Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/LeptonFinder.hh"
#include "Rivet/Projections/MissingMomentum.hh"

namespace Rivet {


  /// @brief MC validation analysis for W polarisation
  class MC_WPOL : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(MC_WPOL);


    /// @name Analysis methods
    /// @{

    /// Book histograms and initialise projections before the run
    void init() {

      declare(MissingMomentum(), "MET");

      LeptonFinder lf(0.1, Cuts::abspid == PID::ELECTRON);
      declare(lf, "Leptons");

      Beam beams;
      declare(beams, "Beams");

      vector<string> tags{"_wplus", "_wminus"};
      _h_dists.resize(tags.size());
      _h_histos.resize(tags.size());
      for (size_t i = 0; i < tags.size(); ++i) {
        _h_dists[i].resize(11, Profile1DPtr());
        double sqrts = sqrtS() > 0. ? sqrtS() : 14000.;
        book(_h_dists[i][0], "A0" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][1], "A1" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][2], "A2" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][3], "A3" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][4], "A4" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][5], "A5" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][6], "A6" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][7], "A7" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][8], "fL" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][9], "fR" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        book(_h_dists[i][10], "f0" + tags[i], logspace(100, 1.0, 0.5 * sqrts));
        _h_histos[i].resize(4, Histo1DPtr());
        book(_h_histos[i][0], "thetastar" + tags[i], 100, -1.0, 1.0);
        book(_h_histos[i][1], "phistar" + tags[i], 90, 0.0, 360.0);
        book(_h_histos[i][2], "thetastar_ptw20" + tags[i], 100, -1.0, 1.0);
        book(_h_histos[i][3], "phistar_ptw20" + tags[i], 90, 0.0, 360.0);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {

      // MET cut
      const P4& pmiss = apply<MissingMom>(event, "MET").missingMom();
      if (pmiss.pT() < 25 * GeV) vetoEvent;

      // Identify the closest-matching l+MET to m == mW
      const Particles& ls = apply<LeptonFinder>(event, "Leptons").particles();
      const int ifound = closestMassIndex(ls, pmiss, 80.4 * GeV, 60 * GeV, 100 * GeV);
      if (ifound < 0) vetoEvent;

      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      FourMomentum pb1(beams.second.momentum()), pb2(beams.first.momentum());
      const Particle& lepton = ls[ifound];
      FourMomentum pl(lepton.momentum());
      const size_t idx = lepton.charge3() > 0 ? 0 : 1;
      const FourMomentum plnu = lepton.mom() + pmiss;

      const LorentzTransform cms = LorentzTransform::mkFrameTransformFromBeta(plnu.betaVec());
      Matrix3 zrot(plnu.p3(), Vector3(0.0, 0.0, 1.0));
      pl = cms.transform(pl);
      pb1 = cms.transform(pb1);
      pb2 = cms.transform(pb2);
      Vector3 pl3 = pl.p3();
      Vector3 pb13 = pb1.p3();
      Vector3 pb23 = pb2.p3();
      pl3 = zrot * pl3;
      pb13 = zrot * pb13;
      pb23 = zrot * pb23;
      Vector3 xref(cos(pb13.theta()) > cos(pb23.theta()) ? pb13 : pb23);
      Matrix3 xrot(Vector3(xref.x(), xref.y(), 0.0), Vector3(1.0, 0.0, 0.0));
      pl3 = xrot * pl3;

      double ptw(plnu.pT() / GeV);
      double thetas(pl3.theta()), phis(pl3.phi());
      double costhetas(cos(thetas)), sinthetas(sin(thetas));
      double cosphis(cos(phis)), sinphis(sin(phis));
      if (phis < 0.0) phis += 2.0 * M_PI;

      _h_histos[idx][0]->fill(costhetas);
      _h_histos[idx][1]->fill(phis * 180.0 / M_PI);
      if (ptw > 20.0) {
        _h_histos[idx][2]->fill(costhetas);
        _h_histos[idx][3]->fill(phis * 180.0 / M_PI);
      }
      _h_dists[idx][0]->fill(ptw, 10.0 / 3.0 * (1.0 - 3.0 * sqr(costhetas)) + 2.0 / 3.0);
      _h_dists[idx][1]->fill(ptw, 10.0 * sinthetas * costhetas * cosphis);
      _h_dists[idx][2]->fill(ptw, 10.0 * sqr(sinthetas) * (sqr(cosphis) - sqr(sinphis)));
      _h_dists[idx][3]->fill(ptw, 4.0 * sinthetas * cosphis);
      _h_dists[idx][4]->fill(ptw, 4.0 * costhetas);
      _h_dists[idx][5]->fill(ptw, 4.0 * sinthetas * sinphis);
      _h_dists[idx][6]->fill(ptw, 10.0 * costhetas * sinthetas * sinphis);
      _h_dists[idx][7]->fill(ptw, 10.0 * sqr(sinthetas) * cosphis * sinphis);
      _h_dists[idx][8]->fill(ptw, 0.5 * sqr(1.0 - costhetas) - (1.0 - 2.0 * sqr(costhetas)));
      _h_dists[idx][9]->fill(ptw, 0.5 * sqr(1.0 + costhetas) - (1.0 - 2.0 * sqr(costhetas)));
      _h_dists[idx][10]->fill(ptw, 5.0 * sqr(sinthetas) - 3.0);
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (size_t i = 0; i < _h_histos.size(); ++i) {
        for (Histo1DPtr histo : _h_histos[i]) {
          scale(histo, crossSection() / picobarn / sumOfWeights());
        }
      }
    }

    /// @}


  private:

    /// @name Histograms
    /// @{
    vector<vector<Profile1DPtr>> _h_dists;
    vector<vector<Histo1DPtr>> _h_histos;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(MC_WPOL);

}