Rivet analyses

title: BELLE_2019_I1729723

$\bar{B}^0\to K^0_SK^\mp\pi^\pm$

Experiment: BELLE (KEKB)

Inspire ID: 1729723

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 100 (2019) 1, 011101

Beams: * *

Beam energies: ANY

Run details: - Any process producing B0 originally e+e- at Upsilon(4S)

Measurement of the mass distributions in the decays $\bar{B}^0\to K^0_SK^\mp\pi^\pm$. The data were read from the plots in the paper, but is corrected for detector efficiency.

Source code:BELLE_2019_I1729723.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief B0 -> KS0 K-+ pi+- class BELLE_2019_I1729723 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(BELLE_2019_I1729723);


/// @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(PID::K0S);
  B0.addStable(PID::ETA);
  B0.addStable(PID::ETAPRIME);
  declare(B0, "B0");
  for (unsigned int ix = 0; ix < 3; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) {
      book(_h[ix][iy], 1 + ix, 1, 1 + iy);
    }
  }
  book(_n, "TMP/nB0");
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const map<PdgId, unsigned int>& mode = {{310, 1}, {-321, 1}, {211, 1}};
  static const map<PdgId, unsigned int>& modeCC = {{310, 1}, {321, 1}, {-211, 1}};
  DecayedParticles B0 = apply<DecayedParticles>(event, "B0");
  // loop over particles
  for (unsigned int ix = 0; ix < B0.decaying().size(); ++ix) {
    _n->fill();
    unsigned int iloc(0);
    int sign = 1;
    if (B0.modeMatches(ix, 3, mode)) {
      sign = 1;
      iloc = B0.decaying()[ix].pid() > 0 ? 1 : 0;
    }
    else if (B0.modeMatches(ix, 3, modeCC)) {
      sign = -1;
      iloc = B0.decaying()[ix].pid() > 0 ? 0 : 1;
    }
    else
      continue;
    const Particle& pip = B0.decayProducts()[ix].at(sign * 211)[0];
    const Particle& Km = B0.decayProducts()[ix].at(-sign * 321)[0];
    const Particle& K0 = B0.decayProducts()[ix].at(310)[0];
    _h[0][iloc]->fill((Km.momentum() + pip.momentum()).mass());
    _h[1][iloc]->fill((K0.momentum() + pip.momentum()).mass());
    _h[2][iloc]->fill((Km.momentum() + K0.momentum()).mass());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 3; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) {
      scale(_h[ix][iy], 1e7 / *_n);
    }
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[3][2];
CounterPtr _n;
/// @}

};

RIVET_DECLARE_PLUGIN(BELLE_2019_I1729723);

} ```