Rivet analyses

title: HRS_1986_I18688

$f_2(1270)$, $f_0(980)$ and $K_2(1430)^0$ spectra at 29 GeV

Experiment: HRS (HRS)

Inspire ID: 18688

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.Lett. 57 (1986) 1990

Beams: e+ e-

Beam energies: (14.5, 14.5)GeV

Run details: none listed

Measurement of the $f_2(1270)$, $f_0(980)$ and $K_2(1430)^0$ spectra at 29 GeV by the HRS experiment.

Source code:HRS_1986_I18688.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief f_2, f_0 and K_2 spectra at 29 GeV class HRS_1986_I18688 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(HRS_1986_I18688);

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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(), "UFS");
  book(_h_f2, 1, 1, 1);
  book(_h_f0, 1, 1, 2);
  book(_h_K2, 1, 1, 3);
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  if (_edges.empty()) _edges = _h_f2->xEdges();
  UnstableParticles ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p :
       ufs.particles(Cuts::abspid == 9010221 || Cuts::abspid == 225 || Cuts::abspid == 315)) {
    Vector3 mom3 = p.p3();
    const double energy = p.E();
    double modp = mom3.mod();
    double beta = modp / energy;
    double xE = 2. * modp / sqrtS();
    if (p.pid() == 225) {
      _h_f2->fill(map2string(xE), 1. / beta);
    }
    else if (p.pid() == 315) {
      _h_K2->fill(map2string(xE), 1. / beta);
    }
    else {
      _h_f0->fill(map2string(xE), 1. / beta);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  scale(_h_f0, sqr(sqrtS()) * crossSection() / nanobarn / sumOfWeights());
  scale(_h_f2, sqr(sqrtS()) * crossSection() / nanobarn / sumOfWeights());
  scale(_h_K2, sqr(sqrtS()) * crossSection() / nanobarn / sumOfWeights());
  for (auto& hist : {_h_f0, _h_f2, _h_K2}) {
    for (auto& b : hist->bins()) {
      const size_t idx = b.index();
      b.scaleW(1. / _axis.width(idx));
    }
  }
}

///@}

string map2string(const double value) const {
  const size_t idx = _axis.index(value);
  if (idx && idx <= _edges.size()) return _edges[idx - 1];
  return "OTHER";
}

/// @name Histograms
///@{
BinnedHistoPtr<string> _h_f0, _h_f2, _h_K2;
YODA::Axis<double> _axis{0.1, 0.2, 0.3, 0.4, 0.7};
vector<string> _edges;
///@}

};

RIVET_DECLARE_PLUGIN(HRS_1986_I18688);

} ```