Rivet analyses

title: LHCB_2015_I1316329

Prompt and non-prompt $\eta_c$ production at 7 and 8 TeV

Experiment: LHCB (LHC)

Inspire ID: 1316329

Status: VALIDATED

Authors: - Peter Richardson

References: - Eur.Phys.J.C 75 (2015) 7, 311

Beams: p+ p+

Beam energies: (3500.0, 3500.0); (4000.0, 4000.0)GeV

Run details: - hadronic events with eta_c production

Measurement of the differential cross section with respect to $p_\perp$ of $\eta_c$ production at 7 and 8 TeV by the LHCb collaboration.

Source code:LHCB_2015_I1316329.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/UnstableParticles.hh"

namespace Rivet {

/// @brief eta_c production at 7,8 TeV class LHCB_2015_I1316329 : public Analysis { public:

/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(LHCB_2015_I1316329);


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

/// Book histograms and initialise projections before the run
void init() {
  declare(UnstableParticles(), "UFS");

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

    int ih = int(en == 8000) + 1;
    for (size_t ix = 0; ix < 2; ++ix) {
      book(_h_etac[en + ix], ih + 2 * ix, 1, 1);
    }
  }
  raiseBeamErrorIf(_sqs == 0);
}


/// 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(Cuts::pid == 441)) {
    // prompt/non-prompt
    bool nonPrompt = p.fromBottom();
    double absrap = p.absrap();
    double xp = p.perp();
    if (absrap > 2. && absrap < 4.5) {
      _h_etac[_sqs + nonPrompt]->fill(xp);
    }
  }
}


/// Normalise histograms etc., after the run
void finalize() {
  // 1/2 due rapidity folding +/-
  scale(_h_etac, 0.5 * crossSection() / nanobarn / sumOfWeights());
}

/// @}


/// @name Histograms
/// @{
map<int, Histo1DPtr> _h_etac;
int _sqs = 0;
/// @}

};

RIVET_DECLARE_PLUGIN(LHCB_2015_I1316329);

} ```