Rivet analyses

title: CLEO_2004_I645209

Charm hadrons from fragmentation near the $\Upsilon(4S)$

Experiment: CLEO (CESR)

Inspire ID: 645209

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev.D70:112001,2004. - arXiv: hep-ex/0402040

Beams: e+ e-

Beam energies: (5.3, 5.3)GeV

Run details: - $e^+ e^-$ analysis near the $\Upsilon(4S)$ resonance

Analysis of charm quark fragmentation at 10.5 GeV, based on a data sample of 103 fb collected by the CLEO experiment. Fragmentation into charm is studied for the charmed hadron ground states, namely $D^0$, $D^+$, as well as the excited states $D^{0}$ and $D^{+}$. This analysis can be used to constrain charm fragmentation in Monte Carlo generators.

Source code:CLEO_2004_I645209.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief CLEO charmed mesons and baryons from fragmentation /// /// @author Peter Richardson class CLEO_2004_I645209 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(CLEO_2004_I645209);

void init() {
  declare(Beam(), "Beams");
  declare(UnstableParticles(), "UFS");

  // continuum cross sections
  book(_sigmaDPlus, 1, 1, 1);
  book(_sigmaD0A, 1, 1, 2);
  book(_sigmaD0B, 1, 1, 3);
  book(_sigmaDStarPlusA, 1, 1, 4);
  book(_sigmaDStarPlusB, 1, 1, 5);
  book(_sigmaDStar0A, 1, 1, 6);
  book(_sigmaDStar0B, 1, 1, 7);

  // histograms for continuum data
  book(_histXpDplus, 2, 1, 1);
  book(_histXpD0A, 3, 1, 1);
  book(_histXpD0B, 4, 1, 1);
  book(_histXpDStarPlusA, 5, 1, 1);
  book(_histXpDStarPlusB, 6, 1, 1);
  book(_histXpDStar0A, 7, 1, 1);
  book(_histXpDStar0B, 8, 1, 1);
  book(_histXpTotal, 9, 1, 1);
}


void analyze(const Event& e) {
  // Loop through unstable FS particles and look for charmed mesons/baryons
  const UnstableParticles& ufs = apply<UnstableParticles>(e, "UFS");

  const Beam beamproj = apply<Beam>(e, "Beams");
  const ParticlePair& beams = beamproj.beams();
  const FourMomentum mom_tot = beams.first.momentum() + beams.second.momentum();
  LorentzTransform cms_boost;
  if (mom_tot.p3().mod() > 1 * MeV)
    cms_boost = LorentzTransform::mkFrameTransformFromBeta(mom_tot.betaVec());
  const double s = sqr(beamproj.sqrtS());

  // Particle masses from PDGlive (accessed online 16. Nov. 2009).
  for (const Particle& p : ufs.particles()) {

    double xp = 0.0;
    double mH2 = 0.0;
    // 3-momentum in CMS frame
    const double mom = cms_boost.transform(p.momentum()).vector3().mod();

    const int pdgid = p.abspid();
    MSG_DEBUG("pdgID = " << pdgid << "  mom = " << mom);
    switch (pdgid) {

      case 421:
        MSG_DEBUG("D0 found");
        mH2 = 3.47763; // 1.86484^2
        xp = mom / sqrt(s / 4.0 - mH2);
        _sigmaD0A->fill(Ecm);
        _sigmaD0B->fill(Ecm);
        _histXpD0A->fill(xp);
        _histXpD0B->fill(xp);
        _histXpTotal->fill(xp);
        break;

      case 411:
        MSG_DEBUG("D+ found");
        mH2 = 3.49547; // 1.86962^2
        xp = mom / sqrt(s / 4.0 - mH2);
        _sigmaDPlus->fill(Ecm);
        _histXpDplus->fill(xp);
        _histXpTotal->fill(xp);
        break;

      case 413:
        MSG_DEBUG("D*+ found");
        mH2 = 4.04119; // 2.01027^2
        xp = mom / sqrt(s / 4.0 - mH2);
        _sigmaDStarPlusA->fill(Ecm);
        _sigmaDStarPlusB->fill(Ecm);
        _histXpDStarPlusA->fill(xp);
        _histXpDStarPlusB->fill(xp);
        _histXpTotal->fill(xp);
        break;

      case 423:
        MSG_DEBUG("D*0 found");
        mH2 = 4.02793; // 2.00697**2
        xp = mom / sqrt(s / 4.0 - mH2);
        _sigmaDStar0A->fill(Ecm);
        _sigmaDStar0B->fill(Ecm);
        _histXpDStar0A->fill(xp);
        _histXpDStar0B->fill(xp);
        _histXpTotal->fill(xp);
        break;
    }
  }
}


void finalize() {

  const double sf = crossSection() / picobarn / sumOfWeights();
  scale(_sigmaDPlus, sf);
  scale(_sigmaD0A, sf);
  scale(_sigmaD0B, sf);
  scale(_sigmaDStarPlusA, sf);
  scale(_sigmaDStarPlusB, sf);
  scale(_sigmaDStar0A, sf);
  scale(_sigmaDStar0B, sf);

  scale(_histXpDplus, sf);
  scale(_histXpD0A, sf);
  scale(_histXpD0B, sf);
  scale(_histXpDStarPlusA, sf);
  scale(_histXpDStarPlusB, sf);
  scale(_histXpDStar0A, sf);
  scale(_histXpDStar0B, sf);
  scale(_histXpTotal, sf / 4.);
}

private:

// Histograms for the continuum cross sections
BinnedHistoPtr<string> _sigmaDPlus;
BinnedHistoPtr<string> _sigmaD0A;
BinnedHistoPtr<string> _sigmaD0B;
BinnedHistoPtr<string> _sigmaDStarPlusA;
BinnedHistoPtr<string> _sigmaDStarPlusB;
BinnedHistoPtr<string> _sigmaDStar0A;
BinnedHistoPtr<string> _sigmaDStar0B;

// Histograms for continuum data
Histo1DPtr _histXpDplus;
Histo1DPtr _histXpD0A;
Histo1DPtr _histXpD0B;
Histo1DPtr _histXpDStarPlusA;
Histo1DPtr _histXpDStarPlusB;
Histo1DPtr _histXpDStar0A;
Histo1DPtr _histXpDStar0B;
Histo1DPtr _histXpTotal;
const string Ecm = "10.56";

};

RIVET_DECLARE_ALIASED_PLUGIN(CLEO_2004_I645209, CLEO_2004_S5809304);

} ```

Aliases: - CLEO_2004_S5809304