Rivet analyses
J/ψ and ψ(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/ψ and ψ(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 ψ(2S) to the J/ψ.
Source
code:CMS_2012_I944755.cc
// -*- 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);
}