Rivet analyses

title: CMS_2012_PAS_QCD_11_010

Strange particle production in underlying events in proton--proton collisions at $\sqrt{s} = 7$ TeV

Experiment: CMS (LHC)

Inspire ID: 1260780

Status: PRELIMINARY

Authors: - Sercan Sen

References: - Expt page: CMS-PAS-QCD-11-010 - http://cdsweb.cern.ch/record/1463352

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - Inelastic events (non-diffractive and inelastic diffractive) at $\sqrt{s} = 7$~TeV.

Measurements of the production of $K^0_S$, $\Lambda$ and $\bar{\Lambda}$ particles in the underlying activity of events with a $\pT$ scale ranging from 1 to 50 GeV/$c$ in $pp$ collisions at $\sqrt{s} = 7$~TeV.

Source code:CMS_2012_PAS_QCD_11_010.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/ChargedFinalState.hh"

include "Rivet/Projections/FastJets.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

class CMS_2012_PAS_QCD_11_010 : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_PAS_QCD_11_010);

void init() {
  const FastJets jets(ChargedFinalState(Cuts::abseta < 2.5 && Cuts::pT > 0.5 * GeV), JetAlg::ANTIKT, 0.5);
  declare(jets, "Jets");

  const UnstableParticles ufs(Cuts::abseta < 2 && Cuts::pT > 0.6 * GeV);
  declare(ufs, "UFS");

  book(_h_nTrans_Lambda, 1, 1, 1);
  book(_h_nTrans_Kaon, 2, 1, 1);
  book(_h_ptsumTrans_Lambda, 3, 1, 1);
  book(_h_ptsumTrans_Kaon, 4, 1, 1);
}


void analyze(const Event& event) {

  Jets jets = apply<FastJets>(event, "Jets").jetsByPt(Cuts::pT > 1.0 * GeV);
  if (jets.size() < 1) vetoEvent;

  if (fabs(jets[0].eta()) >= 2) { // cuts on leading jets
    vetoEvent;
  }

  FourMomentum p_lead = jets[0].momentum();
  const double pTlead = p_lead.pT();

  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");

  int numTrans_Kaon = 0;
  int numTrans_Lambda = 0;
  double ptSumTrans_Kaon = 0.;
  double ptSumTrans_Lambda = 0.;

  for (const Particle& p : ufs.particles()) {
    double dphi = deltaPhi(p, p_lead);
    double pT = p.pT();
    const PdgId id = p.abspid();

    if (dphi > PI / 3. && dphi < 2. / 3. * PI) {
      if (id == 310 && pT > 0.6 * GeV) {
        ptSumTrans_Kaon += pT / GeV;
        numTrans_Kaon++;
      }
      else if (id == 3122 && pT > 1.5 * GeV) {
        ptSumTrans_Lambda += pT / GeV;
        numTrans_Lambda++;
      }
    }
  }

  _h_nTrans_Kaon->fill(pTlead / GeV, numTrans_Kaon / (8.0 * PI / 3.0));
  _h_nTrans_Lambda->fill(pTlead / GeV, numTrans_Lambda / (8.0 * PI / 3.0));
  _h_ptsumTrans_Kaon->fill(pTlead / GeV, ptSumTrans_Kaon / (GeV * (8.0 * PI / 3.0)));
  _h_ptsumTrans_Lambda->fill(pTlead / GeV, ptSumTrans_Lambda / (GeV * (8.0 * PI / 3.0)));
}

private:

Profile1DPtr _h_nTrans_Kaon;
Profile1DPtr _h_nTrans_Lambda;
Profile1DPtr _h_ptsumTrans_Kaon;
Profile1DPtr _h_ptsumTrans_Lambda;

};

RIVET_DECLARE_PLUGIN(CMS_2012_PAS_QCD_11_010);

} ```