Rivet analyses

title: ARGUS_1990_I296522

Spectrum for $\Xi_c^{0,+}$ production at 10.5 GeV

Experiment: ARGUS (DORIS)

Inspire ID: 296522

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B247 (1990) 121-126

Beams: e+ e-

Beam energies: (5.2, 5.2)GeV

Run details: - e+e- to hadrons

Spectrum for $\Xi_c^{0,+}$ production at 10.58 GeV measured by ARGUS.

Source code:ARGUS_1990_I296522.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Xi_c+ spectrum class ARGUS_1990_I296522 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1990_I296522);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  declare(Beam(), "Beams");
  declare(UnstableParticles(), "UFS");
  // book histos
  book(_h_obs1, 1, 1, 1);
  book(_h_obs2, 1, 1, 2);
  book(_h_obs3, 1, 1, 3);
  book(_h_all1, 2, 1, 1);
  book(_h_all2, 2, 1, 2);
  book(_h_all3, 2, 1, 3);
  book(_h_x, 3, 1, 1);
}

void findDecayProducts(Particle parent, Particles& Xi, Particles& pions, unsigned int& nstable) {
  for (const Particle& p : parent.children()) {
    if (p.abspid() == PID::XIMINUS) {
      Xi.push_back(p);
      ++nstable;
    }
    else if (p.abspid() == PID::PIPLUS) {
      pions.push_back(p);
      ++nstable;
    }
    else if (!p.children().empty())
      findDecayProducts(p, Xi, pions, nstable);
    else
      ++nstable;
  }
}

/// Perform the per-event analysis
void analyze(const Event& event) {
  static const int idXip = 4232, idXi0 = 4132;
  const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
  const double Emax = (beams.first.p3().mod() + beams.second.p3().mod()) / 2.0;
  const double Pmax = sqrt(sqr(Emax) - sqr(2.468));
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles(Cuts::abspid == idXip or Cuts::abspid == idXi0)) {
    double xp = p.momentum().p3().mod() / Pmax;
    _h_x->fill(xp);
    Particles Xi, pions;
    unsigned int nstable(0);
    findDecayProducts(p, Xi, pions, nstable);
    if (nstable == 2 && Xi.size() == 1 && pions.size() == 1) {
      _h_obs1->fill(xp);
      _h_all1->fill(xp);
    }
    else if (nstable == 3 && Xi.size() == 1 && pions.size() == 2) {
      _h_obs3->fill(xp);
      _h_all3->fill(xp);
    }
    else if (nstable == 4 && Xi.size() == 1 && pions.size() == 3) {
      _h_obs2->fill(xp);
      _h_all2->fill(xp);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h_x);
  scale(_h_obs1, 0.5 * crossSection() / picobarn / sumOfWeights());
  scale(_h_obs2, 0.5 * crossSection() / picobarn / sumOfWeights());
  scale(_h_obs3, 0.5 * crossSection() / picobarn / sumOfWeights());
  scale(_h_all1, crossSection() / picobarn / sumOfWeights());
  scale(_h_all2, crossSection() / picobarn / sumOfWeights());
  scale(_h_all3, crossSection() / picobarn / sumOfWeights());
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_obs1, _h_obs2, _h_obs3, _h_all1, _h_all2, _h_all3;
Histo1DPtr _h_x;
/// @}

};

RIVET_DECLARE_PLUGIN(ARGUS_1990_I296522);

} ```