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Rivet analyses reference

ATLAS_2021_I1852328

WW + $\geq$1 jet production at 13 TeV
Experiment: ATLAS (LHC)
Inspire ID: 1852328
Status: VALIDATED
Authors:
  • Hannes Mildner
References: Beams: p+ p+
Beam energies: (6500.0, 6500.0) GeV
Run details:
  • pp -> WW + jet production at 13 TeV

Fiducial and differential measurements of $W^+W^-$ production in events with at least one hadronic jet are presented. These measurements are sensitive to the properties of gauge boson self interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton--proton collision data collected at $\sqrt{s}=13$ TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139 fb$^{-1}$. Events with exactly one oppositely charged electron-muon pair and at least one hadronic jet with a transverse momentum of $p_{\mathrm{T}}>30$ GeV and a pseudorapidity of $|\eta|<4.5$ are selected. After subtracting the background contributions and correcting for detector effects, the jet-inclusive $W^+W^-+\ge 1$ fiducial cross-section and $W^+W^-$+jets differential cross-sections with respect to several kinematic variables are measured, for the first time at the LHC. These measurements include leptonic quantities, like the lepton transverse momenta as well as the transverse mass of the $W^+W^-$ system, and also jet related observables like the leading jet transverse momentum and the jet multiplicity.

Source code: ATLAS_2021_I1852328.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/MissingMomentum.hh"
#include "Rivet/Projections/PromptFinalState.hh"
#include "Rivet/Projections/DressedLeptons.hh"
#include "Rivet/Projections/VetoedFinalState.hh"


namespace Rivet {


  /// @brief WW production at 13 TeV
  class ATLAS_2021_I1852328 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(ATLAS_2021_I1852328);


    /// Book histograms and initialise projections before the run
    void init() {
     
      const FinalState fs(Cuts::abseta < 5.);

      // Project photons for dressing
      FinalState photons(Cuts::abspid == PID::PHOTON);

      // Cuts for leptons
      Cut lepton_cuts = (Cuts::abseta < 2.5) && (Cuts::pT > 27*GeV);
          
      // Project dressed leptons (e/mu not from tau) with pT > 27 GeV and |eta| < 2.5
      PromptFinalState lep_bare(Cuts::abspid == PID::MUON || Cuts::abspid == PID::ELECTRON);
      lep_bare.acceptTauDecays(false);
      DressedLeptons lep_dressed(photons, lep_bare, 0.1, lepton_cuts, false);
      declare(lep_dressed,"lep_dressed");

      // Leptons (+ dressed photons) to be removed from jets
      PromptFinalState bare_mu(Cuts::abspid == PID::MUON, true); // true = use muons from prompt tau decays
      DressedLeptons all_dressed_mu(photons, bare_mu, 0.1, Cuts::abseta < 2.5, true);
      PromptFinalState bare_el(Cuts::abspid == PID::ELECTRON, true); // true = use electrons from prompt tau decays
      DressedLeptons all_dressed_el(photons, bare_el, 0.1, Cuts::abseta < 2.5, true);

      // Define hadrons as everything but dressed leptons (for jet clustering)
      VetoedFinalState hadrons(fs);
      hadrons.addVetoOnThisFinalState(all_dressed_el);
      hadrons.addVetoOnThisFinalState(all_dressed_mu);
      declare(hadrons, "hadrons");

      // Get MET from generic invisibles
      MissingMomentum mm(fs);
      declare(mm, "met");
      
      // Project jets
      FastJets jets(hadrons, FastJets::ANTIKT, 0.4, FastJets::Muons::ALL, FastJets::Invisibles::DECAY);
      declare(jets, "jets");
    
      book(_h["xs_inf"], 1, 1, 1);
      book(_h["xs_bveto_inf"], 1, 1, 2);
      book(_h["lep0pt"], 2, 1, 1);
      book(_h["lep0pt_bveto"], 2, 1, 2);
      book(_h["lep1pt"], 5, 1, 1);
      book(_h["lep1pt_bveto"], 5, 1, 2);
      book(_h["jet0pt"], 8, 1, 1);
      book(_h["jet0pt_bveto"], 8, 1, 2);
      book(_h["htjet"], 11, 1, 1);
      book(_h["htjet_bveto"], 11, 1, 2);
      book(_h["st"], 14, 1, 1);
      book(_h["st_bveto"], 14, 1, 2);
      book(_h["mt"], 17, 1, 1);
      book(_h["mt_bveto"], 17, 1, 2);
      book(_h["mll_inf"], 20, 1, 1);
      book(_h["mll_bveto_inf"], 20, 1, 2);
      book(_h["ptll"], 23, 1, 1);
      book(_h["ptll_bveto"], 23, 1, 2);
      book(_h["dphill_inf"], 26, 1, 1);
      book(_h["dphill_bveto_inf"], 26, 1, 2);
      book(_h["yll_inf"], 29, 1, 1);
      book(_h["yll_bveto_inf"], 29, 1, 2);
      book(_h["costhetastar_inf"], 32, 1, 1);
      book(_h["costhetastar_bveto_inf"], 32, 1, 2);
      book(_h["njet"], 35, 1, 1);
      book(_h["njet_bveto"], 35, 1, 2);

      book(_h["mll_jet0pt200_inf"], 38, 1, 1);
      book(_h["mll_jet0pt200_bveto_inf"], 38, 1, 2);
      book(_h["dphill_jet0pt200_inf"], 41, 1, 1);
      book(_h["dphill_jet0pt200_bveto_inf"], 41, 1, 2);

      book(_h["dphil1j0_lep0pt200_inf"], 44, 1, 1);
      book(_h["dphil1j0_lep0pt200_bveto_inf"], 44, 1, 2);
      book(_h["drl1j0_lep0pt200_inf"], 47, 1, 1);
      book(_h["drl1j0_lep0pt200_bveto_inf"], 47, 1, 2);
      book(_h["rl1l0_lep0pt200_inf"], 50, 1, 1);
      book(_h["rl1l0_lep0pt200_bveto_inf"], 50, 1, 2);
      book(_h["rl1j0_lep0pt200"], 53, 1, 1);
      book(_h["rl1j0_lep0pt200_bveto"], 53, 1, 2);

    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {

      // Get invisible
      const MissingMomentum& met = apply<MissingMomentum>(event, "met");

      // Find leptons and sort by pT
      const Particles& leptons = apply<ParticleFinder>(event, "lep_dressed").particlesByPt();

      const Jets& jets = apply<FastJets>(event, "jets").jetsByPt(Cuts::absrap < 4.5 && Cuts::pT > 30*GeV);
      const Jets& btagging_jets = apply<FastJets>(event, "jets").jetsByPt(Cuts::absrap < 2.5 && Cuts::pT > 20*GeV);
      
      // Define observables
 
      const FourMomentum dilep = leptons.size()>1 ? leptons[0].momentum() + leptons[1].momentum() : FourMomentum(0,0,0,0);
      const double lep0pt = leptons.size()>0 ? leptons[0].pT()/GeV : -1;
      const double lep1pt = leptons.size()>1 ? leptons[1].pT()/GeV : -1;
      const double mll = leptons.size()>1 ? dilep.mass()/GeV : -1;
      const double ptll = leptons.size()>1 ? dilep.pT()/GeV : -1;
      const double yll = leptons.size()>1 ? dilep.absrap(): -1; 
      const double dphill = leptons.size()>1 ? fabs(deltaPhi(leptons[0], leptons[1])) : -1.;
      const double costhetastar = leptons.size()>1 ? fabs(tanh((leptons[0].eta() - leptons[1].eta()) / 2)) : -1;
      const double jet0pt = jets.size()>0 ? jets[0].pT()/GeV : -1;
      const double dphil1j0 = leptons.size()>1 and jets.size()>0 ? fabs(deltaPhi(leptons[1], jets[0])) : -1.;
      const double drl1j0 = leptons.size()>1 and jets.size()>0 ? fabs(deltaR(leptons[1], jets[0])) : -1.;
      const double rl1l0 = leptons.size()>1 ? leptons[1].pT()/leptons[0].pT() : -1;
      const double rl1j0 = leptons.size()>1 and jets.size()>0 ? leptons[1].pT()/jets[0].pT() : -1;
      Vector3 dilep_tvec(dilep.px(), dilep.py(),0);
      Vector3 met_tvec = met.vectorMissingPt();
      double et_ll = std::sqrt(dilep_tvec.mod2() + dilep.mass()*dilep.mass());
      const double mt =sqrt(std::pow(et_ll + met.met() ,2) - (dilep_tvec + met_tvec).mod2());
      const int njet = jets.size();
   
      size_t nbtags = count(btagging_jets, hasBTag());
      const double htjet = sum(jets, pT, 0.0);
      const double st = sum(leptons, pT, htjet);

      if (leptons.size()!=2 ) vetoEvent;
      if (leptons[0].abspid() == leptons[1].abspid()) vetoEvent;
      if (leptons[0].pid()*leptons[1].pid()>0) vetoEvent;
      if (dilep.mass() <= 85*GeV)  vetoEvent; 
      if (jets.empty()) vetoEvent;

      _h["xs_inf"]->fill(0.5);
      _h["lep0pt"]->fill(lep0pt);
      _h["lep1pt"]->fill(lep1pt);
      _h["mll_inf"]->fill(mll);
      _h["ptll"]->fill(ptll);
      _h["yll_inf"]->fill(yll);
      _h["dphill_inf"]->fill(dphill);
      _h["costhetastar_inf"]->fill(costhetastar);
      _h["jet0pt"]->fill(jet0pt);
      _h["mt"]->fill(mt);
      _h["njet"]->fill(njet);
      _h["htjet"]->fill(htjet/GeV);
      _h["st"]->fill(st/GeV);
      
      if (lep0pt>200){
	      _h["dphil1j0_lep0pt200_inf"]->fill(dphil1j0);
	      _h["drl1j0_lep0pt200_inf"]->fill(drl1j0);
	      _h["rl1l0_lep0pt200_inf"]->fill(rl1l0);
	      _h["rl1j0_lep0pt200"]->fill(rl1j0);
      }
      if(jet0pt>200){
	     _h["mll_jet0pt200_inf"]->fill(mll);
	     _h["dphill_jet0pt200_inf"]->fill(dphill);
      }
      

      if(nbtags == 0) {
        _h["xs_bveto_inf"]->fill(0.5);
        _h["lep0pt_bveto"]->fill(lep0pt);
        _h["lep1pt_bveto"]->fill(lep1pt);
        _h["mll_bveto_inf"]->fill(mll);
        _h["ptll_bveto"]->fill(ptll);
        _h["yll_bveto_inf"]->fill(yll);
        _h["dphill_bveto_inf"]->fill(dphill);
        _h["costhetastar_bveto_inf"]->fill(costhetastar);
        _h["jet0pt_bveto"]->fill(jet0pt);
        _h["mt_bveto"]->fill(mt);
        _h["njet_bveto"]->fill(njet);
        _h["htjet_bveto"]->fill(htjet);
        _h["st_bveto"]->fill(st);
      
         if (lep0pt>200){
        	  _h["dphil1j0_lep0pt200_bveto_inf"]->fill(dphil1j0);
 	          _h["drl1j0_lep0pt200_bveto_inf"]->fill(drl1j0);
	          _h["rl1l0_lep0pt200_bveto_inf"]->fill(rl1l0);
    	      _h["rl1j0_lep0pt200_bveto"]->fill(rl1j0);
           }
          
         if(jet0pt>200){
	          _h["mll_jet0pt200_bveto_inf"]->fill(mll);
	          _h["dphill_jet0pt200_bveto_inf"]->fill(dphill);
          }
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
    
       const double sf = crossSectionPerEvent()/femtobarn;
      
       scale(_h, sf);
       for (auto& hist : _h) {
          if (hist.first.find("_inf") != string::npos) {
            hist.second->fillBin(hist.second->numBins()-1, hist.second->overflow().sumW());
            hist.second->overflow().reset();
          }
       }
    }

     //@}

  private:

    /// @name Histograms
    map<string, Histo1DPtr> _h;
  };

  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(ATLAS_2021_I1852328);
}