Rivet analyses

title: ALICE_2014_I1243865

Multi-Strange Baryon production at mid rapidity in Pb--Pb at 2.76 TeV/nn

Experiment: ALICE (LHC)

Inspire ID: 1243865

Status: UNVALIDATED

Authors: - Cody B Duncan - Patrick Kirchgaesser - Johannes Bellm

References: - Phys.Lett. B728 (2014) 216-227 - 10.1016/j.physletb.2013.11.048 - arXiv: 1307.5543

Beams: 1000822080 1000822080

Beam energies: (287040.0, 287040.0)GeV

Run details: - Analysis of multi-strange baryon production at $\sqrt{s} = 2.76~\mathrm{TeV}$ for Pb-Pb collisions.

Measurements of transverse momentum (pT) spectra for charged Xi and Omega hyperon production at mid-rapidity in several centrality intervals for Pb-Pb collisions at sqrt(sNN) = 2.76 TeV recorded in 2010. Mid-rapidity yields, integrated over pT, have also been determined, together with the enhancements with respect to pp collisions and the hyperon-to-pion production ratios

Source code:ALICE_2014_I1243865.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Analyses/AliceCommon.hh"

include "Rivet/Projections/CentralityProjection.hh"

include "Rivet/Projections/HepMCHeavyIon.hh"

include "Rivet/Tools/Cuts.hh"

namespace Rivet {

class ALICE_2014_I1243865 : public Analysis {

// @brief Multi-strange baryon production at mid-rapidity in 2.76 TeV Pb--Pb collisions

public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2014_I1243865);


// Book histograms and projections etc.
void init() {
  // Particles of interest.
  declare(ALICE::PrimaryParticles(Cuts::absrap < 0.5), "CFS");

  // The event trigger.
  declare(ALICE::V0AndTrigger(), "V0-AND");

  // The centrality projection.
  declareCentrality(ALICE::V0MMultiplicity(), "ALICE_2015_CENT_PBPB", "V0M", "V0M");

  // Access the HepMC heavy ion info
  declare(HepMCHeavyIon(), "HepMC");

  // Xi Baryons.
  size_t ixi = 0;
  _histPtXi.resize(5);
  _histPtXi_bar.resize(5);
  for (string str : {"d01-", "d02-", "d03-", "d04-", "d05-"}) {
    book(_histPtXi[ixi], str + "x01-y01");
    book(_histPtXi_bar[ixi], str + "x01-y02");
    ixi += 1;
  }

  // Omega Baryons.
  size_t iom = 0;
  _histPtOmega.resize(5);
  _histPtOmega_bar.resize(5);
  for (string str : {"d06-", "d07-", "d08-", "d09-", "d10-"}) {
    book(_histPtOmega[iom], str + "x01-y01");
    book(_histPtOmega_bar[iom], str + "x01-y02");
    iom += 1;
  }

  // Sum of weights for the centrality intervals.
  sow.resize(_histPtOmega.size());
  for (int i = 0, N = _histPtOmega.size(); i < N; ++i) {
    book(sow[i], "sow_" + toString(i));
  }

  book(_histXitoPi, "d14-x01-y01");
  book(_histOmegatoPi, "d14-x01-y02");
}


void analyze(const Event& event) {
  // Event trigger.
  if (!apply<ALICE::V0AndTrigger>(event, "V0-AND")()) vetoEvent;

  // Centrality.
  const CentralityProjection& cent = apply<CentralityProjection>(event, "V0M");
  const double c = cent();

  int centralityclass = -1;
  if (c > 0. && c <= 10) centralityclass = 0;
  if (c > 10. && c <= 20) centralityclass = 1;
  if (c > 20. && c <= 40) centralityclass = 2;
  if (c > 40. && c <= 60) centralityclass = 3;
  if (c > 60. && c <= 80) centralityclass = 4;
  if (centralityclass == -1) vetoEvent;
  // Fill sum of weights
  sow[centralityclass]->fill();
  int nPions = 0;
  int nXi = 0;
  int nOmega = 0;
  for (const Particle& p : apply<ALICE::PrimaryParticles>(event, "CFS").particles()) {
    const double pT = p.pT() / GeV;
    switch (p.pid()) {
      case 211: nPions++; break;
      case 3312:
        _histPtXi[centralityclass]->fill(pT);
        nXi++;
        break;
      case -3312:
        _histPtXi_bar[centralityclass]->fill(pT);
        nXi++;
        break;
      case 3334:
        _histPtOmega[centralityclass]->fill(pT);
        nOmega++;
        break;
      case -3334:
        _histPtOmega_bar[centralityclass]->fill(pT);
        nOmega++;
        break;
    }
  }
  // Extract Npart form GenEvent. TODO: Unclear how to do
  // this in HepMC3
  const HepMCHeavyIon& hi = apply<HepMCHeavyIon>(event, "HepMC");
  if (nPions != 0) {
    const double npart = hi.Npart_proj() + hi.Npart_targ();
    if (nXi != 0) _histXitoPi->fill(npart, double(nXi) / double(nPions));
    if (nOmega != 0) _histOmegatoPi->fill(npart, double(nOmega) / double(nPions));
  }
}

void finalize() {
  for (int i = 0, N = _histPtOmega.size(); i < N; ++i) {
    const double s = 1. / sow[i]->sumW();
    _histPtXi[i]->scaleW(s);
    _histPtXi_bar[i]->scaleW(s);
    _histPtOmega[i]->scaleW(s);
    _histPtOmega_bar[i]->scaleW(s);
  }
}

private:

vector<Histo1DPtr> _histPtXi;
vector<Histo1DPtr> _histPtXi_bar;
vector<Histo1DPtr> _histPtOmega;
vector<Histo1DPtr> _histPtOmega_bar;
vector<CounterPtr> sow;
Profile1DPtr _histXitoPi;
Profile1DPtr _histOmegatoPi;

};

RIVET_DECLARE_PLUGIN(ALICE_2014_I1243865);

} ```