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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/Beam.hh"
namespace Rivet {
/// @brief ALEPH pi+-, K+-, p and pbar differential cross-sections at the Z peak
class ALEPH_1995_I382179 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(ALEPH_1995_I382179);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(Beam(), "Beams");
declare(ChargedFinalState(), "FS");
// Book histograms
book(_histXpPion , 1, 1, 1);
book(_histXpKaon , 2, 1, 1);
book(_histXpProton , 3, 1, 1);
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
const FinalState& fs = apply<FinalState>(event, "FS");
if (fs.particles().size() < 2) {
MSG_DEBUG("Failed ncharged cut");
vetoEvent;
}
MSG_DEBUG("Passed ncharged cut");
// Get beams and average beam momentum
const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
const double meanBeamMom = ( beams.first.p3().mod() + beams.second.p3().mod() ) / 2.0;
MSG_DEBUG("Avg beam momentum = " << meanBeamMom);
for (const Particle& p : fs.particles()) {
int id = p.abspid();
// charged pions
if (id == PID::PIPLUS || id == PID::PIMINUS) {
_histXpPion->fill(p.p3().mod()/meanBeamMom);
} else if(id == PID::KPLUS || id == PID::KMINUS) {
_histXpKaon->fill(p.p3().mod()/meanBeamMom);
} else if(id == PID::PROTON || id == PID::ANTIPROTON) {
_histXpProton->fill(p.p3().mod()/meanBeamMom);
}
}
}
/// Normalise histograms etc., after the run
void finalize() {
scale(_histXpPion, 1./sumOfWeights());
scale(_histXpKaon, 1./sumOfWeights());
scale(_histXpProton, 1./sumOfWeights());
}
//@}
private:
/// @name Histograms
Histo1DPtr _histXpPion;
Histo1DPtr _histXpKaon;
Histo1DPtr _histXpProton;
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(ALEPH_1995_I382179);
}
|