Rivet analyses

Mass distributions in B̄⁰ → D^*0π⁺π⁺π⁻π⁻

Experiment: CLEOII (CESR)

Inspire ID: 557084

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: none listed

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0 mesons, originally Upsilon(4S) decays

Measurement of mass distributions in B̄⁰ → D^*0π⁺π⁺π⁻π⁻. The data were read from the figures in the paper. All the data is background subracted and that for the 4π mass distribution efficiency corrected.

Source code:`CLEOII_2002_I557084.cc`

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

namespace Rivet {


  /// @brief Bbar0 -> D*0 2pi+2pi-
  class CLEOII_2002_I557084 : public Analysis {
  public:

    /// Constructor
    RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_2002_I557084);


    /// @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(411);
      B0.addStable(-411);
      B0.addStable(421);
      B0.addStable(-421);
      B0.addStable(431);
      B0.addStable(-431);
      declare(B0, "B0");
      // histos
      for (unsigned int ix = 0; ix < 2; ++ix) {
        book(_h_Dpi[ix], 1, 1, 1 + ix);
        book(_h_4pi[ix], 3, 1, 1 + ix);
      }
      book(_h_3pi, 2, 1, 1);
      book(_c, "TMP/nB");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // loop over particles
      DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
      int imode = -1;
      for (unsigned int ix = 0; ix < B0.decaying().size(); ++ix) {
        int sign = B0.decaying()[ix].pid() / B0.decaying()[ix].abspid();
        _c->fill();
        if ((sign == 1 && B0.modeMatches(ix, 5, mode1)) || (sign == -1 && B0.modeMatches(ix, 5, mode1CC))) {
          imode = 0;
        }
        else if ((sign == 1 && B0.modeMatches(ix, 5, mode2))
                 || (sign == -1 && B0.modeMatches(ix, 5, mode2CC))) {
          imode = 1;
        }
        else {
          continue;
        }
        const Particles& pip = B0.decayProducts()[ix].at(sign * 211);
        const Particles& pim = B0.decayProducts()[ix].at(-sign * 211);
        FourMomentum pTotal;
        for (const Particle& p : pip) pTotal += p.mom();
        for (const Particle& p : pim) pTotal += p.mom();
        if (imode == 0) {
          const Particle& pi0 = B0.decayProducts()[ix].at(111)[0];
          pTotal += pi0.mom();
          _h_4pi[1]->fill(pTotal.mass2());
          continue;
        }
        _h_4pi[0]->fill(pTotal.mass2());
        // D* pi mases
        const Particle& Dstar = B0.decayProducts()[ix].at(-sign * 423)[0];
        for (const Particle& p : pim) {
          FourMomentum pDpi = Dstar.mom() + p.mom();
          const double mDpi = pDpi.mass();
          _h_Dpi[0]->fill(mDpi);
          if (mDpi > 2.3 and mDpi < 2.6) {
            FourMomentum p3pi = B0.decaying()[ix].mom() - pDpi;
            _h_3pi->fill(p3pi.mass());
          }
        }
        for (const Particle& p : pip) {
          _h_Dpi[1]->fill((Dstar.mom() + p.mom()).mass());
        }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      // first hist is differential BR/ BR for leptons
      const double br = .1033;
      normalize(_h_Dpi, 1.0, false);
      scale(_h_4pi, 1.0 / br / *_c);
      normalize(_h_3pi, 1., false);
    }

    /// @}


    /// @name Histograms
    /// @{
    Histo1DPtr _h_Dpi[2], _h_3pi, _h_4pi[2];
    CounterPtr _c;
    const map<PdgId, unsigned int> mode1 = {{-413, 1}, {211, 2}, {-211, 1}, {111, 1}};
    const map<PdgId, unsigned int> mode1CC = {{413, 1}, {-211, 2}, {211, 1}, {111, 1}};
    const map<PdgId, unsigned int> mode2 = {{-423, 1}, {211, 2}, {-211, 2}};
    const map<PdgId, unsigned int> mode2CC = {{423, 1}, {211, 2}, {-211, 2}};
    /// @}
  };


  RIVET_DECLARE_PLUGIN(CLEOII_2002_I557084);

}

Rivet analyses

Mass distributions in B̄0 → D*0π+π+π−π−

Source code:CLEOII_2002_I557084.cc

Mass distributions in B̄⁰ → D^*0π⁺π⁺π⁻π⁻

Source code:`CLEOII_2002_I557084.cc`