Rivet analyses

title: BABAR_2013_I1238276

Production of charged pions, kaons, and protons in $e^+e^-$ annihilations into hadrons at $\sqrt{s}=10.54$GeV

Experiment: BaBar (PEP-II)

Inspire ID: 1238276

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Rev. D88 (2013) 3, 032011 - arXiv: 1306.2895 - DOI: 10.1103/PhysRevD.88.032011

Beams: e+ e-

Beam energies: (3.5, 8.0)GeV

Run details: - $e^+ e^-$ analysis in the continuum near the $\Upsilon(4S)$ resonance, with CoM boosts of 8.0~GeV~($e^-$) and 3.5~GeV~($e^+$)

Measurement of charged pion, kaon and proton production in $e^+e^-$ collisions with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass energy of 10.54 GeV. This is a measurement in the continuum.

Source code:BABAR_2013_I1238276.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/Beam.hh"

include "Rivet/Projections/ChargedFinalState.hh"

namespace Rivet {

/// @brief BaBar pion, kaon and proton production in the continuum /// @author Peter Richardson class BABAR_2013_I1238276 : public Analysis { public:

BABAR_2013_I1238276()
    : Analysis("BABAR_2013_I1238276") { }


void init() {
  declare(Beam(), "Beams");
  declare(ChargedFinalState(), "FS");

  book(_histPion_no_dec, 1, 1, 1);
  book(_histKaon_no_dec, 1, 1, 2);
  book(_histProton_no_dec, 1, 1, 3);
  book(_histPion_dec, 2, 1, 1);
  book(_histKaon_dec, 2, 1, 2);
  book(_histProton_dec, 2, 1, 3);
}


void analyze(const Event& e) {
  // Loop through charged FS particles and look for charmed mesons/baryons
  const ChargedFinalState& fs = apply<ChargedFinalState>(e, "FS");

  const Beam beamproj = apply<Beam>(e, "Beams");
  const ParticlePair& beams = beamproj.beams();
  const FourMomentum mom_tot = beams.first.momentum() + beams.second.momentum();
  const LorentzTransform cms_boost = LorentzTransform::mkFrameTransformFromBeta(mom_tot.betaVec());
  MSG_DEBUG("CMS Energy sqrt s = " << beamproj.sqrtS());

  for (const Particle& p : fs.particles()) {
    // check if prompt or not
    ConstGenParticlePtr pmother = p.genParticle();
    ConstGenVertexPtr ivertex = pmother->production_vertex();
    bool prompt = true;
    while (ivertex) {
      vector<ConstGenParticlePtr> inparts = HepMCUtils::particles(ivertex, Relatives::PARENTS);
      int n_inparts = inparts.size();
      if (n_inparts < 1) break;
      pmother = inparts[0]; // first mother particle
      int mother_pid = abs(pmother->pdg_id());
      if (mother_pid == PID::K0S || mother_pid == PID::LAMBDA) {
        prompt = false;
        break;
      }
      else if (mother_pid < 6) {
        break;
      }
      ivertex = pmother->production_vertex();
    }

    // momentum in CMS frame
    const double mom = cms_boost.transform(p.momentum()).vector3().mod();
    const int PdgId = p.abspid();
    MSG_DEBUG("pdgID = " << PdgId << " Momentum = " << mom);
    switch (PdgId) {
      case PID::PIPLUS:
        if (prompt) _histPion_no_dec->fill(mom);
        _histPion_dec->fill(mom);
        break;
      case PID::KPLUS:
        if (prompt) _histKaon_no_dec->fill(mom);
        _histKaon_dec->fill(mom);
        break;
      case PID::PROTON:
        if (prompt) _histProton_no_dec->fill(mom);
        _histProton_dec->fill(mom);
      default: break;
    }
  }
}


void finalize() {
  scale(_histPion_no_dec, 1. / sumOfWeights());
  scale(_histKaon_no_dec, 1. / sumOfWeights());
  scale(_histProton_no_dec, 1. / sumOfWeights());
  scale(_histPion_dec, 1. / sumOfWeights());
  scale(_histKaon_dec, 1. / sumOfWeights());
  scale(_histProton_dec, 1. / sumOfWeights());
}

private:

/// @{
// Histograms for continuum data (sqrt(s) = 10.52 GeV)
// no K_S and Lambda decays
Histo1DPtr _histPion_no_dec;
Histo1DPtr _histKaon_no_dec;
Histo1DPtr _histProton_no_dec;
// including decays
Histo1DPtr _histPion_dec;
Histo1DPtr _histKaon_dec;
Histo1DPtr _histProton_dec;
/// @}

};

RIVET_DECLARE_PLUGIN(BABAR_2013_I1238276);

} ```