Rivet analyses

title: ARGUS_1993_I357132

Spectrum for $\Lambda_c^+(2625)$ production at 10.58 GeV

Experiment: ARGUS (DORIS)

Inspire ID: 357132

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett. B317 (1993) 227-232

Beams: e+ e-

Beam energies: (5.3, 5.3)GeV

Run details: - e+e- to hadrons

Spectrum for $\Lambda_c^+(2625)$ production at 10.58 GeV measured by ARGUS.

Source code:ARGUS_1993_I357132.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Spectrum for Lambda_c(2625) class ARGUS_1993_I357132 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ARGUS_1993_I357132);


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

/// Book histograms and initialise projections before the run
void init() {
  // projections
  declare(Beam(), "Beams");
  declare(UnstableParticles(), "UFS");
  // book histos
  book(_h_rate, 1, 1, 1);
  book(_h_x, 2, 1, 1);
}

void findDecayProducts(Particle parent, Particles& Lambda_c, Particles& pions, unsigned int& nstable) {
  for (const Particle& p : parent.children()) {
    if (p.abspid() == 4122) {
      Lambda_c.push_back(p);
      ++nstable;
    }
    else if (p.abspid() == PID::PIPLUS) {
      pions.push_back(p);
      ++nstable;
    }
    else if (!p.children().empty())
      findDecayProducts(p, Lambda_c, pions, nstable);
    else
      ++nstable;
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  static const int id2625 = 102144;
  // Get beams and average beam momentum
  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(2.625));
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles(Cuts::abspid == id2625)) {
    double xp = p.momentum().p3().mod() / Pmax;
    _h_x->fill(xp);
    Particles Lambda_c, pions;
    unsigned int nstable(0);
    findDecayProducts(p, Lambda_c, pions, nstable);
    if (nstable == 3 && pions.size() == 2 && Lambda_c.size() == 1) _h_rate->fill("10.58"s);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  normalize(_h_x);
  scale(_h_rate, crossSection() / picobarn / sumOfWeights());
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_x;
BinnedHistoPtr<string> _h_rate;
/// @}

};

RIVET_DECLARE_PLUGIN(ARGUS_1993_I357132);

} ```