Rivet analyses

title: HRS_1987_I215848

Hadron Spectra in $e^+e^-$ collisions at 29 GeV

Experiment: HRS (PEP)

Inspire ID: 215848

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D 35 (1987) 2639

Beams: e+ e-

Beam energies: (14.5, 14.5)GeV

Run details: - Hadronic e+e- events at $\sqrt{s} = 29.$ GeV

$K^0$, $K^+$, $p$, $\pi^+$ and $\Lambda^0$ spectra at $\sqrt{s} = 29.$ GeV using the HRS detector at PEP.

Source code:HRS_1987_I215848.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Hadron Spectra in $e^+e^-$ collisions at 29 GeV class HRS_1987_I215848 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(HRS_1987_I215848);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(), "UFS");
  // hists
  book(_d["pi"], 2, 1, 1);
  book(_d["Kp"], 3, 1, 1);
  book(_d["p"], 4, 1, 1);
  book(_h["K0"], 5, 1, 1);
  book(_h["lam"], 6, 1, 1);
  _axes["pi"] = YODA::Axis<double>({0.035800994999999995, 0.049226100999999994, 0.06281088, 0.076470283,
                                    0.090170398, 0.103895139, 0.11763585, 0.13138755});
  _axes["Kp"] = YODA::Axis<double>({0.048458616, 0.059073984, 0.070793603, 0.083151849, 0.095902214,
                                    0.108906933, 0.122084929, 0.135385471});
  _axes["p"] = YODA::Axis<double>({0.073322849, 0.08073250800000001, 0.08966457400000001, 0.099710693,
                                   0.110567797, 0.122019328, 0.133913114, 0.14614108599999998});
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) {
    for (const auto& item : _d) {
      _edges[item.first] = item.second->xEdges();
    }
  }
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles()) {
    const double xE = 2. * p.E() / sqrtS();
    const double beta = p.p3().mod() / p.E();
    if (p.pid() == 130 || p.pid() == 310) {
      _h["K0"]->fill(xE, 1. / beta);
    }
    else if (p.abspid() == 321) {
      discfill("Kp", xE, 1. / beta);
    }
    else if (p.abspid() == 211) {
      discfill("pi", xE, 1. / beta);
    }
    else if (p.abspid() == 2212) {
      discfill("p", xE, 1. / beta);
    }
    else if (p.abspid() == 3122) {
      _h["lam"]->fill(xE, 1. / beta);
    }
  }
}

void discfill(const string& name, const double value, const double weight) {
  string edge = "OTHER";
  const size_t idx = _axes[name].index(value);
  if (idx && idx <= _edges[name].size()) edge = _edges[name][idx - 1];
  _d[name]->fill(edge, weight);
}

/// Normalise histograms etc., after the run
void finalize() {
  const double sf = crossSection() * sqr(sqrtS()) / microbarn / sumOfWeights();
  scale(_h, sf);
  scale(_d, sf);
  for (auto& hist : _d) {
    for (auto& b : hist.second->bins()) {
      const size_t idx = b.index();
      b.scaleW(1. / _axes[hist.first].width(idx));
    }
  }
}

///@}


/// @name Histograms
///@{
map<string, Histo1DPtr> _h;
map<string, BinnedHistoPtr<string>> _d;
map<string, YODA::Axis<double>> _axes;
map<string, vector<string>> _edges;
///@}

};

RIVET_DECLARE_PLUGIN(HRS_1987_I215848);

} ```