Rivet analyses

title: TASSO_1980_I153656

$\pi^\pm$, $K^\pm$ and $p,\bar{p}$ spectra in $e^+e^-$ at 12 and 30 GeV

Experiment: TASSO (Petra)

Inspire ID: 153656

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B94 (1980) 444-449, 1980

Beams: e+ e-

Beam energies: (6.0, 6.0); (15.0, 15.0)GeV

Run details: - e+ e- to hadrons.

Measurement of the $\pi^\pm$, $K^\pm$ and $p,\bar{p}$ spectra in $e^+e^-$ collisions for centre-of-mass energies of 12 and 30 GeV by the TASSO experiment at Petra.

Source code:TASSO_1980_I153656.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/ChargedFinalState.hh"

namespace Rivet {

/// @brief pi, K and proton spectra at 12 and 30 GeV class TASSO_1980_I153656 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1980_I153656);


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

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

  // Initialise and register projections
  declare(Beam(), "Beams");
  declare(ChargedFinalState(), "FS");

  // Book histograms
  size_t ih = 0;
  for (double eVal : allowedEnergies()) {
    const string en = toString(round(eVal));
    if (isCompatibleWithSqrtS(eVal)) _sqs = en;

    book(_h[en + "pi"], 3 * ih + 2, 1, 1);
    book(_h[en + "K"], 3 * ih + 3, 1, 1);
    book(_h[en + "p"], 3 * ih + 4, 1, 1);

    tribook(en + "pi", 3 * ih + 8, 1, 1);
    tribook(en + "K", 3 * ih + 9, 1, 1);
    tribook(en + "p", 3 * ih + 10, 1, 1);

    if (ih) {
      _axes[en + "pi"] = YODA::Axis<double>({0.325, 0.375, 0.425, 0.5, 0.575, 0.7, 0.9, 1.1, 1.3, 1.5});
      _axes[en + "K"] = YODA::Axis<double>({0.4, 0.5, 0.575, 0.7, 0.9, 1.1});
      _axes[en + "p"] = YODA::Axis<double>({0.5, 0.7, 1.2325, 2.0975});
      _axes[en + "r"] = YODA::Axis<double>({0.4, 0.5, 0.575, 0.7, 0.9, 1.1});
    }
    else {
      _axes[en + "pi"] = YODA::Axis<double>({0.3, 0.4, 0.5, 0.6, 1.0, 1.6});
      _axes[en + "K"] = YODA::Axis<double>({0.4, 0.5, 0.6, 1.0});
      _axes[en + "p"] = YODA::Axis<double>({0.5, 0.7, 0.9, 2.43});
      _axes[en + "r"] = YODA::Axis<double>({0.4, 0.5, 0.6, 1.0});
    }
    ++ih;
  }
  raiseBeamErrorIf(_sqs.empty());
  _axes["rp"] = YODA::Axis<double>({0.475, 0.725, 1.0, 2.2});
}

void tribook(const string& label, unsigned int d, unsigned int x, unsigned int y) {
  book(_nd["n_" + label], "TMP/n_" + label, refData<YODA::BinnedEstimate<string>>(d, x, y));
  book(_nd["d_" + label], "TMP/d_" + label, refData<YODA::BinnedEstimate<string>>(d, x, y));
  book(_r[label], d, x, y);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) {
    for (const auto& item : _h) {
      _edges[item.first] = item.second->xEdges();
    }
    for (const auto& item : _r) {
      _edges["r" + item.first] = _nd["n_" + item.first]->xEdges();
    }
  }
  // First, veto on leptonic events by requiring at least 4 charged FS particles
  const ChargedFinalState& fs = apply<ChargedFinalState>(event, "FS");
  const size_t numParticles = fs.particles().size();

  // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
  if (numParticles < 2) vetoEvent;

  // Get beams and average beam momentum
  const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
  const double meanBeamMom = 0.5 * (beams.first.p3().mod() + beams.second.p3().mod());
  MSG_DEBUG("Avg beam momentum = " << meanBeamMom);

  for (const Particle& p : fs.particles()) {
    double modp = p.p3().mod();
    fillND("d_" + _sqs + "pi", modp);
    fillND("d_" + _sqs + "K", modp);
    fillND("d_" + _sqs + "p", modp);
    if (p.abspid() == 211) {
      fillhist(_sqs + "pi", modp);
      fillND("n_" + _sqs + "pi", modp);
    }
    else if (p.abspid() == 321) {
      fillhist(_sqs + "K", modp);
      fillND("n_" + _sqs + "K", modp);
    }
    else if (p.abspid() == 2212) {
      fillhist(_sqs + "p", modp);
      fillND("n_" + _sqs + "p", modp);
    }
  }
}

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

void fillND(const string& label, const double value) {
  string edge = "OTHER";
  const string tag = label.substr(2);
  const string en = tag.substr(0, 2);
  const size_t idx = _axes[(tag.substr(2) == "p") ? "rp" : en + "r"].index(value);
  if (idx && idx <= _edges["r" + tag].size()) edge = _edges["r" + tag][idx - 1];
  _nd[label]->fill(edge);
}

/// Normalise histograms etc., after the run
void finalize() {
  scale(_h, crossSection() / nanobarn / sumOfWeights());
  for (auto& item : _h) {
    for (auto& b : item.second->bins()) {
      b.scaleW(1. / _axes[item.first].width(b.index()));
    }
  }
  for (auto& item : _r) {
    divide(_nd["n_" + item.first], _nd["d_" + item.first], item.second);
  }
}

/// @}


/// @name Histograms
/// @{
map<string, BinnedHistoPtr<string>> _h, _nd;
map<string, BinnedEstimatePtr<string>> _r;
map<string, YODA::Axis<double>> _axes;
map<string, vector<string>> _edges;
string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(TASSO_1980_I153656); } ```