Rivet analyses

Mass distributions in B̄0 → Λc+Λ̄c−K̄0

Experiment: BELLE (KEKB)

Inspire ID: 1679584

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Eur.Phys.J.C 78 (2018) 11, 928

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0, originally e+e- at Upsilon(4S)

Mass distributions in B̄0 → Λc+Λ̄c−K̄0. Data read from plots and sidebands given subtracted.

Source code:BELLE_2018_I1679584.cc

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

namespace Rivet {


  /// @brief Bbar0 -> Lambda_c+ Lambdabar_c- Kbar0
  class BELLE_2018_I1679584 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2018_I1679584);


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

    /// Book histograms and initialise projections before the run
    void init() {
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511);
      declare(ufs, "UFS");
      DecayedParticles B0(ufs);
      B0.addStable(4122);
      B0.addStable(-4122);
      B0.addStable(310);
      declare(B0, "B0");
      // histos
      for (unsigned int ix = 0; ix < 2; ++ix) book(_h[ix], 1 + ix, 1, 1);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{4122, 1}, {-4122, 1}, {310, 1}};
      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
      // loop over particles
      for (unsigned int ix = 0; ix < B0.decaying().size(); ++ix) {
        if (!B0.modeMatches(ix, 3, mode)) continue;
        const Particle& LamC = B0.decayProducts()[ix].at(4122)[0];
        const Particle& LamCBar = B0.decayProducts()[ix].at(-4122)[0];
        const Particle& K0 = B0.decayProducts()[ix].at(310)[0];
        if (B0.decaying()[ix].pid() < 0)
          _h[0]->fill((LamC.momentum() + K0.momentum()).mass());
        else
          _h[0]->fill((LamCBar.momentum() + K0.momentum()).mass());
        _h[1]->fill((LamC.momentum() + LamCBar.momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 2; ++ix) normalize(_h[ix], 1., false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[2];
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2018_I1679584);

}