Rivet analyses

title: CMS_2012_I944755

J/$\psi$ and $\psi(2S)$ production at 7 TeV

Experiment: CMS (LHC)

Inspire ID: 944755

Status: VALIDATED

Authors: - Peter Richardson

References: - JHEP 02 (2012) 011 - arXiv: 1111.1557 - Expt page: CMS-BPH-10-014

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - J/psi and psi(2s) production in pp

Measurement of prompt and non-prompt $J/\psi$ and $\psi(2S)$ at 7 TeV by the CMS collaboration. The transverse momentum spectra are measured in a number of rapidity intervals, together with the ratio of the production of the $\psi(2S)$ to the $J/\psi$.

Source code:CMS_2012_I944755.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief J/psi and psi(2S) at 7 TeV class CMS_2012_I944755 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2012_I944755);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(), "UFS");
  // J/psi/psi(2s) histos
  for (unsigned int ipsi = 0; ipsi < 2; ++ipsi) {
    for (unsigned int iprompt = 0; iprompt < 2; ++iprompt) {
      book(_h_pT[ipsi][iprompt], "TMP/pT_" + toString(ipsi) + "_" + toString(iprompt),
           refData(20, 1, 1 + iprompt));
    }
    const vector<double> raps = ipsi == 0 ? vector<double>({0., 0.9, 1.2, 1.6, 2.1, 2.4})
                                          : vector<double>({0., 1.2, 1.6, 2.4});
    for (unsigned int iprompt = 0; iprompt < 3; ++iprompt) {
      book(_h_psi[ipsi][iprompt], raps);
      if (ipsi == 1 && iprompt < 2) {
        book(_h_ratio[0][iprompt], raps);
        book(_h_ratio[1][iprompt], raps);
      }
      for (unsigned int iy = 1; iy < raps.size(); ++iy) {
        if (iprompt < 2) {
          book(_h_psi[ipsi][iprompt]->bin(iy), iy + 5 * ipsi, 1, 1 + iprompt);
        }
        else {
          book(_h_psi[ipsi][iprompt]->bin(iy), "TMP/psi_" + toString(ipsi) + "_" + toString(iy),
               refData(iy + 5 * ipsi, 1, 1));
        }
        if (iprompt < 2 && ipsi == 1) {
          book(_h_ratio[0][iprompt]->bin(iy), "TMP/ratio_0_" + toString(iprompt) + "_" + toString(iy),
               refData(16 + iy, 1, 1 + iprompt));
          book(_h_ratio[1][iprompt]->bin(iy), "TMP/ratio_1_" + toString(iprompt) + "_" + toString(iy),
               refData(16 + iy, 1, 1 + iprompt));
        }
      }
    }
  }
}


/// 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");
  // loop over onium states
  for (const Particle& p : ufs.particles(Cuts::pid == 443 || Cuts::pid == 100443)) {
    // cuts on rapidity
    const double y = p.absrap();
    if (y > 2.4) continue;
    const double pT = p.perp();
    // prompt
    unsigned int iprompt = p.fromBottom();
    unsigned int ipsi = p.pid() / 100000;
    _h_psi[ipsi][iprompt]->fill(y, pT);
    _h_psi[ipsi][2]->fill(y, pT);
    _h_ratio[ipsi][iprompt]->fill(y, pT);
    _h_pT[ipsi][iprompt]->fill(pT);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // 0.5 due folded rapidity
  const double factor = 0.5 * crossSection() / nanobarn / sumOfWeights();
  // branching ratios to muons
  const vector<double> brs = {0.05961, 0.00793};
  for (unsigned int ipsi = 0; ipsi < 2; ++ipsi) {
    for (unsigned int iprompt = 0; iprompt < 2; ++iprompt) {
      scale(_h_psi[ipsi][iprompt], factor * brs[ipsi]);
      divByGroupWidth(_h_psi[ipsi][iprompt]);
      scale(_h_ratio[ipsi][iprompt], factor * brs[ipsi]);
      divByGroupWidth(_h_ratio[ipsi][iprompt]);
      scale(_h_pT[ipsi][iprompt], factor * brs[ipsi]);
    }
    scale(_h_psi[ipsi][2], factor * brs[ipsi]);
    divByGroupWidth(_h_psi[ipsi][2]);
  }
  // ratios psi(2S) over J/psi
  for (unsigned int iprompt = 0; iprompt < 2; ++iprompt) {
    for (unsigned int iy = 0; iy < _h_ratio[0][iprompt]->numBins(); ++iy) {
      Estimate1DPtr tmp;
      book(tmp, 17 + iy, 1, 1 + iprompt);
      divide(_h_ratio[1][iprompt]->bin(1 + iy), _h_ratio[0][iprompt]->bin(1 + iy), tmp);
    }
    Estimate1DPtr tmp;
    book(tmp, 20, 1, 1 + iprompt);
    divide(_h_pT[1][iprompt], _h_pT[0][iprompt], tmp);
  }
  // non-prompt fraction
  for (unsigned int ipsi = 0; ipsi < 2; ++ipsi) {
    for (unsigned int iy = 0; iy < _h_psi[ipsi][1]->numBins(); ++iy) {
      Estimate1DPtr tmp;
      book(tmp, 21 + iy + 5 * ipsi, 1, 1);
      efficiency(_h_psi[ipsi][1]->bin(1 + iy), _h_psi[ipsi][2]->bin(1 + iy), tmp);
    }
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DGroupPtr _h_psi[2][3];
Histo1DGroupPtr _h_ratio[2][2];
Histo1DPtr _h_pT[2][2];
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2012_I944755);

} ```