Rivet analyses

title: BABAR_2009_I801589

Mass and angular distributions in $B^0\to K^+\pi^- (J/\psi,\psi(2S))$ and $B^+\to K^0_S\pi^+(J/\psi,\psi(2S))$

Experiment: BABAR (PEP-II)

Inspire ID: 801589

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 79 (2009) 112001

Beams: * *

Beam energies: ANY

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

Mass and angular distributions in $B^0\to K^+\pi^- (J/\psi,\psi(2S))$ and $B^+\to K^0_S\pi^+(J/\psi,\psi(2S))$. The corrected, background subtracted data was read from the figures in the paper.

Source code:BABAR_2009_I801589.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B -> J/psi / psi(2S) K pi class BABAR_2009_I801589 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BABAR_2009_I801589);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 511 || Cuts::abspid == 521);
  declare(ufs, "UFS");
  DecayedParticles BB(ufs);
  BB.addStable(310);
  BB.addStable(443);
  BB.addStable(100443);
  declare(BB, "BB");
  // histos
  for (unsigned int ix = 0; ix < 2; ++ix) {
    book(_h_Kpi2[ix], 2, 1, 1 + ix);
    book(_h_angle[ix], 4, 1, 1 + ix);
    book(_c[ix], "TMP/c_" + toString(ix));
    for (unsigned int iy = 0; iy < 2; ++iy) {
      book(_h_Kpi[ix][iy], 1, 1 + ix, 1 + iy);
    }
    book(_b[ix], {0., .795, .995, 1.332, 1.532, 10.});
    for (unsigned int iy = 0; iy < 5; ++iy) book(_b[ix]->bin(iy + 1), 3, 1 + ix, 1 + iy);
    for (unsigned int iy = 0; iy < 3; ++iy) {
      book(_h_PsiPi[ix][iy], 5, 1 + ix, 1 + iy);
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode1 = {{321, 1}, {-211, 1}, {443, 1}};
  static const map<PdgId, unsigned int>& mode1CC = {{-321, 1}, {211, 1}, {443, 1}};
  static const map<PdgId, unsigned int>& mode2 = {{321, 1}, {-211, 1}, {100443, 1}};
  static const map<PdgId, unsigned int>& mode2CC = {{-321, 1}, {211, 1}, {100443, 1}};
  static const map<PdgId, unsigned int>& mode3 = {{310, 1}, {-211, 1}, {443, 1}};
  static const map<PdgId, unsigned int>& mode3CC = {{310, 1}, {211, 1}, {443, 1}};
  static const map<PdgId, unsigned int>& mode4 = {{310, 1}, {-211, 1}, {100443, 1}};
  static const map<PdgId, unsigned int>& mode4CC = {{310, 1}, {211, 1}, {100443, 1}};
  DecayedParticles BB = apply<DecayedParticles>(event, "BB");
  // loop over particles
  for (unsigned int ix = 0; ix < BB.decaying().size(); ++ix) {
    int sign = 1, iK(0), iPsi(0);
    if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode1)) {
      sign = 1;
      iK = 321;
      iPsi = 443;
    }
    else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode1CC)) {
      sign = -1;
      iK = -321;
      iPsi = 443;
    }
    else if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode2)) {
      sign = 1;
      iK = 321;
      iPsi = 100443;
    }
    else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode2CC)) {
      sign = -1;
      iK = -321;
      iPsi = 100443;
    }
    else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode3)) {
      sign = 1;
      iK = 310;
      iPsi = 443;
    }
    else if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode3CC)) {
      sign = -1;
      iK = 310;
      iPsi = 443;
    }
    else if (BB.decaying()[ix].pid() < 0 && BB.modeMatches(ix, 3, mode4)) {
      sign = 1;
      iK = 310;
      iPsi = 100443;
    }
    else if (BB.decaying()[ix].pid() > 0 && BB.modeMatches(ix, 3, mode4CC)) {
      sign = -1;
      iK = 310;
      iPsi = 100443;
    }
    else
      continue;
    _c[iPsi / 100000]->fill();
    const Particle& Kp = BB.decayProducts()[ix].at(iK)[0];
    const Particle& pim = BB.decayProducts()[ix].at(-211 * sign)[0];
    const Particle& psi = BB.decayProducts()[ix].at(iPsi)[0];
    FourMomentum pKpi = Kp.momentum() + pim.momentum();
    double mKpi = pKpi.mass();
    _h_Kpi[BB.decaying()[ix].abspid() % 100 / 10 - 1][iPsi / 100000]->fill(mKpi);
    _h_Kpi2[iPsi / 100000]->fill(mKpi);
    double mPsiPi = (psi.momentum() + pim.momentum()).mass();
    _b[iPsi / 100000]->fill(mKpi, mPsiPi);
    _h_PsiPi[iPsi / 100000][0]->fill(mPsiPi);
    // helicity angle
    if (mKpi < 0.795 || (mKpi > 0.995 && mKpi < 1.332) || mKpi > 1.532) {
      _h_PsiPi[iPsi / 100000][2]->fill(mPsiPi);
      LorentzTransform boost1 = LorentzTransform::mkFrameTransformFromBeta(
          BB.decaying()[ix].momentum().betaVec());
      pKpi = boost1.transform(pKpi);
      Vector3 axis1 = pKpi.p3().unit();
      LorentzTransform boost3 = LorentzTransform::mkFrameTransformFromBeta(pKpi.betaVec());
      FourMomentum ppi = boost3.transform(boost1.transform(pim.momentum()));
      double cPi = ppi.p3().unit().dot(axis1);
      _h_angle[iPsi / 100000]->fill(cPi);
    }
    else {
      _h_PsiPi[iPsi / 100000][1]->fill(mPsiPi);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 2; ++ix) {
    normalize(_h_Kpi2[ix], 1., false);
    normalize(_h_angle[ix], 1., false);
    for (unsigned int iy = 0; iy < 2; ++iy) {
      normalize(_h_Kpi[ix][iy], 1., false);
    }
    for (unsigned int iy = 0; iy < 3; ++iy) {
      scale(_h_PsiPi[ix][iy], 1. / *_c[ix]);
    }
    scale(_b[ix], 1. / *_c[ix]);
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_Kpi[2][2], _h_Kpi2[2], _h_angle[2], _h_PsiPi[2][3];
Histo1DGroupPtr _b[2];
CounterPtr _c[2];
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2009_I801589);

} ```