Rivet analyses

title: ARGUS_1994_I354224

$K^0_s$ production in B decays

Experiment: ARGUS (DORIS)

Inspire ID: 354224

Status: VALIDATED

Authors: - Peter Richardson

References: - Z.Phys. C62 (1994) 371-382, 1994

Beams: * *

Beam energies: ANY

Run details: - In principle any process producing $B^\pm$ and $B^0,\bar{B}^0$, bot original at Upsilon 4S

Measurement of the spectrum for $K^0_S$ production in $B$ decays. The original measurement was done by ARGUS at the $\Upsilon(4S)$ resonance and therefore represents that admixture of $B^\pm$ and $B^0,\bar{B}^0$.

Source code:ARGUS_1994_I354224.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief k0s in b decays class ARGUS_1994_I354224 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1994_I354224);


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

/// Book histograms and initialise projections before the run
void init() {

  // Initialise and register projections
  declare(UnstableParticles(), "UFS");

  // Book histograms
  book(_h_K, "TMP/h_K", refData(1, 1, 1));
  book(_nB, "TMP/nB");
}

void analyzeDecay(Particle mother, Particles& kaons) {
  for (const Particle& p : mother.children()) {
    if (p.pid() == 310) {
      kaons.push_back(p);
    }
    else if (!p.children().empty()) {
      analyzeDecay(p, kaons);
    }
  }
}

/// Perform the per-event analysis
void analyze(const Event& event) {
  for (const Particle& p :
       apply<UnstableParticles>(event, "UFS").particles(Cuts::abspid == 511 or Cuts::abspid == 521)) {
    if (!p.children().empty()) {
      if (p.children()[0].pid() == p.pid()) continue;
    }
    FourMomentum pB = p.momentum();
    const LorentzTransform B_boost = LorentzTransform::mkFrameTransformFromBeta(pB.betaVec());
    _nB->fill();
    Particles kaons;
    analyzeDecay(p, kaons);
    for (const Particle& kaon : kaons) {
      FourMomentum pKaon = B_boost.transform(kaon.momentum());
      _h_K->fill(pKaon.p3().mod());
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {

  scale(_h_K, 1. / *_nB);
  Estimate1DPtr tmp;
  book(tmp, 1, 1, 1);
  barchart(_h_K, tmp);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_K;
Estimate1DPtr _est_K;
CounterPtr _nB;
/// @}

};

RIVET_DECLARE_PLUGIN(ARGUS_1994_I354224);

} ```