Rivet analyses

title: CLEOII_2002_I557084

Mass distributions in $\bar{B}^0\to D^{*0}\pi^+\pi^+\pi^-\pi^-$

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 $\bar{B}^0\to D^{*0}\pi^+\pi^+\pi^-\pi^-$. The data were read from the figures in the paper. All the data is background subracted and that for the $4\pi$ mass distribution efficiency corrected.

Source code:CLEOII_2002_I557084.cc

```c++ // -- 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);

} ```