Rivet analyses

title: MC_MET

Monte Carlo validation observables for missing transverse energy

Experiment: ()

Status: VALIDATED

Authors: - Andy Buckley

References: none listed

Beams: * *

Beam energies: ANY

Run details: - Any event type, with or without "real MET".

Reports vector and scalar transverse momentum sums, based on total or $|\eta| < 5$ detector acceptances.

Source code:MC_MET.cc

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

include "Rivet/Analysis.hh"

include "Rivet/Projections/FinalState.hh"

include "Rivet/Projections/InvisibleFinalState.hh"

include "Rivet/Projections/MissingMomentum.hh"

include "Rivet/Projections/Smearing.hh"

namespace Rivet {

/// @brief MC validation analysis for truth and reco MET and SET observables class MC_MET : public Analysis { public:

RIVET_DEFAULT_ANALYSIS_CTOR(MC_MET);


void init() {

  const FinalState inclfs;
  const FinalState calofs(Cuts::abseta < 5);
  const MissingMomentum inclmm(inclfs);
  const MissingMomentum calomm(calofs);

  declare(inclmm, "InclMET");
  declare(calomm, "CaloMET");
  declare(SmearedMET(calomm, MET_SMEARPARAMS_ATLAS_RUN2), "RecoMET");

  declare(InvisibleFinalState(), "InvisibleFS");
  declare(InvisibleFinalState(OnlyDirect::YES), "DirectInvisibleFS");

  const double METMAX = sqrtS() / 5, SETMAX = sqrtS() / 3;

  book(_h["met_incl"], "met_incl", logspace(50, 10, METMAX / GeV));
  book(_h["met_calo"], "met_calo", logspace(50, 10, METMAX / GeV));
  book(_h["met_reco"], "met_reco", logspace(50, 10, METMAX / GeV));

  book(_h["mpt_incl"], "mpt_incl", logspace(50, 10, METMAX / GeV));
  book(_h["mpt_calo"], "mpt_calo", logspace(50, 10, METMAX / GeV));
  book(_h["mpt_reco"], "mpt_reco", logspace(50, 10, METMAX / GeV));

  book(_h["set_incl"], "set_incl", logspace(50, 10, SETMAX / GeV));
  book(_h["set_calo"], "set_calo", logspace(50, 10, SETMAX / GeV));
  book(_h["set_reco"], "set_reco", logspace(50, 10, SETMAX / GeV));

  book(_h["pT_inv"], "pT_inv", logspace(50, 10, METMAX / GeV));
  book(_h["pT_directinv"], "pT_directinv", logspace(50, 10, METMAX / GeV));

  book(_h["mass_inv"], "mass_inv", logspace(100, 10, METMAX / GeV));
  book(_h["mass_directinv"], "mass_directinv", logspace(100, 10, METMAX / GeV));

  book(_h["rap_inv"], "rap_inv", 50, -5., 5.);
  book(_h["rap_directinv"], "rap_directinv", 50, -5., 5.);
}


void analyze(const Event& event) {

  // Inclusive truth MET, etc.
  const METFinder& mmincl = apply<MissingMomentum>(event, "InclMET");
  _h["met_incl"]->fill(mmincl.met() / GeV);
  _h["mpt_incl"]->fill(mmincl.mpt() / GeV);
  _h["set_incl"]->fill(mmincl.set() / GeV);

  // Calo-acceptance truth MET, etc.
  const METFinder& mmcalo = apply<MissingMomentum>(event, "CaloMET");
  _h["met_calo"]->fill(mmcalo.met() / GeV);
  _h["mpt_calo"]->fill(mmcalo.mpt() / GeV);
  _h["set_calo"]->fill(mmcalo.set() / GeV);

  // (ATLAS) reco MET, etc.
  const METFinder& mmreco = apply<SmearedMET>(event, "RecoMET");
  _h["met_reco"]->fill(mmreco.met() / GeV);
  _h["mpt_reco"]->fill(mmreco.mpt() / GeV);
  _h["set_reco"]->fill(mmreco.set() / GeV);

  // Compute alternative MET from invisible particles, including from hadron decays
  const ParticleFinder& allinvisibles = apply<FinalState>(event, "InvisibleFS");
  if (!allinvisibles.empty()) {
    FourMomentum invsum = sumP4(allinvisibles.particles());
    _h["pT_inv"]->fill(invsum.pT() / GeV);
    _h["mass_inv"]->fill(invsum.mass() / GeV);
    _h["rap_inv"]->fill(invsum.rapidity());
  }

  // Compute alternative MET from direct, invisible particles only
  const ParticleFinder& directinvisibles = apply<FinalState>(event, "DirectInvisibleFS");
  if (!directinvisibles.empty()) {
    FourMomentum invsum = sumP4(directinvisibles.particles());
    _h["pT_directinv"]->fill(invsum.pT() / GeV);
    _h["mass_directinv"]->fill(invsum.mass() / GeV);
    _h["rap_directinv"]->fill(invsum.rapidity());
  }
}


void finalize() {
  const double sf = crossSectionPerEvent() / picobarn;
  scale(_h, sf);
}

private:

map<string, Histo1DPtr> _h;

};

RIVET_DECLARE_PLUGIN(MC_MET);

} ```