1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/FinalState.hh"
  4#include "Rivet/Projections/MissingMomentum.hh"
  5#include "Rivet/Projections/LeptonFinder.hh"
  6#include "Rivet/Projections/LeadingParticlesFinalState.hh"
  7#include "Rivet/Projections/IdentifiedFinalState.hh"
  8
  9namespace Rivet {
 10
 11
 12  /// @brief D0 Run II measurement of W charge asymmetry
 13  ///
 14  /// @author Andy Buckley
 15  /// @author Gavin Hesketh
 16  class D0_2008_I791230 : public Analysis {
 17  public:
 18
 19    RIVET_DEFAULT_ANALYSIS_CTOR(D0_2008_I791230);
 20
 21
 22    /// @name Analysis methods
 23    /// @{
 24
 25    // Book histograms and set up projections
 26    void init() {
 27
 28      // Projections
 29      declare("MET", MissingMomentum());
 30      LeptonFinder ef(0.2, Cuts::abseta < 5 && Cuts::pT > 25*GeV && Cuts::abspid == PID::ELECTRON);
 31      declare(ef, "Elecs");
 32
 33      // Histograms (temporary +- charge histos and scatters to store the calculated asymmetries)
 34      for (size_t pmindex = 0; pmindex < 2; ++pmindex) {
 35        const string suffix = (pmindex == 0) ? "plus" : "minus";
 36        book(_hs_dsigpm_deta_25_35[pmindex] ,"TMP/dsigpm_deta_25_35_" + suffix, refData(1, 1, 1));
 37        book(_hs_dsigpm_deta_35[pmindex] ,"TMP/dsigpm_deta_35_" + suffix, refData(1, 1, 2));
 38        book(_hs_dsigpm_deta_25[pmindex] ,"TMP/dsigpm_deta_25_" + suffix, refData(1, 1, 3));
 39      }
 40      book(_h_asym1, 1, 1, 1);
 41      book(_h_asym2, 1, 1, 2);
 42      book(_h_asym3, 1, 1, 3);
 43    }
 44
 45
 46    /// Do the analysis
 47    void analyze(const Event & event) {
 48
 49      // W reco, starting with MET
 50      const P4& pmiss = apply<MissingMom>(event, "MET").missingMom();
 51      if (pmiss.pT() < 25*GeV) vetoEvent;
 52
 53      // Identify the closest-matching l+MET to m == mW
 54      const Particles& es = apply<LeptonFinder>(event, "Elecs").particles();
 55      const int ifound = closestMatchIndex(es, pmiss, Kin::mass, 80.4*GeV, 60*GeV, 100*GeV);
 56      if (ifound < 0) {
 57        MSG_DEBUG("No W candidates found: vetoing");
 58        vetoEvent;
 59      }
 60
 61      // Get the e+- momentum, and an effective charge including the eta sign
 62      const Particle& e = es[ifound];
 63      const int chg_e = sign(e.eta()) * sign(e.charge());
 64      assert(chg_e == 1 || chg_e == -1);
 65      MSG_TRACE("Charged lepton sign = " << chg_e);
 66
 67      // Fill histos with appropriate +- indexing
 68      const size_t pmindex = (chg_e > 0) ? 0 : 1;
 69      if (e.Et() < 35*GeV) _hs_dsigpm_deta_25_35[pmindex]->fill(e.abseta());
 70      else _hs_dsigpm_deta_35[pmindex]->fill(e.abseta());
 71      _hs_dsigpm_deta_25[pmindex]->fill(e.abseta());
 72    }
 73
 74
 75    /// @brief Finalize
 76    ///
 77    /// Construct asymmetry: (dsig+/deta - dsig-/deta) / (dsig+/deta + dsig-/deta) for each ET region
 78    void finalize() {
 79      asymm(_hs_dsigpm_deta_25_35[0], _hs_dsigpm_deta_25_35[1], _h_asym1);
 80      asymm(_hs_dsigpm_deta_35[0],    _hs_dsigpm_deta_35[1],    _h_asym2);
 81      asymm(_hs_dsigpm_deta_25[0],    _hs_dsigpm_deta_25[1],    _h_asym3);
 82      _h_asym1->scale(100.);
 83      _h_asym2->scale(100.);
 84      _h_asym3->scale(100.);
 85    }
 86
 87    /// @}
 88
 89
 90  private:
 91
 92    /// @name Histograms
 93    /// @{
 94    Histo1DPtr _hs_dsigpm_deta_25_35[2], _hs_dsigpm_deta_35[2], _hs_dsigpm_deta_25[2];
 95    Estimate1DPtr _h_asym1, _h_asym2, _h_asym3;
 96    /// @}
 97
 98  };
 99
100
101  RIVET_DECLARE_ALIASED_PLUGIN(D0_2008_I791230, D0_2008_S7837160);
102
103}