Rivet analyses

title: TASSO_1990_I284251

$K^0,\bar{K}^0$ and $K^{*\pm}$ spectra in $e^+e^-$ collisions for centre-of-mass energies between 14.8 and 42.6 GeV

Experiment: TASSO (Petra)

Inspire ID: 284251

Status: VALIDATED

Authors: - Peter Richardson

References: - Z.Phys. C47 (1990) 167-180, 1990

Beams: e+ e-

Beam energies: (7.4, 7.4); (10.8, 10.8); (17.2, 17.2); (17.5, 17.5); (21.3, 21.3)GeV

Run details: - e+ e- to hadrons.

Measurement of the $K^0,\bar{K}^0$ and $K^{*\pm}$ spectra in $e^+e^-$ collisions for centre-of-mass energies between 14.8 and 42.6 GeV by the TASSO experiment at Petra.

Source code:TASSO_1990_I284251.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/Sphericity.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief K0 and K*+ spectra class TASSO_1990_I284251 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(TASSO_1990_I284251);


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

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

  // Initialise and register projections
  declare(Beam(), "Beams");
  declare(UnstableParticles(), "UFS");
  const ChargedFinalState cfs;
  declare(cfs, "CFS");
  declare(Sphericity(cfs), "Sphericity");


  // Book histograms
  _isqs = 10;
  size_t i = 0;
  for (double eVal : allowedEnergies()) {

    const string en = toString(round(eVal / MeV));
    if (isCompatibleWithSqrtS(eVal)) {
      _sqs = en;
      _isqs = i;
    }

    size_t _ih, _iy;
    if (i == 0) {
      _ih = 1;
      _iy = 0;
    }
    else if (i == 1) {
      _ih = 2;
      _iy = 0;
    }
    else if (i == 2) {
      _ih = 0;
      _iy = 3;
    }
    else if (i == 3) {
      _ih = 0;
      _iy = 2;
    }
    else {
      _ih = 0;
      _iy = 1;
    }

    if (_ih == 0) {
      book(_h[en + "K0_x"], 1, 1, _iy);
      if (_iy != 3) {
        book(_p_K0_S_1[i], 5, 1, 2 * _iy - 1);
        book(_p_K0_S_2[i], "TMP/p_K0_S_2_" + to_string(i), refData(5, 1, 2 * _iy));
      }
      book(_h[en + "Kstar_x"], 8, 1, _iy);
      if (_iy == 2) {
        book(_p_Kstar_S_1, 10, 1, 1);
        book(_p_Kstar_S_2, "TMP/p_Kstar_S_2", refData(10, 1, 2));
      }
    }
    else {
      book(_h[en + "K0_x"], _ih + 1, 1, 1);
      book(_p_K0_S_1[i], _ih + 5, 1, 1);
      book(_p_K0_S_2[i], "TMP/p_K0_S_2" + to_string(i), refData(_ih + 5, 1, 2));
    }
    ++i;
  }
  raiseBeamErrorIf(_isqs == 10);
  book(_n_K0, 4, 1, 1);
  book(_n_Kstar, 9, 1, 1);
}


/// 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");

  // Get beams and average beam momentum
  const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
  const double meanBeamMom = (beams.first.p3().mod() + beams.second.p3().mod()) / 2.0;
  const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");

  unsigned int nK0(0), nKstar(0);
  UnstableParticles ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles(Cuts::abspid == 323 or Cuts::pid == 130 or Cuts::pid == 310)) {
    double xE = p.E() / meanBeamMom;
    double modp = p.p3().mod();
    double beta = modp / p.E();
    if (p.abspid() == 323) {
      if (_isqs > 1) _h[_sqs + "Kstar_x"]->fill(xE, 1. / beta);
      ++nKstar;
    }
    else {
      _h[_sqs + "K0_x"]->fill(xE, 1. / beta);
      ++nK0;
    }
  }
  _n_K0->fill(_dedges[_isqs], nK0);
  _n_Kstar->fill(_dedges[_isqs], nKstar);
  const double sphere = sphericity.sphericity();
  if (_isqs != 2) {
    _p_K0_S_1[_isqs]->fill(sphere, nK0);
    _p_K0_S_2[_isqs]->fill(sphere, cfs.particles().size());
  }
  if (_isqs == 3) {
    _p_Kstar_S_1->fill(sphere, nKstar);
    _p_Kstar_S_2->fill(sphere, cfs.particles().size());
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  const double sf = crossSection() / sumOfWeights();
  for (auto& item : _h) {
    const double en = stod(item.first.substr(0, 5)) * MeV;
    if (item.first.find("K0_x") != string::npos) {
      scale(item.second, sqr(en) * sf / microbarn);
    }
    else {
      scale(item.second, sqr(en) * sf / nanobarn);
    }
  }

  size_t i = 0;
  for (double eVal : allowedEnergies()) {
    (void)eVal;

    size_t _ih, _iy;
    if (i == 0) {
      _ih = 1;
      _iy = 0;
    }
    else if (i == 1) {
      _ih = 2;
      _iy = 0;
    }
    else if (i == 2) {
      _ih = 0;
      _iy = 3;
    }
    else if (i == 3) {
      _ih = 0;
      _iy = 2;
    }
    else {
      _ih = 0;
      _iy = 1;
    }

    if (_iy != 3) {
      Estimate1DPtr temp;
      if (_ih == 0)
        book(temp, 5, 1, 2 * _iy);
      else
        book(temp, _ih + 5, 1, 2);
      divide(_p_K0_S_1[i], _p_K0_S_2[i], temp);
    }
    if (i == 3) {
      Estimate1DPtr temp;
      book(temp, 10, 1, 2);
      divide(_p_Kstar_S_1, _p_Kstar_S_2, temp);
    }
    ++i;
  }
}

/// @}


/// @name Histograms
/// @{
map<string, Histo1DPtr> _h;

Profile1DPtr _p_K0_S_1[5], _p_K0_S_2[5], _p_Kstar_S_1, _p_Kstar_S_2;

BinnedProfilePtr<string> _n_K0, _n_Kstar;

vector<string> _dedges{"14.8"s, "21.5"s, "34.5"s, "35.0"s, "42.6"s};

size_t _isqs;

string _sqs = "";
/// @}

};

RIVET_DECLARE_PLUGIN(TASSO_1990_I284251);

} ```