Rivet analyses

title: CLEO_2001_I535016

Hadronic Mass distribution in $\tau^-\to2\pi^-\pi^+3\pi^0\nu_\tau$ and $3\pi^-2\pi^+\pi^0\nu_\tau$

Experiment: CLEO (CESR)

Inspire ID: 535016

Status: VALIDATED NOHEPDATA

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 86 (2001) 4467-4471

Beams: * *

Beam energies: ANY

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

Measurement of the hadronic mass distribution in n $\tau^-\to2\pi^-\pi^+3\pi^0\nu_\tau$ and $3\pi^-2\pi^+\pi^0\nu_\tau$. The data were read from the plots in the paper and are not corrected, although the backgrounds given in the paper have been subtracted. The plots should therefore only be used for qualitative comparisons however the data is useful as there are not corrected distributions for this decay mode.

Source code:CLEO_2001_I535016.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/DecayedParticles.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief tau -> 6 pion final states class CLEO_2001_I535016 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2001_I535016);


/// @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");
  // histogram
  for (unsigned int ix = 0; ix < 2; ++ix) {
    book(_h[ix], 1, 1, 1 + ix);
  }
}


/// 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;
    int imode = -1;
    if (TAU.modeMatches(ix, 7, mode1) || TAU.modeMatches(ix, 7, mode1CC))
      imode = 0;
    else if (TAU.modeMatches(ix, 7, mode2) || TAU.modeMatches(ix, 7, mode2CC))
      imode = 1;
    else
      continue;
    const Particles& pip = TAU.decayProducts()[ix].at(211 * sign);
    const Particles& pim = TAU.decayProducts()[ix].at(-211 * sign);
    const Particles& pi0 = TAU.decayProducts()[ix].at(111);
    FourMomentum ptotal;
    for (unsigned int ix = 0; ix < pim.size(); ++ix) ptotal += pim[ix].momentum();
    for (unsigned int ix = 0; ix < pip.size(); ++ix) ptotal += pip[ix].momentum();
    for (unsigned int ix = 0; ix < pi0.size(); ++ix) ptotal += pi0[ix].momentum();
    _h[imode]->fill(ptotal.mass());
  }
}


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

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h[2];
const map<PdgId, unsigned int> mode1 = {{-211, 2}, {211, 1}, {111, 3}, {16, 1}};
const map<PdgId, unsigned int> mode1CC = {{211, 2}, {-211, 1}, {111, 3}, {-16, 1}};
const map<PdgId, unsigned int> mode2 = {{-211, 3}, {211, 2}, {111, 1}, {16, 1}};
const map<PdgId, unsigned int> mode2CC = {{211, 3}, {-211, 2}, {111, 1}, {-16, 1}};
/// @}

};

RIVET_DECLARE_PLUGIN(CLEO_2001_I535016);

} ```