Rivet analyses

title: CLEOII_1996_I415408

Mass distributions in $\tau$ decays with $K^0_S$ mesons

Experiment: CLEOII (CESR)

Inspire ID: 415408

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.D 53 (1996) 6037-6053

Beams: * *

Beam energies: ANY

Run details: - Any process producing tau leptons, originally e+e-

Mass distributions in the decays $\tau\to\nu_\tau+K^0_S\pi^-$, $K^-K^0_S$, $K^0_S\pi^-\pi^0$, $K^0_SK^-\pi^0$ and $K^0_SK^0_S\pi^-$. The background subtracted data were read from the figures in the paper.

Source code:CLEOII_1996_I415408.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief tau -> hadrons with KS0 class CLEOII_1996_I415408 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEOII_1996_I415408);


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

/// Book histograms and initialise projections before the run
void init() {
  // Initialise and register projections
  UnstableParticles ufs = UnstableParticles(Cuts::abspid == 15);
  declare(ufs, "UFS");
  DecayedParticles TAU(ufs);
  TAU.addStable(310);
  TAU.addStable(111);
  declare(TAU, "TAU");
  // histos
  for (unsigned int ix = 0; ix < 4; ++ix) {
    book(_h[ix], 1 + ix, 1, 1);
    if (ix > 1) continue;
    book(_h[4 + ix], 5, 1, 1 + ix);
    book(_h[6 + ix], 6 + ix, 1, 1);
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  DecayedParticles TAU = apply<DecayedParticles>(event, "TAU");
  // loop over particles
  for (unsigned int ix = 0; ix < TAU.decaying().size(); ++ix) {
    int sign = TAU.decaying()[ix].pid() > 0 ? 1 : -1;
    if ((TAU.modeMatches(ix, 3, mode1) || TAU.modeMatches(ix, 3, mode1CC))) {
      const Particle& pim = TAU.decayProducts()[ix].at(-211 * sign)[0];
      const Particle& K0 = TAU.decayProducts()[ix].at(310)[0];
      _h[0]->fill((pim.mom() + K0.mom()).mass());
    }
    else if (TAU.modeMatches(ix, 3, mode2) || TAU.modeMatches(ix, 3, mode2CC)) {
      const Particle& Km = TAU.decayProducts()[ix].at(-321 * sign)[0];
      const Particle& K0 = TAU.decayProducts()[ix].at(310)[0];
      _h[1]->fill((Km.mom() + K0.mom()).mass());
    }
    else if (TAU.modeMatches(ix, 4, mode3) || TAU.modeMatches(ix, 4, mode3CC)) {
      const Particle& pim = TAU.decayProducts()[ix].at(-211 * sign)[0];
      const Particle& K0 = TAU.decayProducts()[ix].at(310)[0];
      const Particle& pi0 = TAU.decayProducts()[ix].at(111)[0];
      _h[2]->fill((pim.mom() + K0.mom() + pi0.mom()).mass());
    }
    else if (TAU.modeMatches(ix, 4, mode4) || TAU.modeMatches(ix, 4, mode4CC)) {
      const Particle& Km = TAU.decayProducts()[ix].at(-321 * sign)[0];
      const Particle& K0 = TAU.decayProducts()[ix].at(310)[0];
      const Particle& pi0 = TAU.decayProducts()[ix].at(111)[0];
      _h[3]->fill((Km.mom() + K0.mom() + pi0.mom()).mass());
      _h[4]->fill((Km.mom() + pi0.mom()).mass());
      _h[5]->fill((K0.mom() + pi0.mom()).mass());
    }
    else if (TAU.modeMatches(ix, 4, mode5) || TAU.modeMatches(ix, 4, mode5CC)) {
      const Particle& pim = TAU.decayProducts()[ix].at(-211 * sign)[0];
      const Particles& K0 = TAU.decayProducts()[ix].at(310);
      _h[6]->fill((pim.mom() + K0[0].mom() + K0[1].mom()).mass());
      _h[7]->fill((pim.mom() + K0[0].mom()).mass());
      _h[7]->fill((pim.mom() + K0[1].mom()).mass());
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h, 1.0, false);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[8];
const map<PdgId, unsigned int> mode1 = {{310, 1}, {-211, 1}, {16, 1}};
const map<PdgId, unsigned int> mode1CC = {{310, 1}, {211, 1}, {-16, 1}};
const map<PdgId, unsigned int> mode2 = {{310, 1}, {-321, 1}, {16, 1}};
const map<PdgId, unsigned int> mode2CC = {{310, 1}, {321, 1}, {-16, 1}};
const map<PdgId, unsigned int> mode3 = {{310, 1}, {-211, 1}, {111, 1}, {16, 1}};
const map<PdgId, unsigned int> mode3CC = {{310, 1}, {211, 1}, {111, 1}, {-16, 1}};
const map<PdgId, unsigned int> mode4 = {{310, 1}, {-321, 1}, {111, 1}, {16, 1}};
const map<PdgId, unsigned int> mode4CC = {{310, 1}, {321, 1}, {111, 1}, {-16, 1}};
const map<PdgId, unsigned int> mode5 = {{310, 2}, {-211, 1}, {16, 1}};
const map<PdgId, unsigned int> mode5CC = {{310, 2}, {211, 1}, {-16, 1}};
/// @}

};

RIVET_DECLARE_PLUGIN(CLEOII_1996_I415408);

} ```