Rivet analyses

Mass distributions in Bc+ decays to charmonia + multihadron final states

Experiment: LHCB (LHC)

Inspire ID: 2138845

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - arXiv: 2208.08660

Beams: * *

Beam energies: ANY

Run details: - Any process producing B_c+, originally pp

Mass distributions in Bc+ decays to charmonia + multihadron final states. The data were read from the plots in the paper and may not be corrected for efficiency and acceptance.

Source code:LHCB_2022_I2138845.cc

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

namespace Rivet {


  /// @brief B_c to ccbar + hadrons
  class LHCB_2022_I2138845 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2022_I2138845);


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

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::abspid==541);
      declare(ufs, "UFS");
      DecayedParticles BC(ufs);
      BC.addStable( PID::PI0);
      BC.addStable( PID::K0S);
      BC.addStable( PID::JPSI);
      BC.addStable( PID::PSI2S);
      declare(BC, "BC");
      for(unsigned int ix=0;ix<3;++ix)
    book(_h[ix],1,1,1+ix);
      for(unsigned int ix=0;ix<2;++ix) {
    book(_h[ix+3],2,1,1+ix);
    book(_h[ix+5],3,1,1+ix);
    book(_h[ix+7],4,1,1+ix);
      }
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId,unsigned int> & mode1   = { { 443,1}, { 211,3}, {-211,2} };
      static const map<PdgId,unsigned int> & mode1CC = { { 443,1}, {-211,3}, { 211,2} };
      static const map<PdgId,unsigned int> & mode2   = { { 443,1}, { 321,1}, {-321,1}, { 211,2}, {-211,1} };
      static const map<PdgId,unsigned int> & mode2CC = { { 443,1}, { 321,1}, {-321,1}, {-211,2}, { 211,1} };
      static const map<PdgId,unsigned int> & mode3   = { { 443,1}, { 211,4}, {-211,3} };
      static const map<PdgId,unsigned int> & mode3CC = { { 443,1}, {-211,4}, { 211,3} };
      static const map<PdgId,unsigned int> & mode4   = { { 100443,1}, { 211,2}, {-211,1} };
      static const map<PdgId,unsigned int> & mode4CC = { { 100443,1}, {-211,2}, { 211,1} };
      DecayedParticles BC = apply<DecayedParticles>(event, "BC");
      // loop over particles
      for(unsigned int ix=0;ix<BC.decaying().size();++ix) {
    int sign = BC.decaying()[ix].pid()/BC.decaying()[ix].abspid();
    if ((sign== 1 && BC.modeMatches(ix,6,mode1  )) ||
        (sign==-1 && BC.modeMatches(ix,6,mode1CC))) {
      const Particles & pim = BC.decayProducts()[ix].at(-sign*211);
      const Particles & pip = BC.decayProducts()[ix].at( sign*211);
      FourMomentum ptotal=pim[0].momentum()+pim[1].momentum()+
        pip[0].momentum()+pip[1].momentum()+pip[2].momentum();
      _h[0]->fill(ptotal.mass());
      for(unsigned int ix=0;ix<3;++ix)
        for(unsigned int iy=0;iy<2;++iy) {
          FourMomentum prho=pip[ix].momentum()+pim[iy].momentum();
          _h[3]->fill((ptotal-prho).mass());
          _h[5]->fill(prho.mass());
        }
    }
    else if ((sign== 1 && BC.modeMatches(ix,6,mode2  )) ||
         (sign==-1 && BC.modeMatches(ix,6,mode2CC))) {
      const Particles & pim = BC.decayProducts()[ix].at(-sign*211);
      const Particles & pip = BC.decayProducts()[ix].at( sign*211);
      const Particle  & Kp  = BC.decayProducts()[ix].at( sign*321)[0];
      const Particle  & Km  = BC.decayProducts()[ix].at(-sign*321)[0];
      _h[1]->fill((Kp.momentum()+Km.momentum()+pim[0].momentum()+
               pip[0].momentum()+pip[1].momentum()).mass());
      _h[7]->fill((Kp.momentum()+pim[0].momentum()).mass());
      _h[7]->fill((Km.momentum()+pip[0].momentum()).mass());
      _h[7]->fill((Km.momentum()+pip[1].momentum()).mass());
      _h[8]->fill((Kp.momentum()+Km.momentum()).mass());
    }
    else if ((sign== 1 && BC.modeMatches(ix,8,mode3  )) ||
         (sign==-1 && BC.modeMatches(ix,8,mode3CC))) {
      const Particles & pim = BC.decayProducts()[ix].at(-sign*211);
      const Particles & pip = BC.decayProducts()[ix].at( sign*211);
      _h[2]->fill((pim[0].momentum()+pim[1].momentum()+pim[2].momentum()+
               pip[0].momentum()+pip[1].momentum()+pip[2].momentum()+pip[3].momentum()).mass());
    }
    else if ((sign== 1 && BC.modeMatches(ix,4,mode4  )) ||
         (sign==-1 && BC.modeMatches(ix,4,mode4CC))) {
      const Particles & pim = BC.decayProducts()[ix].at(-sign*211);
      const Particles & pip = BC.decayProducts()[ix].at( sign*211);
      _h[4]->fill((pim[0].momentum()+
               pip[0].momentum()+pip[1].momentum()).mass());
      for(unsigned int iy=0;iy<2;++iy)
        _h[6]->fill((pim[0].momentum()+pip[ix].momentum()).mass());
    }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for(unsigned int ix=0;ix<9;++ix)
    normalize(_h[ix],1.,false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[9];
    /// @}


  };


  RIVET_DECLARE_PLUGIN(LHCB_2022_I2138845);

}