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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/Thrust.hh"
namespace Rivet {
/// @brief Add a short analysis description here
class OPAL_2003_I595335 : public Analysis {
public:
/// Constructor
RIVET_DEFAULT_ANALYSIS_CTOR(OPAL_2003_I595335);
/// @name Analysis methods
//@{
/// Book histograms and initialise projections before the run
void init() {
// Initialise and register projections
declare(Beam(), "Beams");
const ChargedFinalState cfs = ChargedFinalState();
declare(cfs, "CFS");
declare(Thrust(cfs), "Thrust");
book(_h_pT_in , 1, 1, 1);
book(_h_pT_out, 2, 1, 1);
book(_h_y , 3, 1, 1);
book(_h_x , 4, 1, 1);
book(_h_xi , 5, 1, 1);
book(_wSum,"TMP/wSum");
}
/// Perform the per-event analysis
void analyze(const Event& event) {
// First, veto on leptonic events by requiring at least 4 charged FS particles
const ChargedFinalState& cfs = apply<ChargedFinalState>(event, "CFS");
const size_t numParticles = cfs.particles().size();
// Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
if (numParticles < 2) {
MSG_DEBUG("Failed leptonic event cut");
vetoEvent;
}
MSG_DEBUG("Passed leptonic event cut");
_wSum->fill();
// 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);
// Thrusts
MSG_DEBUG("Calculating thrust");
const Thrust& thrust = apply<Thrust>(event, "Thrust");
for (const Particle& p : cfs.particles()) {
const Vector3 mom3 = p.p3();
const double energy = p.E();
const double pTinT = dot(mom3, thrust.thrustMajorAxis());
const double pToutT = dot(mom3, thrust.thrustMinorAxis());
_h_pT_in ->fill(fabs(pTinT/GeV) );
_h_pT_out->fill(fabs(pToutT/GeV));
const double momT = dot(thrust.thrustAxis(), mom3);
const double rapidityT = 0.5 * std::log((energy + momT) / (energy - momT));
_h_y->fill(fabs(rapidityT));
const double mom = mom3.mod();
const double scaledMom = mom/meanBeamMom;
const double logInvScaledMom = -std::log(scaledMom);
_h_xi->fill(logInvScaledMom);
_h_x ->fill(scaledMom );
}
}
/// Normalise histograms etc., after the run
void finalize() {
scale(_h_pT_in , 1./ *_wSum);
scale(_h_pT_out, 1./ *_wSum);
scale(_h_y , 1./ *_wSum);
scale(_h_x , 1./ *_wSum);
scale(_h_xi , 1./ *_wSum);
}
//@}
/// @name Histograms
//@{
Histo1DPtr _h_pT_in,_h_pT_out,_h_y,_h_x,_h_xi;
CounterPtr _wSum;
//@}
};
// The hook for the plugin system
RIVET_DECLARE_PLUGIN(OPAL_2003_I595335);
}
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