Rivet analyses

B̄s0 → Λc+Λ̄0π− Differential branching ratios

Experiment: BELLE (KEKB)

Inspire ID: 1230342

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Lett.B 726 (2013) 206-210

Beams: * *

Beam energies: ANY

Run details: - Any process producing BS0, originially e+e- at Upsilon(5S)

Differential branching ratios for B̄s0 → Λc+Λ̄0π− with respect to the invariant masses of pairs of the decay products.

Source code:BELLE_2013_I1230342.cc

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

namespace Rivet {


  /// @brief BbarS0 -> Lambda_c+ Lambdabar0 pi-
  class BELLE_2013_I1230342 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2013_I1230342);


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

    /// Book histograms and initialise projections before the run
    void init() {
      // Initialise and register projections
      UnstableParticles ufs = UnstableParticles(Cuts::abspid == 531);
      declare(ufs, "UFS");
      DecayedParticles BS0(ufs);
      BS0.addStable(3122);
      BS0.addStable(-3122);
      BS0.addStable(4122);
      BS0.addStable(-4122);
      declare(BS0, "BS0");
      // histos
      book(_c, "TMP/nB");
      for (unsigned int ix = 0; ix < 3; ++ix) book(_h[ix], 1, 1, 1 + ix);
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode = {{4122, 1}, {-3122, 1}, {-211, 1}};
      static const map<PdgId, unsigned int>& modeCC = {{-4122, 1}, {3122, 1}, {211, 1}};
      DecayedParticles BS0 = apply<DecayedParticles>(event, "BS0");
      // loop over particles
      for (unsigned int ix = 0; ix < BS0.decaying().size(); ++ix) {
        _c->fill();
        int sign = 1;
        if (BS0.decaying()[ix].pid() < 0 && BS0.modeMatches(ix, 3, mode)) {
          sign = 1;
        }
        else if (BS0.decaying()[ix].pid() > 0 && BS0.modeMatches(ix, 3, modeCC)) {
          sign = -1;
        }
        else
          continue;
        const Particle& LamC = BS0.decayProducts()[ix].at(sign * 4122)[0];
        const Particle& LamBar = BS0.decayProducts()[ix].at(-sign * 3122)[0];
        const Particle& pim = BS0.decayProducts()[ix].at(-sign * 211)[0];
        _h[0]->fill((LamC.momentum() + LamBar.momentum()).mass());
        _h[1]->fill((LamC.momentum() + pim.momentum()).mass());
        _h[2]->fill((pim.momentum() + LamBar.momentum()).mass());
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      for (unsigned int ix = 0; ix < 3; ++ix) scale(_h[ix], 1e4 / *_c);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h[3];
    CounterPtr _c;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BELLE_2013_I1230342);

}