Rivet analyses

title: ALICE_2017_I1511865

Forward J$/\psi$ and $\psi(2S)$ production at $13$ and $5.02$ TeV

Experiment: ALICE (LHC)

Inspire ID: 1511865

Status: VALIDATED

Authors: - Peter Richardson

References: - Eur.Phys.J.C 77 (2017) 392, 2017

Beams: p+ p+

Beam energies: (2510.0, 2510.0); (6500.0, 6500.0)GeV

Run details: - J/Psi and psi(21S) production

Measurement of forward J$/\psi$ and $\psi(2S)$ production at $13$ and $5.02$ TeV by the ALICE collaboration.

Source code:ALICE_2017_I1511865.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief J/psi, and psi(2s) production at 5.02 and 13 TeV class ALICE_2017_I1511865 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ALICE_2017_I1511865);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(Cuts::pid == 443 || Cuts::pid == 100443), "UFS");

  for (double eVal : allowedEnergies()) {
    const string en = toString(round(eVal));
    if (isCompatibleWithSqrtS(eVal)) _sqs = en;

    size_t offset = (en == "5020"s) ? 6 : 0;
    book(_h[en + "JPsi_pT"], 1 + offset, 1, 1);
    book(_h[en + "JPsi_y"], 2 + offset, 1, 1);
  }
  raiseBeamErrorIf(_sqs.empty());

  book(_h["Psi2S_pT"], 3, 1, 1);
  book(_h["Psi2S_y"], 4, 1, 1);
  book(_h["JPsi_pT2"], "TMP/JPsi_pY", refData(5, 1, 1));
  book(_h["JPsi_y2"], "TMP/JPsi_y", refData(6, 1, 1));
}


/// Perform the per-event analysis
void analyze(const Event& event) {
  // loop over J/Psi
  for (const Particle& p : apply<UnstableParticles>(event, "UFS").particles()) {
    // rapidity cut
    const double absrap = p.absrap();
    if (absrap < 2.5 || absrap > 4) continue;
    const double xp = p.perp();
    // J/Psi
    if (p.pid() == 443) {
      if (_sqs != "5020"s) {
        if (xp > 30.) continue;
        _h[_sqs + "JPsi_pT"]->fill(xp);
        _h[_sqs + "JPsi_y"]->fill(absrap);
        if (xp <= 16.) {
          _h["JPsi_pT2"]->fill(xp);
          _h["JPsi_y2"]->fill(absrap);
        }
      }
      else {
        if (xp > 12.) continue;
        _h[_sqs + "JPsi_pT"]->fill(xp);
        _h[_sqs + "JPsi_y"]->fill(absrap);
      }
    }
    // psi(2S)
    else if (_sqs != "5020"s) {
      if (xp > 16.) continue;
      _h["Psi2S_pT"]->fill(xp);
      _h["Psi2S_y"]->fill(absrap);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // factor 1/2 due folding +/- rap
  const double fact = 0.5 * crossSection() / nanobarn / sumOfWeights();
  // factor 1.5 for rapidity range 2.5-4
  for (auto& item : _h) {
    if (item.first.find("_pT") != string::npos) {
      scale(item.second, fact / 1.5);
    }
    else {
      scale(item.second, fact);
    }
  }

  Estimate1DPtr tmp;
  book(tmp, 5, 1, 1);
  divide(_h["Psi2S_pT"], _h["JPsi_pT2"], tmp);
  book(tmp, 6, 1, 1);
  divide(_h["Psi2S_y"], _h["JPsi_y2"], tmp);
}

///@}


/// @name Histograms
///@{
map<string, Histo1DPtr> _h;
Histo1DPtr _h_JPsi_pT[2], _h_JPsi_y[2];
Histo1DPtr _h_Psi2S_pT, _h_Psi2S_y;
Histo1DPtr _h_JPsi_pT2, _h_JPsi_y2;

string _sqs = "";
///@}

};

RIVET_DECLARE_PLUGIN(ALICE_2017_I1511865);

} ```