Rivet analyses

title: ATLAS_2018_I1622737

Differential cross sections for $J/\psi$, $\psi(21S)$ and $\Upsilon(1,2,3S)$ at 5.02 TeV

Experiment: ATLAS (LHC)

Inspire ID: 1622737

Status: VALIDATED

Authors: - Peter Richardson

References: - Eur.Phys.J.C 78 (2018) 171, 2018. - Expt page: ATLAS-HION-2014-05 - arXiv: 1709.03089

Beams: p+ p+

Beam energies: (2510.0, 2510.0)GeV

Run details: - hadronic events with onium production

Measurement of the double differential (in $p_\perp$ and $y$) cross section for $J/\psi$, $\psi(2S)$ and $\Upsilon(1,2,3S)$ production at 5.02 TeV by the ATLAS collaboration. Only the proton-proton results are implemented.

Source code:ATLAS_2018_I1622737.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

include "Rivet/Tools/HistoGroup.hh"

namespace Rivet {

/// @brief onium production at 5.02 TeV class ATLAS_2018_I1622737 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ATLAS_2018_I1622737);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(Cuts::pid == 443 || Cuts::pid == 100443 || Cuts::pid == 553
                            || Cuts::pid == 100553 || Cuts::pid == 200553),
          "UFS");

  // binning in y
  const vector<double> ybins = {0., 0.75, 1.5, 2.0};
  // book histos
  for (unsigned int ix = 0; ix < 7; ++ix) {
    book(_h_Onium[ix], ybins);
    for (auto& b : _h_Onium[ix]->bins()) {
      book(b, ix + 1, 1, b.index());
    }
    if (ix == 0 || ix == 2) {
      _axes[ix] = YODA::Axis<double>({8., 9., 10., 11., 12., 13., 14., 16., 18., 22., 30., 40.});
    }
    else if (ix == 1 || ix == 3) {
      _axes[ix] = YODA::Axis<double>({8., 10., 12., 16., 22., 40.});
    }
    else if (ix == 4) {
      _axes[ix] = YODA::Axis<double>({0., 2., 4., 6., 8., 10., 14., 20., 40.});
    }
    else {
      _axes[ix] = YODA::Axis<double>({0., 6., 10., 15., 40.});
    }
  }
}


/// Perform the per-event analysis
void analyze(const Event& event) {

  if (_edges[0].empty()) {
    for (unsigned int ix = 0; ix < 7; ++ix) {
      _edges[ix] = _h_Onium[ix]->bin(1)->xEdges();
    }
  }

  // Final state of unstable particles to get particle spectra
  const UnstableParticles& ufs = apply<UnstableParticles>(event, "UFS");

  for (const Particle& p : ufs.particles()) {
    const double absrap = p.absrap();
    const double xp = p.perp();
    if (p.pid() == 443 || p.pid() == 100443) {
      // prompt/non-prompt
      const bool prompt = !p.fromBottom();
      if (p.pid() == 443) {
        _h_Onium[2 * prompt]->fill(absrap, disc(xp, 2 * prompt));
      }
      else {
        _h_Onium[1 + 2 * prompt]->fill(absrap, disc(xp, 1 + 2 * prompt));
      }
    }
    else if (p.pid() == 553)
      _h_Onium[4]->fill(absrap, disc(xp, 4));
    else if (p.pid() == 100553)
      _h_Onium[5]->fill(absrap, disc(xp, 5));
    else if (p.pid() == 200553)
      _h_Onium[6]->fill(absrap, disc(xp, 6));
  }
}

string disc(const double value, size_t ix) const {
  size_t idx = _axes[ix].index(value);
  if (0 < idx && idx <= _axes[ix].numBins()) return _edges[ix][idx - 1];
  return "OTHER"s;
}


/// Normalise histograms etc., after the run
void finalize() {
  // 0.5 due rapidity folding +/-
  const double factor = 0.5 * crossSection() / nanobarn / sumOfWeights();
  // br to muons PDG 2021 (psi2s is e+e- due large errors on mu+mu-)
  const vector<double> br = {0.05961, 0.00793, 0.05961, 0.00793, 0.0248, 0.0193, 0.0218};
  for (unsigned int ix = 0; ix < 7; ++ix) {
    scale(_h_Onium[ix], factor * br[ix]);
    divByGroupWidth(_h_Onium[ix]);
  }
}

/// @}


/// @name Histograms
/// @{
HistoGroupPtr<double, string> _h_Onium[7];
YODA::Axis<double> _axes[7];
vector<string> _edges[7];
/// @}

};

RIVET_DECLARE_PLUGIN(ATLAS_2018_I1622737);

} ```