Rivet analyses

title: ALICE_2018_I1642729

$\Xi_c^ 0 $ production at 7 TeV

Experiment: ALICE (LHC)

Inspire ID: 1642729

Status: VALIDATED

Authors: - Peter Richardson

References: - Phys.Lett.B 781 (2018) 8-19, 2018

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - hadronic events

Differential cross section in $p_\perp$ for prompt $\Xi_c^0$ production at 7 TeV

Source code:ALICE_2018_I1642729.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief Xi_c0 at 7 TeV class ALICE_2018_I1642729 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2018_I1642729);


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

/// Book histograms and initialise projections before the run
void init() {
  // projection
  declare(UnstableParticles(Cuts::pid == 4132 || Cuts::pid == 421), "UFS");
  // histos
  book(_h_Xi_pT[0], 1, 1, 1);
  book(_h_Xi_pT[1], "TMP/pT_Xi", refData(2, 1, 1));
  book(_h_D0_pT, "TMP/pT_D0", refData(2, 1, 1));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  // Final state of unstable particles to get particle spectra
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");
  for (const Particle& p : ufs.particles()) {
    // no mixing
    if (p.children().size() == 1 || p.children()[0].abspid() == p.abspid()) continue;
    // rapidity cut
    if (p.absrap() > 0.5) continue;
    const double pT = p.perp();
    if (p.pid() == 421) {
      _h_D0_pT->fill(pT);
    }
    else {
      _h_Xi_pT[0]->fill(pT);
      _h_Xi_pT[1]->fill(pT);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  const double factor = crossSection() / microbarn / sumOfWeights();
  // from PDG value of Xi_x0-> Xi- pi+ and ALICe measurement of ratio to semileptonic
  const double br = 0.0197;
  for (unsigned int ix = 0; ix < 2; ++ix) {
    scale(_h_Xi_pT[ix], br * factor);
  }
  scale(_h_D0_pT, factor);
  Estimate1DPtr tmp;
  book(tmp, 2, 1, 1);
  divide(_h_Xi_pT[1], _h_D0_pT, tmp);
}

/// @}


/// @name Histograms
/// @{
Histo1DPtr _h_Xi_pT[2], _h_D0_pT;
/// @}

};

RIVET_DECLARE_PLUGIN(ALICE_2018_I1642729);

} ```