Rivet analyses

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

namespace Rivet {


  /// @brief B -> K l+ l-
  class BELLE_2021_I1748231 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2021_I1748231);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid==511 or
                        Cuts::abspid==521);
      declare(ufs, "UFS");
      DecayedParticles BB(ufs);
      BB.addStable(   443);
      BB.addStable(100443);
      BB.addStable(PID::K0S);
      declare(BB, "BB");
      for(unsigned int ix=0;ix<4;++ix)
    for(unsigned int iy=0;iy<3;++iy) {
      book(_h_br[ix][iy],1,1+ix,1+iy);
      book(_h_brB[ix][iy],"TMP/h_br_"+toString(ix)+"_"+toString(iy),refData(1,1+ix,1+iy));
    }
      for(unsigned int ix=0;ix<2;++ix)
    book(_c[ix],"TMP/nB_"+toString(ix+1));
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode1   = { { 321,1},{ 13,1}, {-13,1}};
      static const map<PdgId,unsigned int> & mode1CC = { {-321,1},{ 13,1}, {-13,1}};
      static const map<PdgId,unsigned int> & mode2   = { { 310,1},{ 13,1}, {-13,1}};
      static const map<PdgId,unsigned int> & mode3   = { { 321,1},{ 11,1}, {-11,1}};
      static const map<PdgId,unsigned int> & mode3CC = { {-321,1},{ 11,1}, {-11,1}};
      static const map<PdgId,unsigned int> & mode4   = { { 310,1},{ 11,1}, {-11,1}};
      DecayedParticles BB = apply<DecayedParticles>(event, "BB");
      // loop over particles
      for(unsigned int ix=0;ix<BB.decaying().size();++ix) {
    if(BB.decaying()[ix].abspid()==521) _c[0]->fill();
    else                                _c[1]->fill();
    int imode=0;
        if ((BB.decaying()[ix].pid()>0 && BB.modeMatches(ix,3,mode1)) ||
        (BB.decaying()[ix].pid()<0 && BB.modeMatches(ix,3,mode1CC)))      imode=0;
        else if (BB.modeMatches(ix,3,mode2))                                  imode=1;
    else if ((BB.decaying()[ix].pid()>0 && BB.modeMatches(ix,3,mode3)) ||
         (BB.decaying()[ix].pid()<0 && BB.modeMatches(ix,3,mode3CC))) imode=2;
        else if (BB.modeMatches(ix,3,mode4))                                  imode=3;
        else continue;
    int il = imode<2 ? 13 : 11;
    const Particle & lp = BB.decayProducts()[ix].at(-il)[0];
    const Particle & lm = BB.decayProducts()[ix].at( il)[0];
    double qq = (lp.momentum()+lm.momentum()).mass2();
    for(unsigned int iy=0;iy<3;++iy) {
      _h_br[imode][iy]->fill(qq);
      _h_brB[imode][iy]->fill(qq);
    }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // ratio of lifetimes
      double rLife = 1.078;
      // normalize BR plots
      for(unsigned int ix=0;ix<4;++ix) {
    for(unsigned int iy=0;iy<3;++iy) {
      if(ix%2==0) {
         scale(_h_br [ix][iy],1e7/ *_c[0]);
         scale(_h_brB[ix][iy],1e7/ *_c[0]);
      }
      else {
         scale(_h_br [ix][iy],1e7      / *_c[1]);
         // KL0 modes 2x needed for isospin stuff
         scale(_h_brB[ix][iy],2e7*rLife/ *_c[1]);
      }
    }
      }
      // RK and asymmetry plots
      for(unsigned int ix=0;ix<3;++ix) {
    Estimate1DPtr RK;
    book(RK,3,1,1+ix);
    divide(_h_brB[0][ix],_h_brB[2][ix],RK);
    book(RK,3,2,1+ix);
    divide(_h_brB[1][ix],_h_brB[3][ix],RK);
    book(RK,3,3,1+ix);
    for (size_t ibin=1; ibin<_h_brB[1][ix]->numBins()+1; ++ibin) {
      double num     = _h_brB[0][ix]->bin(ibin).sumW()   +_h_brB[1][ix]->bin(ibin).sumW();
      double numErr2 = _h_brB[0][ix]->bin(ibin).sumW2()  +_h_brB[1][ix]->bin(ibin).sumW2();
      double den     = _h_brB[2][ix]->bin(ibin).sumW()   +_h_brB[3][ix]->bin(ibin).sumW();
      double denErr2 = _h_brB[2][ix]->bin(ibin).sumW2()  +_h_brB[3][ix]->bin(ibin).sumW2();
      double val(0.),err(0.);
      if(num>0. && den>0.) {
        val = num/den;
        err = val*(numErr2/sqr(num)+denErr2/sqr(den));
      }
      RK->bin(ibin).set(val, err);
    }
    book(RK,2,1,1+ix);
    asymm(_h_brB[1][ix],_h_brB[0][ix],RK);
    book(RK,2,2,1+ix);
    asymm(_h_brB[3][ix],_h_brB[2][ix],RK);
    // average plot
    book(RK,2,3,1+ix);
    for(unsigned int ibin=1; ibin<_h_brB[1][ix]->numBins()+1; ++ibin) {
      double term0     = _h_brB[1][ix]->bin(ibin).sumW()   +_h_brB[3][ix]->bin(ibin).sumW();
      double term0Err2 = _h_brB[1][ix]->bin(ibin).sumW2()  +_h_brB[3][ix]->bin(ibin).sumW2();
      double term1     = _h_brB[0][ix]->bin(ibin).sumW()   +_h_brB[2][ix]->bin(ibin).sumW();
      double term1Err2 = _h_brB[0][ix]->bin(ibin).sumW2()  +_h_brB[2][ix]->bin(ibin).sumW2();
      double val(0.),err(0.);
      if(term0>0. && term1>0.) {
        val = (term0-term1)/(term0+term1);
        err = 4.*(sqr(term1)*term0Err2 + sqr(term0)*term1Err2)/pow(term0+term1,4);
      }
      RK->bin(ibin).set(val, err);
    }
      }
    }

    /// @}


    /// @name Histograms
    /// @{
    CounterPtr _c[2];
    Histo1DPtr _h_br[4][3],_h_brB[4][3];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(BELLE_2021_I1748231);

}