Rivet analyses

title: CMS_2011_I878118

J/$\psi$ production at 7 TeV

Experiment: CMS (LHC)

Inspire ID: 878118

Status: VALIDATED

Authors: - Peter Richardson

References: - Eur.Phys.J.C 71 (2011) 1575 - arXiv: 1011.4193 - Expt page: CMS-BPH-10-002

Beams: p+ p+

Beam energies: (3500.0, 3500.0)GeV

Run details: - J/psi production in pp

Measurement of prompt and non-prompt $J/\psi$at 7 TeV by the CMS collaboration. The transverse momentum spectra are measured in a number of rapidity intervals.

Source code:CMS_2011_I878118.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief J/psi at 7 TeV class CMS_2011_I878118 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(CMS_2011_I878118);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(), "UFS");
  for (unsigned int ix = 0; ix < 3; ++ix) {
    book(_h_psi[ix], {0., 1.2, 1.6, 2.4});
    for (unsigned int iy = 1; iy < 4; ++iy) {
      if (ix < 2) {
        book(_h_psi[ix]->bin(iy), 1 + iy + ix * 9, 1, 1);
      }
      else {
        book(_h_psi[ix]->bin(iy), "TMP/total" + toString(iy), refData(4 + iy, 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");
  // loop over onium states
  for (const Particle& p : ufs.particles(Cuts::pid == 443)) {
    // cuts on rapidity
    const double y = p.absrap();
    if (y > 2.4) continue;
    const double pT = p.perp();
    // prompt
    unsigned int iprompt = p.fromBottom();
    _h_psi[iprompt]->fill(y, pT);
    _h_psi[2]->fill(y, pT);
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // branching ratio
  const double br = 0.05961;
  // 0.5 due folded rapidity
  scale(_h_psi, 0.5 * br * crossSection() / nanobarn / sumOfWeights());
  divByGroupWidth(_h_psi);
  // non-prompt fraction
  for (unsigned int iy = 0; iy < _h_psi[1]->numBins(); ++iy) {
    Estimate1DPtr tmp;
    book(tmp, 5 + iy, 1, 1);
    efficiency(_h_psi[1]->bin(iy + 1), _h_psi[2]->bin(iy + 1), tmp);
  }
}

/// @}


/// @name Histograms
/// @{
Histo1DGroupPtr _h_psi[3];
/// @}

};

RIVET_DECLARE_PLUGIN(CMS_2011_I878118);

} ```