int nTransverse = 0; int nAway = 0; double ptSumTowards = 0; double ptSumTransverse = 0; double ptSumAway = 0; for (const Particle& p : particles) { double dphi = fabs(deltaPhi(Zphi, p.phi())); double pT = p.pT(); if ( dphi < M_PI/3 ) { nTowards++; ptSumTowards += pT; if (Zmass > 81. && Zmass < 101.) _h_pT_towards_zmass_81_101->fill(pT, weight); } else if ( dphi < 2.*M_PI/3 ) { nTransverse++; ptSumTransverse += pT; if (Zmass > 81. && Zmass < 101.) _h_pT_transverse_zmass_81_101->fill(pT, weight); if (Zpt < 5.) _h_pT_transverse_zpt_5->fill(pT, weight); } else { nAway++; ptSumAway += pT; if (Zmass > 81. && Zmass < 101.) _h_pT_away_zmass_81_101->fill(pT, weight); } } // Loop over particles const double area = 8./3.*M_PI; if (Zmass > 81. && Zmass < 101.) { _h_Nchg_towards_pTmumu-> fill(Zpt, 1./area * nTowards, weight); _h_Nchg_transverse_pTmumu-> fill(Zpt, 1./area * nTransverse, weight); _h_Nchg_away_pTmumu-> fill(Zpt, 1./area * nAway, weight); _h_pTsum_towards_pTmumu-> fill(Zpt, 1./area * ptSumTowards, weight); _h_pTsum_transverse_pTmumu-> fill(Zpt, 1./area * ptSumTransverse, weight); _h_pTsum_away_pTmumu-> fill(Zpt, 1./area * ptSumAway, weight); if (nTowards > 0) _h_avgpT_towards_pTmumu-> fill(Zpt, ptSumTowards/nTowards, weight); if (nTransverse > 0) _h_avgpT_transverse_pTmumu-> fill(Zpt, ptSumTransverse/nTransverse, weight); if (nAway > 0) _h_avgpT_away_pTmumu-> fill(Zpt, ptSumAway/nAway, weight); _h_Nchg_towards_zmass_81_101-> fill(nTowards, weight); _h_Nchg_transverse_zmass_81_101->fill(nTransverse, weight); _h_Nchg_away_zmass_81_101-> fill(nAway, weight); } if (Zpt < 5.) { _h_Nchg_towards_plus_transverse_Mmumu->fill(Zmass, (nTowards + nTransverse)/(2.*area), weight); _h_pTsum_towards_plus_transverse_Mmumu->fill(Zmass, (ptSumTowards + ptSumTransverse)/(2.*area), weight); if ((nTowards + nTransverse) > 0) _h_avgpT_towards_plus_transverse_Mmumu->fill(Zmass, (ptSumTowards + ptSumTransverse)/(nTowards + nTransverse), weight); _h_Nchg_transverse_zpt_5->fill(nTransverse, weight); } } /// Normalise histograms etc., after the run void finalize() { scale(_h_pT_towards_zmass_81_101, safediv(1, _h_Nchg_towards_zmass_81_101->integral(), 0)); scale(_h_pT_transverse_zmass_81_101, safediv(1, _h_Nchg_transverse_zmass_81_101->integral(), 0)); scale(_h_pT_away_zmass_81_101, safediv(1, _h_Nchg_away_zmass_81_101->integral(), 0)); scale(_h_pT_transverse_zpt_5, safediv(1, _h_Nchg_transverse_zpt_5->integral(), 0)); normalize(_h_Nchg_towards_zmass_81_101); normalize(_h_Nchg_transverse_zmass_81_101); normalize(_h_Nchg_away_zmass_81_101); normalize(_h_Nchg_transverse_zpt_5); } private: /// @name Histogram objects //@{ Profile1DPtr _h_Nchg_towards_pTmumu; Profile1DPtr _h_Nchg_transverse_pTmumu; Profile1DPtr _h_Nchg_away_pTmumu; Profile1DPtr _h_pTsum_towards_pTmumu; Profile1DPtr _h_pTsum_transverse_pTmumu; Profile1DPtr _h_pTsum_away_pTmumu; Profile1DPtr _h_avgpT_towards_pTmumu; Profile1DPtr _h_avgpT_transverse_pTmumu; Profile1DPtr _h_avgpT_away_pTmumu; Profile1DPtr _h_Nchg_towards_plus_transverse_Mmumu; Profile1DPtr _h_pTsum_towards_plus_transverse_Mmumu; Profile1DPtr _h_avgpT_towards_plus_transverse_Mmumu; Histo1DPtr _h_Nchg_towards_zmass_81_101; Histo1DPtr _h_Nchg_transverse_zmass_81_101; Histo1DPtr _h_Nchg_away_zmass_81_101; Histo1DPtr _h_pT_towards_zmass_81_101; Histo1DPtr _h_pT_transverse_zmass_81_101; Histo1DPtr _h_pT_away_zmass_81_101; Histo1DPtr _h_Nchg_transverse_zpt_5; Histo1DPtr _h_pT_transverse_zpt_5; //@} }; // Hook for the plugin system DECLARE_RIVET_PLUGIN(CMS_2012_I1107658); }