Rivet analyses

title: BELLE_2015_I1392799

Mass and angular distributions in $B^0\to p\bar{\Lambda}^0D^{(*)-}$

Experiment: BELLE (KEKB)

Inspire ID: 1392799

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 115 (2015) 22, 221803

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0, original Upsilon(4S) decay

Measurement of the mass and angular distributions in $B^0\to p\bar{\Lambda}^0D^{(*)-}$. Data read from plots but is corrected for efficiency.

Source code:BELLE_2015_I1392799.cc

```c++ // -- C++ --

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B -> p Lambda D class BELLE_2015_I1392799 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2015_I1392799);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511);
  declare(ufs, "UFS");
  DecayedParticles B0(ufs);
  B0.addStable(411);
  B0.addStable(-411);
  B0.addStable(413);
  B0.addStable(-413);
  B0.addStable(PID::LAMBDA);
  B0.addStable(-PID::LAMBDA);
  declare(B0, "B0");
  //histograms
  for (unsigned int ix = 0; ix < 2; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) {
      book(_h[ix][iy], 1 + ix, 1, 1 + iy);
    }
  }
  book(_nB, "/TMP/nb");
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{2212, 1}, {-3122, 1}, {-411, 1}};
  static const map<PdgId, unsigned int>& mode1CC = {{-2212, 1}, {3122, 1}, {411, 1}};
  static const map<PdgId, unsigned int>& mode2 = {{2212, 1}, {-3122, 1}, {-413, 1}};
  static const map<PdgId, unsigned int>& mode2CC = {{-2212, 1}, {3122, 1}, {413, 1}};
  DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
  // loop over particles
  for (unsigned int ix = 0; ix < B0.decaying().size(); ++ix) {
    _nB->fill();
    int sign = 1, imode = 0;
    if (B0.decaying()[ix].pid() > 0 && B0.modeMatches(ix, 3, mode1)) {
      imode = 0;
      sign = 1;
    }
    else if (B0.decaying()[ix].pid() < 0 && B0.modeMatches(ix, 3, mode1CC)) {
      imode = 0;
      sign = -1;
    }
    else if (B0.decaying()[ix].pid() > 0 && B0.modeMatches(ix, 3, mode2)) {
      imode = 1;
      sign = 1;
    }
    else if (B0.decaying()[ix].pid() < 0 && B0.modeMatches(ix, 3, mode2CC)) {
      imode = 1;
      sign = -1;
    }
    else
      continue;
    int iD = imode == 0 ? 411 : 413;
    const Particle& pp = B0.decayProducts()[ix].at(sign * 2212)[0];
    const Particle& lam = B0.decayProducts()[ix].at(-sign * 3122)[0];
    const Particle& Dm = B0.decayProducts()[ix].at(-sign * iD)[0];
    _h[0][imode]->fill((lam.momentum() + pp.momentum()).mass());
    // first boost to B rest frame
    LorentzTransform boostB = LorentzTransform::mkFrameTransformFromBeta(
        B0.decaying()[ix].momentum().betaVec());
    FourMomentum ppp = boostB.transform(pp.momentum());
    FourMomentum plam = boostB.transform(lam.momentum());
    FourMomentum pDm = boostB.transform(Dm.momentum());
    LorentzTransform boostpLam = LorentzTransform::mkFrameTransformFromBeta((ppp + plam).betaVec());
    ppp = boostpLam.transform(ppp);
    pDm = boostpLam.transform(pDm);
    _h[1][imode]->fill(ppp.p3().unit().dot(pDm.p3().unit()));
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 2; ++ix) {
    double fact = ix == 0 ? 1e3 : 1e6;
    for (unsigned int iy = 0; iy < 2; ++iy) {
      scale(_h[ix][iy], fact / *_nB);
    }
  }
}

/// @}


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

};

RIVET_DECLARE_PLUGIN(BELLE_2015_I1392799);

} ```