Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/Sphericity.hh"
#include "Rivet/Projections/Thrust.hh"

namespace Rivet {


  /// @brief event shapes at 29 GeV
  class HRS_1985_I201482 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(HRS_1985_I201482);


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

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

      // Initialise and register projections
      declare(Beam(), "Beams");
      const ChargedFinalState cfs;
      declare(cfs, "FS");
      declare(Sphericity(cfs), "Sphericity");
      const Thrust thrust(cfs);
      declare(thrust, "Thrust");

      // Book histograms
      book(_histSphericity,  1, 1, 1);
      book(_histThrust    ,  3, 1, 1);
      book(_histThrust2Jet,  4, 1, 1);
      book(_histAplanarity,  6, 1, 1);
      book(_histZ         , 10, 1, 1);
      book(_histZ2Jet     , 11, 1, 1);
      book(_histZScale    , 12, 1, 1);
      book(_histZJet[0]   , 13, 1, 1);
      book(_histZJet[1]   , 14, 1, 1);
      book(_histZJet[2]   , 15, 1, 1);
      book(_histXFeyn     , 16, 1, 1);
      book(_histXFeyn2Jet , 17, 1, 1);
      book(_histRap[0]    , 19, 1, 1);
      book(_histRap[1]    , 20, 1, 1);
      book(_histPtT       , 22, 1, 1);
      book(_histPtT2Jet   , 23, 1, 1);
      book(_histPtTIn     , 24, 1, 1);
      book(_histPtTOut    , 25, 1, 1);
      book(_wSum ,"TMP/wSum");
      book(_wSum2,"TMP/wSum2");

      _axes[0] = YODA::Axis<double>({-5.0, -4.0, -3.5, -3.0, -2.75, -2.5, -2.3, -2.0, -1.75, -1.5,
                                      -1.25, -1.0, -0.75, -0.5, -0.25, 0.0, 0.25, 0.5, 0.75, 1.0,
                                      1.25, 1.5, 1.75, 2.0, 2.3, 2.5, 2.75, 3.0, 3.5, 4.0, 5.0});
      _axes[1] = YODA::Axis<double>({-4.0, -3.5, -3.0, -2.75, -2.5, -2.25, -2.0, -1.75, -1.5,
                                     -1.25, -1.0, -0.75, -0.5, -0.25, 0.0, 0.25, 0.5, 0.75,
                                      1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75, 3.0, 3.5, 4.0});
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      if (_edges[0].empty()) {
        _edges[0] = _histRap[0]->xEdges();
        _edges[1] = _histRap[1]->xEdges();
      }
      // require 5 charged particles
      const FinalState& fs = apply<FinalState>(event, "FS");
      const size_t numParticles = fs.particles().size();
      if(numParticles<5) vetoEvent;
      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double meanBeamMom = ( beams.first.p3().mod() +
                                   beams.second.p3().mod() ) / 2.0;
      MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
      // calc thrust and sphericity
      const Thrust& thrust = apply<Thrust>(event, "Thrust");
      Vector3 axis = thrust.thrustAxis();
      const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
      // identify two and three jet regions
      bool twoJet   = sphericity.sphericity()<=0.25 && sphericity.aplanarity()<=0.1;
      //bool threeJet = sphericity.sphericity() >0.25 && sphericity.aplanarity()<=0.1;
      _wSum->fill();
      if (twoJet) _wSum2->fill();
      // basic event shapes
      _histSphericity->fill(sphericity.sphericity());
      _histThrust    ->fill(thrust.thrust());
      _histAplanarity->fill(sphericity.aplanarity());
      if(twoJet)  _histThrust2Jet->fill(thrust.thrust());
      double pTSqIn  = 0.;
      double pTSqOut = 0.;
      unsigned int iPlus(0),iMinus(0);
      // single particle  dists
      for(const Particle & p : sortBy(fs.particles(),cmpMomByP)) {
        const double z  = p.p3().mod()/meanBeamMom;
        const double momT = axis.dot(p.p3());
        const double xF = fabs(momT)/meanBeamMom;
        const double energy = p.E();
        const double rap = 0.5 * std::log((energy + momT) / (energy - momT));
        const double pTin  = dot(p.p3(), thrust.thrustMajorAxis());
        const double pTout = dot(p.p3(), thrust.thrustMinorAxis());
        const double pT2 = sqr(pTin)+sqr(pTout);
        pTSqIn  += sqr(dot(p.p3(), sphericity.sphericityMajorAxis()));
        pTSqOut += sqr(dot(p.p3(), sphericity.sphericityMinorAxis()));
        _histZ->fill(z);
        _histZScale->fill(z);
        _histXFeyn ->fill(xF, z);
        _histRap[0]->fill(map2string(rap, 0));
        _histPtT->fill(pT2);
        if(twoJet) {
          _histZ2Jet->fill(z);
          _histXFeyn2Jet->fill(xF, z);
          _histRap[1]->fill(map2string(rap, 1));
          _histPtT2Jet->fill(pT2);
          if(momT>0.&&iPlus<3) {
            _histZJet[iPlus]->fill(z);
            iPlus+=1;
          }
          else if(momT<0.&&iMinus<3) {
            _histZJet[iMinus]->fill(z);
            iMinus+=1;
          }
        }
      }
      _histPtTIn ->fill(pTSqIn /numParticles);
      _histPtTOut->fill(pTSqOut/numParticles);
    }


    /// Normalise histograms etc., after the run
    void finalize() {

      normalize(_histSphericity);
      normalize(_histThrust);
      normalize(_histThrust2Jet);
      normalize(_histAplanarity);
      scale(_histZ, 1./ *_wSum);
      scale(_histZScale,    sqr(sqrtS())*crossSection()/microbarn/sumOfWeights());
      scale(_histXFeyn,     1./M_PI/ *_wSum);
      scale(_histRap[0],    1./ *_wSum);
      scale(_histZ2Jet,     1./ *_wSum2);
      scale(_histXFeyn2Jet, 1./M_PI/ *_wSum2);
      scale(_histRap[1],    1./ *_wSum2);
      scale(_histPtT,       1./ *_wSum);
      scale(_histPtT2Jet,   1./ *_wSum2);
      scale(_histPtTIn,     1./ *_wSum);
      scale(_histPtTOut,    1./ *_wSum);
      for (size_t i=0; i<3; ++i) {
        scale(_histZJet[i], 0.5/ *_wSum2);
      }
      for(unsigned int ix=0;ix<2;++ix) {
        for(auto & b: _histRap[ix]->bins()) {
          const size_t idx = b.index();
          b.scaleW(1./_axes[ix].width(idx));
        }
      }
    }

    /// @}

    string map2string(const double value, const size_t k) const {
      const size_t idx = _axes[k].index(value);
      if (idx && idx <= _edges[k].size())  return _edges[k][idx-1];
      return "OTHER";
    }


    /// @name Histograms
    /// @{
    Histo1DPtr _histSphericity, _histThrust, _histThrust2Jet, _histAplanarity,
      _histZ, _histZ2Jet, _histZScale, _histXFeyn, _histXFeyn2Jet,
      _histPtT, _histPtT2Jet, _histPtTIn, _histPtTOut, _histZJet[3];
    BinnedHistoPtr<string> _histRap[2];
    CounterPtr _wSum,_wSum2;

    YODA::Axis<double> _axes[2];
    vector<string> _edges[2];

    /// @}


  };


  RIVET_DECLARE_PLUGIN(HRS_1985_I201482);


}