Rivet analyses

π⁺π⁺π⁻ mass distribution in B⁰ → D^*−π⁺π⁺π⁻

Experiment: BABAR (PEP-II)

Inspire ID: 1487722

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 94 (2016) 9, 091101

Beams: * *

Beam energies: ANY

Run details: none listed

Measurement of mass distributions of the pions in the decay B⁰ → D^*−π⁺π⁺π⁻. The data were read from, the plots in the papers and efficiency from the paper applied.

Source code:`BABAR_2016_I1487722.cc`

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

namespace Rivet {


  /// @brief B0 -> D*- pi+ pi+ pi-
  class BABAR_2016_I1487722 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2016_I1487722);


    /// @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(PID::PI0);
      B0.addStable(413);
      B0.addStable(-413);
      B0.addStable(423);
      B0.addStable(-423);
      B0.addStable(PID::PI0);
      declare(B0, "B0");
      // histograms
      book(_h, 1, 1, 1);
      // efficiency
      const Estimate1D& ref = refData(2, 1, 1);
      _edges = ref.xEdges();
      _eff = ref.vals();
    }

    double eff(double mass) {
      if (mass < _edges[0] || mass > _edges.back()) return 0.;
      for (unsigned int ix = 0; ix < _eff.size(); ++ix) {
        if (mass < _edges[ix + 1]) return _eff[ix];
      }
      return 0.;
    }

    /// Perform the per-event analysis
    void analyze(const Event& event) {
      static const map<PdgId, unsigned int>& mode1 = {{-413, 1}, {211, 2}, {-211, 1}};
      static const map<PdgId, unsigned int>& mode1CC = {{413, 1}, {-211, 2}, {211, 1}};
      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
      for (unsigned int ix = 0; ix < B0.decaying().size(); ++ix) {
        int sign = B0.decaying()[ix].pid() / B0.decaying()[ix].abspid();
        if ((sign == 1 && B0.modeMatches(ix, 4, mode1)) || (sign == -1 && B0.modeMatches(ix, 4, mode1CC))) {
          FourMomentum ptotal;
          for (const Particle& p : B0.decayProducts()[ix].at(sign * 211)) {
            ptotal += p.momentum();
          }
          for (const Particle& p : B0.decayProducts()[ix].at(-sign * 211)) {
            ptotal += p.momentum();
          }
          double m = ptotal.mass();
          _h->fill(m, eff(m));
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      normalize(_h);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h;
    vector<double> _eff;
    vector<double> _edges;
    /// @}
  };


  RIVET_DECLARE_PLUGIN(BABAR_2016_I1487722);

}

Rivet analyses

π+π+π− mass distribution in B0 → D*−π+π+π−

Source code:BABAR_2016_I1487722.cc

π⁺π⁺π⁻ mass distribution in B⁰ → D^*−π⁺π⁺π⁻

Source code:`BABAR_2016_I1487722.cc`