Rivet analyses

title: HRS_1987_I246162

$\Sigma^{*\pm}$ and $\Xi^-$ spectra at 29 GeV

Experiment: HRS (PEP)

Inspire ID: 246162

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 58 (1987) 2627

Beams: e+ e-

Beam energies: (14.5, 14.5)GeV

Run details: - e+ e- -> hadrons

Measurement of the $\Sigma^{*\pm}$ and $\Xi^-$ spectra at 29 GeV

Source code:HRS_1987_I246162.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Xi- and Sigma*+/- spectra class HRS_1987_I246162 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(HRS_1987_I246162);


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

/// Book histograms and initialise projections before the run
void init() {
  // projects
  declare(UnstableParticles(Cuts::abspid == 3114 || Cuts::abspid == 3224 || Cuts::abspid == 3312
                            || Cuts::abspid == 3122),
          "UFS");
  const ChargedFinalState cfs;
  declare(cfs, "CFS");
  // histos
  for (unsigned int ix = 0; ix < 2; ++ix) {
    for (unsigned int iy = 0; iy < 2; ++iy) book(_h_total[ix][iy], 1 + ix, 1, 1 + iy);
    book(_h_x[ix], 4, 1, 1 + ix);
    book(_h_ratio[ix], 3, 1, 1 + ix);
  }
  book(_c, "TMP/nLam");
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
  const size_t numParticles = cfs.particles().size();

  // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
  if (numParticles < 2) {
    MSG_DEBUG("Failed leptonic event cut");
    vetoEvent;
  }
  MSG_DEBUG("Passed leptonic event cut");
  for (const Particle& p : apply<UnstableParticles>(event, "UFS").particles()) {
    if (p.abspid() == 3122) {
      _c->fill();
      continue;
    }
    double xE = 2. * p.E() / sqrtS();
    Vector3 mom3 = p.p3();
    const double energy = p.E();
    double modp = mom3.mod();
    double beta = modp / energy;
    unsigned int iloc = p.abspid() == 3312 ? 1 : 0;
    _h_ratio[iloc]->fill(29);
    if (iloc == 0 && xE > 0.1 && xE < 0.8)
      _h_total[iloc][0]->fill(29);
    else if (iloc == 1 && xE > 0.05 && xE < 0.75)
      _h_total[iloc][0]->fill(29);
    _h_total[iloc][1]->fill(29);
    _h_x[iloc]->fill(xE, 1. / beta);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  for (unsigned int ix = 0; ix < 2; ++ix) {
    scale(_h_total[ix], 1. / sumOfWeights());
    scale(_h_x[ix], sqr(sqrtS()) * crossSection() / nanobarn / sumOfWeights());
    scale(_h_ratio[ix], 1. / *_c);
  }
}

/// @}


/// @name Histograms
/// @{
BinnedHistoPtr<int> _h_total[2][2], _h_ratio[2];
Histo1DPtr _h_x[2];
CounterPtr _c;
/// @}

};

RIVET_DECLARE_PLUGIN(HRS_1987_I246162);

} ```