Rivet analyses

Mass distributions in Ωc0 decays

Experiment: BELLE (KEKB)

Inspire ID: 1641071

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 97 (2018) 3, 032001

Beams: * *

Beam energies: ANY

Run details: - Any process producing Omega_c

Measurement of the mass distributions in the decays Ωc0 → Ω−π+π0, Ξ−K+π+π+ and Ξ0K−π+ . The data were read from the plots in the paper and are not corrected.

Source code:BELLE_2018_I1641071.cc

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

namespace Rivet {


  /// @brief Omega_c decays
  class BELLE_2018_I1641071 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2018_I1641071);


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

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 4332);
      declare(ufs, "UFS");
      DecayedParticles OMEGAC(ufs);
      OMEGAC.addStable(PID::PI0);
      OMEGAC.addStable(PID::K0S);
      OMEGAC.addStable(PID::XIMINUS);
      OMEGAC.addStable(-PID::XIMINUS);
      OMEGAC.addStable(PID::XI0);
      OMEGAC.addStable(-PID::XI0);
      OMEGAC.addStable(PID::OMEGAMINUS);
      OMEGAC.addStable(-PID::OMEGAMINUS);
      declare(OMEGAC, "OMEGAC");
      for (unsigned int ix = 0; ix < 4; ++ix) book(_h[ix], 1, 1, 1 + ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{3334, 1}, {211, 1}, {111, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{-3334, 1}, {-211, 1}, {111, 1}};
      static const map<PdgId, unsigned int>& mode2 = {{3312, 1}, {-321, 1}, {211, 2}};
      static const map<PdgId, unsigned int>& mode2CC = {{-3312, 1}, {321, 1}, {-211, 2}};
      static const map<PdgId, unsigned int>& mode3 = {{3322, 1}, {-321, 1}, {211, 1}};
      static const map<PdgId, unsigned int>& mode3CC = {{-3322, 1}, {321, 1}, {-211, 1}};
      DecayedParticles OMEGAC = apply<DecayedParticles>(event, "OMEGAC");
      // loop over particles
      for (unsigned int ix = 0; ix < OMEGAC.decaying().size(); ++ix) {
        int sign = OMEGAC.decaying()[ix].pid() / OMEGAC.decaying()[ix].abspid();
        // omega pi+ pi0
        if ((sign == 1 && OMEGAC.modeMatches(ix, 3, mode1))
            || (sign == -1 && OMEGAC.modeMatches(ix, 3, mode1CC))) {
          const Particle& pi0 = OMEGAC.decayProducts()[ix].at(111)[0];
          const Particle& pip = OMEGAC.decayProducts()[ix].at(sign * 211)[0];
          _h[0]->fill((pi0.momentum() + pip.momentum()).mass());
        }
        // Xi- K- pi+pi+
        else if ((sign == 1 && OMEGAC.modeMatches(ix, 4, mode2))
                 || (sign == -1 && OMEGAC.modeMatches(ix, 4, mode2CC))) {
          const Particles& pip = OMEGAC.decayProducts()[ix].at(sign * 211);
          const Particle& Km = OMEGAC.decayProducts()[ix].at(-sign * 321)[0];
          const Particle& xim = OMEGAC.decayProducts()[ix].at(sign * 3312)[0];
          _h[1]->fill((xim.momentum() + pip[0].momentum()).mass());
          _h[1]->fill((xim.momentum() + pip[1].momentum()).mass());
          _h[2]->fill((Km.momentum() + pip[0].momentum()).mass());
          _h[2]->fill((Km.momentum() + pip[1].momentum()).mass());
        }
        // Xi0 K- pi+
        else if ((sign == 1 && OMEGAC.modeMatches(ix, 3, mode3))
                 || (sign == -1 && OMEGAC.modeMatches(ix, 3, mode3CC))) {
          const Particle& pip = OMEGAC.decayProducts()[ix].at(sign * 211)[0];
          const Particle& Km = OMEGAC.decayProducts()[ix].at(-sign * 321)[0];
          _h[3]->fill((Km.momentum() + pip.momentum()).mass());
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 4; ++ix) normalize(_h[ix]);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[4];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2018_I1641071);

}