Rivet analyses

// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {


  /// @brief Lambda_b at 7 TeV
  class CMS_2012_I1113442 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_I1113442);


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

    /// Book histograms and initialise projections before the run
    void init() {
      declare(UnstableParticles(), "UFS");
      // histograms
      book(_h_lam   , 1,1,1);
      book(_h_bar   , "TMP/bar_total",refData<YODA::BinnedEstimate<int> >(1,1,2));
      book(_h_pT_lam, 2,1,1);
      book(_h_pT_bar, "TMP/bar_pT"   ,refData(2,1,2));
      book(_h_y_lam , 3,1,1);
      book(_h_y_bar , "TMP/bar_y"    ,refData(3,1,2));
      for (unsigned int ix=0; ix<2; ++ix) {
        book(_c_lam[ix], "TMP/c_lam_"+toString(ix+1));
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Final state of unstable particles to get particle spectra
      const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
      for (const Particle& p : ufs.particles(Cuts::abspid==5122) ) {
        // stuff for the branching ratio
        const double sign = p.pid()/p.abspid();
        if (p.children().size()==2 &&
         ( (p.children()[0].pid()==sign*3122 && p.children()[1].pid()==443) ||
           (p.children()[1].pid()==sign*3122 && p.children()[0].pid()==443) )) {
          _c_lam[0]->fill(1.);
        }
        _c_lam[1]->fill(1.);
        const double pT = p.perp();
        const double y  = p.absrap();
        if (y>2. || pT<10.) continue;
        if (p.pid()>0) {
          _h_lam->fill(round(sqrtS()));
          _h_pT_lam->fill(pT);
          _h_y_lam ->fill(y);
        }
        else {
          _h_bar->fill(round(sqrtS()));
          _h_pT_bar->fill(pT);
          _h_y_bar ->fill(y);
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      double fact = crossSection()/nanobarn/sumOfWeights();
      // total cross sectiohn and ratio
      scale(_h_lam, fact);
      scale(_h_bar, fact);
      BinnedEstimatePtr<int> tmpI;
      book(tmpI,1,1,2);
      divide(_h_bar, _h_lam, tmpI);
      // d sig / dpT
      fact *= 1000.;
      scale(_h_pT_lam, fact);
      scale(_h_pT_bar, fact);
      Estimate1DPtr tmp;
      book(tmp, 2, 1, 2);
      divide(_h_pT_bar, _h_pT_lam, tmp);
      // d sig / dy
      scale(_h_y_lam, fact);
      scale(_h_y_bar, fact);
      book(tmp,3, 1, 2);
      divide(_h_y_bar, _h_y_lam, tmp);
      // now branching ratio for cross sections
      if (_c_lam[1]->effNumEntries()>0.) {
        scale(_h_lam   , *_c_lam[0]/ *_c_lam[1]);
        scale(_h_pT_lam, *_c_lam[0]/ *_c_lam[1]);
        scale(_h_y_lam , *_c_lam[0]/ *_c_lam[1]);
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    BinnedHistoPtr<int> _h_lam,_h_bar;
    Histo1DPtr _h_pT_lam,_h_pT_bar;
    Histo1DPtr _h_y_lam,_h_y_bar;
    CounterPtr _c_lam[2];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(CMS_2012_I1113442);

}