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| // -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/WFinder.hh"
#include "Rivet/Projections/LeadingParticlesFinalState.hh"
#include "Rivet/Projections/IdentifiedFinalState.hh"
namespace Rivet {
/// @brief D0 Run II measurement of W charge asymmetry
///
/// @author Andy Buckley
/// @author Gavin Hesketh
class D0_2008_S7837160 : public Analysis {
public:
RIVET_DEFAULT_ANALYSIS_CTOR(D0_2008_S7837160);
/// @name Analysis methods
/// @{
// Book histograms and set up projections
void init() {
// Projections
FinalState fs;
/// @todo Use separate pT and ETmiss cuts in WFinder
const WFinder wfe(fs, Cuts::abseta < 5 && Cuts::pT > 25*GeV, PID::ELECTRON, 60.0*GeV, 100.0*GeV, 25.0*GeV, 0.2);
declare(wfe, "WFe");
// Histograms (temporary +- charge histos and scatters to store the calculated asymmetries)
for (size_t pmindex = 0; pmindex < 2; ++pmindex) {
const string suffix = (pmindex == 0) ? "plus" : "minus";
book(_hs_dsigpm_deta_25_35[pmindex] ,"TMP/dsigpm_deta_25_35_" + suffix, refData(1, 1, 1));
book(_hs_dsigpm_deta_35[pmindex] ,"TMP/dsigpm_deta_35_" + suffix, refData(1, 1, 2));
book(_hs_dsigpm_deta_25[pmindex] ,"TMP/dsigpm_deta_25_" + suffix, refData(1, 1, 3));
}
book(_h_asym1, 1, 1, 1);
book(_h_asym2, 1, 1, 2);
book(_h_asym3, 1, 1, 3);
}
/// Do the analysis
void analyze(const Event & event) {
const WFinder& wf = apply<WFinder>(event, "WFe");
if (wf.bosons().size() == 0) {
MSG_DEBUG("No W candidates found: vetoing");
vetoEvent;
}
// Get the e+- momentum, and an effective charge including the eta sign
/// @todo Is it correct to multiply the eta sign into the charge to "fold" the plot?
const FourMomentum p_e = wf.constituentLeptons()[0].momentum();
const int chg_e = sign(p_e.eta()) * sign(charge(wf.constituentLeptons()[0]));
assert(chg_e == 1 || chg_e == -1);
MSG_TRACE("Charged lepton sign = " << chg_e);
// Fill histos with appropriate +- indexing
const size_t pmindex = (chg_e > 0) ? 0 : 1;
if (p_e.Et() < 35*GeV) _hs_dsigpm_deta_25_35[pmindex]->fill(fabs(p_e.eta()));
else _hs_dsigpm_deta_35[pmindex]->fill(fabs(p_e.eta()));
_hs_dsigpm_deta_25[pmindex]->fill(fabs(p_e.eta()));
}
/// @brief Finalize
///
/// Construct asymmetry: (dsig+/deta - dsig-/deta) / (dsig+/deta + dsig-/deta) for each ET region
void finalize() {
calc_asymm(_hs_dsigpm_deta_25_35, _h_asym1);
calc_asymm(_hs_dsigpm_deta_35, _h_asym2);
calc_asymm(_hs_dsigpm_deta_25, _h_asym3);
_h_asym1->scaleY(100.);
_h_asym2->scaleY(100.);
_h_asym3->scaleY(100.);
}
/// @}
private:
/// @name Helper functions for constructing asymmetry histograms in finalize()
/// @{
void calc_asymm(const Histo1DPtr plus, const Histo1DPtr minus, Scatter2DPtr target) {
divide(*plus - *minus, *plus + *minus, target);
}
void calc_asymm(const Histo1DPtr histos[2], Scatter2DPtr target) {
calc_asymm(histos[0], histos[1], target);
}
/// @}
/// @name Histograms
/// @{
Histo1DPtr _hs_dsigpm_deta_25_35[2], _hs_dsigpm_deta_35[2], _hs_dsigpm_deta_25[2];
Scatter2DPtr _h_asym1, _h_asym2, _h_asym3;
/// @}
};
RIVET_DECLARE_ALIASED_PLUGIN(D0_2008_S7837160, D0_2008_I791230);
}
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