HiggsTemplateCrossSections.h

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef TRUTHRIVETTOOLS_HIGGSTEMPLATECROSSSECTIONS_H
#define TRUTHRIVETTOOLS_HIGGSTEMPLATECROSSSECTIONS_H
 
// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Particle.hh"
#include "Rivet/Projections/FastJets.hh"
 
// Definition of the StatusCode and Category enums
// Note: the Template XSec Defs *depends* on having included
//  the TLorentzVector header *before* it is included -- it
//  uses the include guard from TLorentzVector to decide
//  what is available
#include "TLorentzVector.h"
#include "TruthRivetTools/HiggsTemplateCrossSectionsDefs.h"
#include "AtlasHepMC/Relatives.h"
#include "AtlasHepMC/GenEvent.h"
#include "AtlasHepMC/GenVertex.h"
#include "AtlasHepMC/GenParticle.h"
#include "AtlasHepMC/GenRanges.h"
#include "CxxUtils/checker_macros.h"
#include <string>
#include <string_view>
 
 
namespace Rivet {

  class HiggsTemplateCrossSections : public Analysis {
  public:
    // Constructor
    HiggsTemplateCrossSections()
      : Analysis("HiggsTemplateCrossSections"),
        m_HiggsProdMode(HTXS::UNKNOWN) {}
 
  public:


    Particle getLastInstance(const Particle & ptcl) const {
      if ( ptcl.genParticle()->end_vertex() ) {
        if ( !hasChild(ptcl.genParticle(),ptcl.pid()) ) return ptcl;
        else return getLastInstance(ptcl.children()[0]);
      }
      return ptcl;
    }

    bool originateFrom(const Particle& p, const Particles& ptcls ) const {
      auto prodVtx = p.genParticle()->production_vertex();
      if (prodVtx == nullptr) return false;
      // for each ancestor, check if it matches any of the input particles
      for (auto ancestor:Rivet::HepMCUtils::particles(std::move(prodVtx),Relatives::ANCESTORS)){
        for ( const auto & part:ptcls )
          if ( ancestor==part.genParticle() ) return true;
      }
      // if we get here, no ancestor matched any input particle
      return false;
    }

    bool originateFrom(const Particle& p, const Particle& p2 ) const {
      Particles ptcls = {p2}; return originateFrom(p,ptcls);
    }

    bool hasChild(HepMC::ConstGenParticlePtr ptcl, int pdgID) const {
      for (const Particle& child:Particle(*ptcl).children())
        if (child.pid()==pdgID) return true;
      return false;
    }

    bool hasParent(HepMC::ConstGenParticlePtr ptcl, int pdgID) const {
      for (auto parent:Rivet::HepMCUtils::particles(ptcl->production_vertex(),Relatives::PARENTS))
        if (parent->pdg_id()==pdgID) return true;
      return false;
    }

    bool quarkDecay(const Particle &p) const {
      for (const Particle& child:p.children())
        if (PID::isQuark(child.pid())) return true;
      return false;
    }

    bool ChLeptonDecay(const Particle &p) const {
      for (const Particle& child:p.children())
        if (
#if RIVET_VERSION_CODE >= 40000
          PID::isChargedLepton(child.pid())
#else
          PID::isChLepton(child.pid())
#endif // RIVET_VERSION_CODE
          ) return true;
      return false;
    }

    HiggsClassification error(HiggsClassification &cat, HTXS::ErrorCode err,
                              std::string_view msg={}, int NmaxWarnings=20) const {
      // Set the error, and keep statistics
      cat.errorCode = err;
      const auto errIndex = static_cast<std::size_t>(err);
      if (errIndex < std::size(m_errorCount)) {
        ++m_errorCount[errIndex];
      } else {
        MSG_WARNING("Invalid HTXS error code: " << errIndex);
      }
      // Print warning message to the screen/log
      static std::atomic<int> Nwarnings = 0;
      if ( !msg.empty() && ++Nwarnings < NmaxWarnings )
          MSG_WARNING(msg);
 
      return cat;
    }


    HiggsClassification classifyEvent(const Event& event, const HTXS::HiggsProdMode prodMode ) const {
 
      // the classification object
      HiggsClassification cat;
      cat.prodMode = prodMode;
      cat.errorCode = HTXS::UNDEFINED;
      cat.stage0_cat = HTXS::Stage0::UNKNOWN;
      cat.stage1_cat_pTjet25GeV = HTXS::Stage1::UNKNOWN;
      cat.stage1_cat_pTjet30GeV = HTXS::Stage1::UNKNOWN;
      cat.stage1_2_cat_pTjet25GeV = HTXS::Stage1_2::UNKNOWN;
      cat.stage1_2_cat_pTjet30GeV = HTXS::Stage1_2::UNKNOWN;
      cat.stage1_2_fine_cat_pTjet25GeV = HTXS::Stage1_2_Fine::UNKNOWN;
      cat.stage1_2_fine_cat_pTjet30GeV = HTXS::Stage1_2_Fine::UNKNOWN;
 
      if (prodMode == HTXS::UNKNOWN)
        return error(cat,HTXS::PRODMODE_DEFINED,
                     "Unkown Higgs production mechanism. Cannot classify event."
                     " Classification for all events will most likely fail.");
 
      /*****
       * Step 1.
       *  Idenfify the Higgs boson and the hard scatter vertex
       *  There should be only one of each.
       */
 
      auto HSvtx = HepMC::signal_process_vertex(event.genEvent());
      int Nhiggs=0;
      for (auto ptcl : Rivet::HepMCUtils::particles(event.genEvent()) ) {
 
        // a) Reject all non-Higgs particles
        if ( !PID::isHiggs(ptcl->pdg_id()) ) continue;
        // b) select only the final Higgs boson copy, prior to decay
        if ( ptcl->end_vertex() && !hasChild(ptcl,PID::HIGGS) ) {
          cat.higgs = Particle(ptcl); ++Nhiggs;
        }
        // c) if HepMC::signal_proces_vertex is missing
        //    set hard-scatter vertex based on first Higgs boson
        if ( HSvtx==nullptr && ptcl->production_vertex() && !hasParent(ptcl,PID::HIGGS) )
          HSvtx = ptcl->production_vertex();
      }
 
      // Make sure things are in order so far
      if (Nhiggs!=1)
        return error(cat,HTXS::HIGGS_IDENTIFICATION,
                     "Current event has "+std::to_string(Nhiggs)+" Higgs bosons. There must be only one.");
      if (cat.higgs.children().size()<2)
        return error(cat,HTXS::HIGGS_DECAY_IDENTIFICATION,
                     "Could not identify Higgs boson decay products.");
 
      if (HSvtx == nullptr)
        return error(cat,HTXS::HS_VTX_IDENTIFICATION,"Cannot find hard-scatter vertex of current event.");
 
      /*****
       * Step 2.
       *   Identify associated vector bosons
       */
 
      // Find associated vector bosons
      bool is_uncatdV = false;
      Particles uncatV_decays;
      FourMomentum uncatV_p4(0,0,0,0);
      FourVector uncatV_v4(0,0,0,0);
      int nWs=0, nZs=0;
      if ( isVH(prodMode) ) {
        for (auto ptcl:Rivet::HepMCUtils::particles(HSvtx,Relatives::CHILDREN)) {
          if (PID::isW(ptcl->pdg_id())) { ++nWs; cat.V=Particle(ptcl); }
          if (PID::isZ(ptcl->pdg_id())) { ++nZs; cat.V=Particle(std::move(ptcl)); }
        }
        if(nWs+nZs>0) cat.V = getLastInstance(cat.V);
        else {
          for (auto ptcl:Rivet::HepMCUtils::particles(HSvtx,Relatives::CHILDREN)) {
            if (!PID::isHiggs(ptcl->pdg_id())) {
              uncatV_decays += Particle(ptcl);
              uncatV_p4 += Particle(ptcl).momentum();
              uncatV_v4 += Particle(std::move(ptcl)).origin();
            }
          }
          is_uncatdV = true; cat.V = Particle(24,uncatV_p4,uncatV_v4);
        }
      }
 
      if ( !is_uncatdV ){
 
        if ( isVH(prodMode) && !cat.V.genParticle()->end_vertex() )
          return error(cat,HTXS::VH_DECAY_IDENTIFICATION,"Vector boson does not decay!");
 
        if ( isVH(prodMode) && cat.V.children().size()<2 )
          return error(cat,HTXS::VH_DECAY_IDENTIFICATION,"Vector boson does not decay!");
 
        if ( ( prodMode==HTXS::WH && (nZs>0||nWs!=1) ) ||
             ( (prodMode==HTXS::QQ2ZH||prodMode==HTXS::GG2ZH) && (nZs!=1||nWs>0) ) )
          return error(cat,HTXS::VH_IDENTIFICATION,"Found "+std::to_string(nWs)+" W-bosons and "+
                       std::to_string(nZs)+" Z-bosons. Inconsitent with VH expectation.");
      }
 
      // Find and store the W-bosons from ttH->WbWbH
      Particles Ws;
      if ( prodMode==HTXS::TTH || prodMode==HTXS::TH ){
        // loop over particles produced in hard-scatter vertex
              for ( auto ptcl : Rivet::HepMCUtils::particles(std::move(HSvtx),Relatives::CHILDREN) ) {
                if ( !PID::isTop(ptcl->pdg_id()) ) continue;
          Particle top = getLastInstance(Particle(std::move(ptcl)));
          if ( top.genParticle()->end_vertex() )
            for (const auto &child:top.children())
              if ( PID::isW(child.pid()) ) Ws += getLastInstance(child);
        }
      }
 
      // Make sure result make sense
      if ( (prodMode==HTXS::TTH && Ws.size()<2) || (prodMode==HTXS::TH && Ws.size()<1 ) )
        return error(cat,HTXS::TOP_W_IDENTIFICATION,"Failed to identify W-boson(s) from t-decay!");
 
      /*****
       * Step 3.
       *   Build jets
       *   Make sure all stable particles are present
       */
 
      // Create a list of the vector bosons that decay leptonically
      // Either the vector boson produced in association with the Higgs boson,
      // or the ones produced from decays of top quarks produced with the Higgs
      Particles leptonicVs;
      if ( !is_uncatdV ){
        if ( isVH(prodMode) && !quarkDecay(cat.V) ) leptonicVs += cat.V;
      }else leptonicVs = std::move(uncatV_decays);
      for ( const auto & W:Ws ) if ( W.genParticle()->end_vertex() && !quarkDecay(W) ) leptonicVs += W;
 
      // Obtain all stable, final-state particles
      const Particles FS = apply<FinalState>(event, "FS").particles();
      Particles hadrons;
      FourMomentum sum(0,0,0,0), vSum(0,0,0,0), hSum(0,0,0,0);
      for ( const Particle &p : FS ) {
        // Add up the four momenta of all stable particles as a cross check
        sum += p.momentum();
        // ignore particles from the Higgs boson
        if ( originateFrom(p,cat.higgs) ) { hSum += p.momentum(); continue; }
        // Cross-check the V decay products for VH
        if ( isVH(prodMode) && !is_uncatdV && originateFrom(p,Ws) ) vSum += p.momentum();
        // ignore final state particles from leptonic V decays
        if ( leptonicVs.size() && originateFrom(p,leptonicVs) ) continue;
        // All particles reaching here are considered hadrons and will be used to build jets
        hadrons += p;
      }
 
      cat.p4decay_higgs = hSum;
      cat.p4decay_V = vSum;
 
      FinalState fps_temp;
      FastJets jets(fps_temp,
#if RIVET_VERSION_CODE >= 40000
                    JetAlg::ANTIKT,
#else
                    FastJets::ANTIKT,
#endif // RIVET_VERSION_CODE
                    0.4 );
      jets.calc(hadrons);
 
      cat.jets25 = jets.jetsByPt( Cuts::pT > 25.0 );
      cat.jets30 = jets.jetsByPt( Cuts::pT > 30.0 );
 
      // check that four mometum sum of all stable particles satisfies momentum consevation
      if ( sum.pt()>0.1 )
        return error(cat,HTXS::MOMENTUM_CONSERVATION,"Four vector sum does not amount to pT=0, m=E=sqrt(s), but pT="+
                     std::to_string(sum.pt())+" GeV and m = "+std::to_string(sum.mass())+" GeV");
 
      // check if V-boson was not included in the event record but decay particles were
      // EFT contact interaction: return UNKNOWN for category but set all event/particle kinematics
      if(is_uncatdV)
        return error(cat,HTXS::VH_IDENTIFICATION,"Failed to identify associated V-boson!");
 
      /*****
       * Step 4.
       *   Classify and save output
       */
 
      // Apply the categorization categorization
      cat.isZ2vvDecay = false;
      if( (prodMode==HTXS::GG2ZH || prodMode==HTXS::QQ2ZH) && !quarkDecay(cat.V) && !ChLeptonDecay(cat.V) ) cat.isZ2vvDecay = true;
      cat.stage0_cat = getStage0Category(prodMode,cat.higgs,cat.V);
      cat.stage1_cat_pTjet25GeV = getStage1Category(prodMode,cat.higgs,cat.jets25,cat.V);
      cat.stage1_cat_pTjet30GeV = getStage1Category(prodMode,cat.higgs,cat.jets30,cat.V);
      cat.stage1_2_cat_pTjet25GeV = getStage1_2_Category(prodMode,cat.higgs,cat.jets25,cat.V);
      cat.stage1_2_cat_pTjet30GeV = getStage1_2_Category(prodMode,cat.higgs,cat.jets30,cat.V);
      cat.stage1_2_fine_cat_pTjet25GeV = getStage1_2_Fine_Category(prodMode,cat.higgs,cat.jets25,cat.V);
      cat.stage1_2_fine_cat_pTjet30GeV = getStage1_2_Fine_Category(prodMode,cat.higgs,cat.jets30,cat.V);
      cat.errorCode = HTXS::SUCCESS; ++m_errorCount[HTXS::SUCCESS];
 
      return cat;
    }


int getBin(double x, const std::vector<double>& bins) const {
    if (bins.empty() || x < bins.front()) {
        throw std::invalid_argument("Input value is out of bin range or bins vector is empty.");
    }
 
    for (size_t i = 1; i < bins.size(); ++i) {
        if (x < bins[i]) {
            return static_cast<int>(i - 1);
        }
    }
 
    return static_cast<int>(bins.size() - 1);
}

    int vbfTopology(const Jets &jets, const Particle &higgs) const {
      if (jets.size()<2) return 0;
      const FourMomentum &j1=jets[0].momentum(), &j2=jets[1].momentum();
      bool VBFtopo = (j1+j2).mass() > 400.0 && std::abs(j1.rapidity()-j2.rapidity()) > 2.8;
      return VBFtopo ? (j1+j2+higgs.momentum()).pt()<25 ? 2 : 1 : 0;
    }

    int vbfTopology_Stage1_2(const Jets &jets, const Particle &higgs) const {
      if (jets.size()<2) return 0;
      const FourMomentum &j1=jets[0].momentum(), &j2=jets[1].momentum();
      double mjj = (j1+j2).mass();
      if(mjj>350 && mjj<=700) return (j1+j2+higgs.momentum()).pt()<25 ? 1 : 2;
      else if(mjj>700) return (j1+j2+higgs.momentum()).pt()<25 ? 3 : 4;
      else return 0;
    }

    int vbfTopology_Stage1_2_Fine(const Jets &jets, const Particle &higgs) const {
      if (jets.size()<2) return 0;
      const FourMomentum &j1=jets[0].momentum(), &j2=jets[1].momentum();
      double mjj = (j1+j2).mass();
      if(mjj>350 && mjj<=700) return (j1+j2+higgs.momentum()).pt()<25 ? 1 : 2;
      else if(mjj>700 && mjj<=1000) return (j1+j2+higgs.momentum()).pt()<25 ? 3 : 4;
      else if(mjj>1000 && mjj<=1500) return (j1+j2+higgs.momentum()).pt()<25 ? 5 : 6;
      else if(mjj>1500) return (j1+j2+higgs.momentum()).pt()<25 ? 7 : 8;
      else return 0;
    }

    bool isVH(HTXS::HiggsProdMode p) const { return p==HTXS::WH || p==HTXS::QQ2ZH || p==HTXS::GG2ZH; }

    HTXS::Stage0::Category getStage0Category(const HTXS::HiggsProdMode prodMode,
                                             const Particle &higgs,
                                             const Particle &V) const {
      using namespace HTXS::Stage0;
      int ctrlHiggs = std::abs(higgs.rapidity())<2.5;
      // Special cases first, qq→Hqq
      if ( (prodMode==HTXS::WH||prodMode==HTXS::QQ2ZH) && quarkDecay(V) ) {
        return ctrlHiggs ? VH2HQQ : VH2HQQ_FWDH;
      } else if ( prodMode==HTXS::GG2ZH && quarkDecay(V) ) {
        return Category(HTXS::GGF*10 + ctrlHiggs);
      }
      // General case after
      return  Category(prodMode*10 + ctrlHiggs);
    }

    HTXS::Stage1::Category getStage1Category(const HTXS::HiggsProdMode prodMode,
                                             const Particle &higgs,
                                             const Jets &jets,
                                             const Particle &V) const {
      using namespace HTXS::Stage1;
      int Njets=jets.size(), ctrlHiggs = std::abs(higgs.rapidity())<2.5, fwdHiggs = !ctrlHiggs;
      double pTj1 = jets.size() ? jets[0].momentum().pt() : 0;
      int vbfTopo = vbfTopology(jets,higgs);
 
      // 1. GGF Stage 1 categories
      //    Following YR4 write-up: XXXXX
      if (prodMode==HTXS::GGF || (prodMode==HTXS::GG2ZH && quarkDecay(V)) ) {
        if (fwdHiggs)        return GG2H_FWDH;
        if (Njets==0)        return GG2H_0J;
        else if (Njets==1)   return Category(GG2H_1J_PTH_0_60+getBin(higgs.pt(),{0,60,120,200}));
        else if (Njets>=2) {
          // events with pT_H>200 get priority over VBF cuts
          if(higgs.pt()<=200){
            if      (vbfTopo==2) return GG2H_VBFTOPO_JET3VETO;
            else if (vbfTopo==1) return GG2H_VBFTOPO_JET3;
          }
          // Njets >= 2jets without VBF topology
          return Category(GG2H_GE2J_PTH_0_60+getBin(higgs.pt(),{0,60,120,200}));
        }
      }
      // 2. Electroweak qq->Hqq Stage 1 categories
      else if (prodMode==HTXS::VBF || ( isVH(prodMode) && quarkDecay(V)) ) {
        if (std::abs(higgs.rapidity())>2.5) return QQ2HQQ_FWDH;
              if (pTj1>200) return QQ2HQQ_PTJET1_GT200;
        if (vbfTopo==2) return QQ2HQQ_VBFTOPO_JET3VETO;
        if (vbfTopo==1) return QQ2HQQ_VBFTOPO_JET3;
        double mjj = jets.size()>1 ? (jets[0].mom()+jets[1].mom()).mass():0;
        if ( 60 < mjj && mjj < 120 ) return QQ2HQQ_VH2JET;
              return QQ2HQQ_REST;
      }
      // 3. WH->Hlv categories
      else if (prodMode==HTXS::WH) {
        if (fwdHiggs) return QQ2HLNU_FWDH;
        else if (V.pt()<150) return QQ2HLNU_PTV_0_150;
              else if (V.pt()>250) return QQ2HLNU_PTV_GT250;
              // 150 < pTV/GeV < 250
              return jets.size()==0 ? QQ2HLNU_PTV_150_250_0J : QQ2HLNU_PTV_150_250_GE1J;
      }
      // 4. qq->ZH->llH categories
      else if (prodMode==HTXS::QQ2ZH) {
        if (fwdHiggs) return QQ2HLL_FWDH;
              else if (V.pt()<150) return QQ2HLL_PTV_0_150;
              else if (V.pt()>250) return QQ2HLL_PTV_GT250;
              // 150 < pTV/GeV < 250
              return jets.size()==0 ? QQ2HLL_PTV_150_250_0J : QQ2HLL_PTV_150_250_GE1J;
      }
      // 5. gg->ZH->llH categories
      else if (prodMode==HTXS::GG2ZH ) {
        if (fwdHiggs) return GG2HLL_FWDH;
        if      (V.pt()<150) return GG2HLL_PTV_0_150;
        else if (jets.size()==0) return GG2HLL_PTV_GT150_0J;
        return GG2HLL_PTV_GT150_GE1J;
      }
      // 6.ttH,bbH,tH categories
      else if (prodMode==HTXS::TTH) return Category(TTH_FWDH+ctrlHiggs);
      else if (prodMode==HTXS::BBH) return Category(BBH_FWDH+ctrlHiggs);
      else if (prodMode==HTXS::TH ) return Category(TH_FWDH+ctrlHiggs);
      return UNKNOWN;
    }

    HTXS::Stage1_2::Category getStage1_2_Category(const HTXS::HiggsProdMode prodMode,
                         const Particle &higgs,
                         const Jets &jets,
                         const Particle &V) const {
      using namespace HTXS::Stage1_2;
      int Njets=jets.size(), ctrlHiggs = std::abs(higgs.rapidity())<2.5, fwdHiggs = !ctrlHiggs;
      int vbfTopo = vbfTopology_Stage1_2(jets,higgs);
 
      // 1. GGF Stage 1 categories
      //    Following YR4 write-up: XXXXX
      if (prodMode==HTXS::GGF || (prodMode==HTXS::GG2ZH && quarkDecay(V)) ) {
    if (fwdHiggs)        return GG2H_FWDH;
    if ( higgs.pt()>200 ) return Category(GG2H_PTH_200_300+getBin(higgs.pt(),{200,300,450,650}));
    if (Njets==0)  return higgs.pt()<10 ? GG2H_0J_PTH_0_10 : GG2H_0J_PTH_GT10;
    if (Njets==1)  return Category(GG2H_1J_PTH_0_60+getBin(higgs.pt(),{0,60,120,200}));
    if (Njets>1){
        //VBF topology
        if(vbfTopo) return Category(GG2H_GE2J_MJJ_350_700_PTH_0_200_PTHJJ_0_25+vbfTopo-1);
        //Njets >= 2jets without VBF topology (mjj<350)
        return Category(GG2H_GE2J_MJJ_0_350_PTH_0_60+getBin(higgs.pt(),{0,60,120,200}));
    }
      }
 
      // 2. Electroweak qq->Hqq Stage 1.2 categories
      else if (prodMode==HTXS::VBF || ( isVH(prodMode) && quarkDecay(V)) ) {
    if (std::abs(higgs.rapidity())>2.5) return QQ2HQQ_FWDH;
    int Njets=jets.size();
    if (Njets==0)        return QQ2HQQ_0J;
    else if (Njets==1)   return QQ2HQQ_1J;
    else if (Njets>=2) {
        double mjj = (jets[0].mom()+jets[1].mom()).mass();
        if ( mjj < 60 )      return QQ2HQQ_GE2J_MJJ_0_60;
        else if ( 60 < mjj && mjj < 120 ) return QQ2HQQ_GE2J_MJJ_60_120;
        else if ( 120 < mjj && mjj < 350 ) return QQ2HQQ_GE2J_MJJ_120_350;
        else if (  mjj > 350 ) {
            if (higgs.pt()>200) return QQ2HQQ_GE2J_MJJ_GT350_PTH_GT200;
            if(vbfTopo) return Category(QQ2HQQ_GE2J_MJJ_GT350_PTH_GT200+vbfTopo);
        }
    }
      }
      // 3. WH->Hlv categories
      else if (prodMode==HTXS::WH) {
        if (fwdHiggs) return QQ2HLNU_FWDH;
        else if (V.pt()<75) return QQ2HLNU_PTV_0_75;
        else if (V.pt()<150) return QQ2HLNU_PTV_75_150;
        else if (V.pt()>250) return QQ2HLNU_PTV_GT250;
        // 150 < pTV/GeV < 250
        return jets.size()==0 ? QQ2HLNU_PTV_150_250_0J : QQ2HLNU_PTV_150_250_GE1J;
      }
      // 4. qq->ZH->llH categories
      else if (prodMode==HTXS::QQ2ZH) {
        if (fwdHiggs) return QQ2HLL_FWDH;
        else if (V.pt()<75) return QQ2HLL_PTV_0_75;
        else if (V.pt()<150) return QQ2HLL_PTV_75_150;
        else if (V.pt()>250) return QQ2HLL_PTV_GT250;
        // 150 < pTV/GeV < 250
        return jets.size()==0 ? QQ2HLL_PTV_150_250_0J : QQ2HLL_PTV_150_250_GE1J;
      }
      // 5. gg->ZH->llH categories
      else if (prodMode==HTXS::GG2ZH ) {
        if (fwdHiggs) return GG2HLL_FWDH;
        else if (V.pt()<75) return GG2HLL_PTV_0_75;
        else if (V.pt()<150) return GG2HLL_PTV_75_150;
        else if (V.pt()>250) return GG2HLL_PTV_GT250;
        return jets.size()==0 ? GG2HLL_PTV_150_250_0J : GG2HLL_PTV_150_250_GE1J;
      }
      // 6.ttH,bbH,tH categories
      else if (prodMode==HTXS::TTH) {
        if (fwdHiggs) return TTH_FWDH;
        else return Category(TTH_PTH_0_60+getBin(higgs.pt(),{0,60,120,200,300}));
      }
      else if (prodMode==HTXS::BBH) return Category(BBH_FWDH+ctrlHiggs);
      else if (prodMode==HTXS::TH ) return Category(TH_FWDH+ctrlHiggs);
      return UNKNOWN;
    }

    HTXS::Stage1_2_Fine::Category getStage1_2_Fine_Category(const HTXS::HiggsProdMode prodMode,
                         const Particle &higgs,
                         const Jets &jets,
                         const Particle &V) const {
      using namespace HTXS::Stage1_2_Fine;
      int Njets=jets.size(), ctrlHiggs = std::abs(higgs.rapidity())<2.5, fwdHiggs = !ctrlHiggs;
      int vbfTopo = vbfTopology_Stage1_2_Fine(jets,higgs);
 
      // 1. GGF Stage 1.2 categories
      //    Following YR4 write-up: XXXXX
      if (prodMode==HTXS::GGF || (prodMode==HTXS::GG2ZH && quarkDecay(V)) ) {
    if (fwdHiggs)        return GG2H_FWDH;
    if ( higgs.pt()>200 ){
      if (Njets>0){
        double pTHj = (jets[0].momentum()+higgs.momentum()).pt();
        if( pTHj/higgs.pt()>0.15 ) return Category(GG2H_PTH_200_300_PTHJoverPTH_GT15+getBin(higgs.pt(),{200,300,450,650}));
        else return Category(GG2H_PTH_200_300_PTHJoverPTH_0_15+getBin(higgs.pt(),{200,300,450,650}));
      }
      else return Category(GG2H_PTH_200_300_PTHJoverPTH_0_15+getBin(higgs.pt(),{200,300,450,650}));
    }
    if (Njets==0)  return higgs.pt()<10 ? GG2H_0J_PTH_0_10 : GG2H_0J_PTH_GT10;
    if (Njets==1)  return Category(GG2H_1J_PTH_0_60+getBin(higgs.pt(),{0,60,120,200}));
    if (Njets>1){
        //double mjj = (jets[0].mom()+jets[1].mom()).mass();
        double pTHjj = (jets[0].momentum()+jets[1].momentum()+higgs.momentum()).pt();
        //VBF topology
        if(vbfTopo) return Category(GG2H_GE2J_MJJ_350_700_PTH_0_200_PTHJJ_0_25+vbfTopo-1);
        //Njets >= 2jets without VBF topology (mjj<350)
        if (pTHjj<25) return Category(GG2H_GE2J_MJJ_0_350_PTH_0_60_PTHJJ_0_25+getBin(higgs.pt(),{0,60,120,200}));
        else return Category(GG2H_GE2J_MJJ_0_350_PTH_0_60_PTHJJ_GT25+getBin(higgs.pt(),{0,60,120,200}));
    }
      }
 
      // 2. Electroweak qq->Hqq Stage 1.2 categories
      else if (prodMode==HTXS::VBF || ( isVH(prodMode) && quarkDecay(V)) ) {
    if (std::abs(higgs.rapidity())>2.5) return QQ2HQQ_FWDH;
    int Njets=jets.size();
    if (Njets==0)        return QQ2HQQ_0J;
    else if (Njets==1)   return QQ2HQQ_1J;
    else if (Njets>=2) {
        double mjj = (jets[0].mom()+jets[1].mom()).mass();
        double pTHjj = (jets[0].momentum()+jets[1].momentum()+higgs.momentum()).pt();
        if (mjj<350){
            if (pTHjj<25) return Category(QQ2HQQ_GE2J_MJJ_0_60_PTHJJ_0_25+getBin(mjj,{0,60,120,350}));
            else return Category(QQ2HQQ_GE2J_MJJ_0_60_PTHJJ_GT25+getBin(mjj,{0,60,120,350}));
        } else { //mjj>350 GeV
            if (higgs.pt()<200){
                return Category(QQ2HQQ_GE2J_MJJ_350_700_PTH_0_200_PTHJJ_0_25+vbfTopo-1);
            } else {
                return Category(QQ2HQQ_GE2J_MJJ_350_700_PTH_GT200_PTHJJ_0_25+vbfTopo-1);
            }
        }
    }
      }
      // 3. WH->Hlv categories
      else if (prodMode==HTXS::WH) {
        if (fwdHiggs) return QQ2HLNU_FWDH;
        int Njets=jets.size();
        if (Njets==0) return Category(QQ2HLNU_PTV_0_75_0J+getBin(V.pt(),{0,75,150,250,400}));
        if (Njets==1) return Category(QQ2HLNU_PTV_0_75_1J+getBin(V.pt(),{0,75,150,250,400}));
        return Category(QQ2HLNU_PTV_0_75_GE2J+getBin(V.pt(),{0,75,150,250,400}));
      }
      // 4. qq->ZH->llH categories
      else if (prodMode==HTXS::QQ2ZH) {
        if (fwdHiggs) return QQ2HLL_FWDH;
        int Njets=jets.size();
        if (Njets==0) return Category(QQ2HLL_PTV_0_75_0J+getBin(V.pt(),{0,75,150,250,400}));
        if (Njets==1) return Category(QQ2HLL_PTV_0_75_1J+getBin(V.pt(),{0,75,150,250,400}));
        return Category(QQ2HLL_PTV_0_75_GE2J+getBin(V.pt(),{0,75,150,250,400}));
      }
      // 5. gg->ZH->llH categories
      else if (prodMode==HTXS::GG2ZH ) {
        if (fwdHiggs) return GG2HLL_FWDH;
        int Njets=jets.size();
        if (Njets==0) return Category(GG2HLL_PTV_0_75_0J+getBin(V.pt(),{0,75,150,250,400}));
        if (Njets==1) return Category(GG2HLL_PTV_0_75_1J+getBin(V.pt(),{0,75,150,250,400}));
        return Category(GG2HLL_PTV_0_75_GE2J+getBin(V.pt(),{0,75,150,250,400}));
      }
      // 6.ttH,bbH,tH categories
      else if (prodMode==HTXS::TTH) {
        if (fwdHiggs) return TTH_FWDH;
        else return Category(TTH_PTH_0_60+getBin(higgs.pt(),{0,60,120,200,300,450}));
      }
      else if (prodMode==HTXS::BBH) return Category(BBH_FWDH+ctrlHiggs);
      else if (prodMode==HTXS::TH ) return Category(TH_FWDH+ctrlHiggs);
      return UNKNOWN;
    }

 


    void setHiggsProdMode( HTXS::HiggsProdMode prodMode ){ m_HiggsProdMode = prodMode; }

    void init() {
      printf("==============================================================\n");
      printf("========     HiggsTemplateCrossSections Initialization     =========\n");
      printf("==============================================================\n");
      // check that the production mode has been set
      // if running in standalone Rivet the production mode is set through an env variable
      if (m_HiggsProdMode==HTXS::UNKNOWN) {
        char *pm_env = getenv("HIGGSPRODMODE");
        string pm(pm_env==nullptr?"":pm_env);
        if      ( pm == "GGF"   ) m_HiggsProdMode = HTXS::GGF;
        else if ( pm == "VBF"   ) m_HiggsProdMode = HTXS::VBF;
        else if ( pm == "WH"    ) m_HiggsProdMode = HTXS::WH;
        else if ( pm == "ZH"    ) m_HiggsProdMode = HTXS::QQ2ZH;
        else if ( pm == "QQ2ZH" ) m_HiggsProdMode = HTXS::QQ2ZH;
        else if ( pm == "GG2ZH" ) m_HiggsProdMode = HTXS::GG2ZH;
        else if ( pm == "TTH"   ) m_HiggsProdMode = HTXS::TTH;
        else if ( pm == "BBH"   ) m_HiggsProdMode = HTXS::BBH;
        else if ( pm == "TH"    ) m_HiggsProdMode = HTXS::TH;
        else {
          MSG_WARNING("No HIGGSPRODMODE shell variable found. Needed when running Rivet stand-alone.");
        }
      }
 
      // Projections for final state particles
      const FinalState FS;
      declare(FS,"FS");
 
      // initialize the histograms with for each of the stages
      initializeHistos();
      m_sumw = 0.0;
      printf("==============================================================\n");
      printf("========             Higgs prod mode %d              =========\n",m_HiggsProdMode);
      printf("========          Sucessful Initialization           =========\n");
      printf("==============================================================\n");
    }
 
    // Perform the per-event analysis
    void analyze(const Event& event) {
 
      // get the classification
      HiggsClassification cat = classifyEvent(event,m_HiggsProdMode);
 
      // Fill histograms: categorization --> linerize the categories
      const double weight = 1.; // Event weights are now all 1 in Rivet
      m_sumw += weight;
 
      int F=cat.stage0_cat%10, P=cat.stage1_cat_pTjet30GeV/100;
      m_hist_stage0->fill( cat.stage0_cat/10*2+F, weight );
 
      // Stage 1 enum offsets for each production mode: GGF=12, VBF=6, WH= 5, QQ2ZH=5, GG2ZH=4, TTH=2, BBH=2, TH=2
      static const vector<int> offset({0,1,13,19,24,29,33,35,37,39});
      int off = offset[P];
      // Stage 1.2 enum offsets for each production mode: GGF=17, VBF=11, WH= 6, QQ2ZH=6, GG2ZH=6, TTH=6, BBH=2, TH=2
      static const vector<int> offset1_2({0,1,18,29,35,41,47,53,55,57});
      int off1_2 = offset1_2[P];
      // Stage 1.2-Fine enum offsets for each production mode: GGF=28, VBF=25, WH= 16, QQ2ZH=16, GG2ZH=16, TTH=7, BBH=2, TH=2
      static const vector<int> offset1_2_Fine({0,1,29,54,70,86,102,109,111,113});
      int off1_2_Fine = offset1_2_Fine[P];
 
      m_hist_stage1_pTjet25->fill(cat.stage1_cat_pTjet25GeV%100 + off, weight);
      m_hist_stage1_pTjet30->fill(cat.stage1_cat_pTjet30GeV%100 + off, weight);
      m_hist_stage1_2_pTjet25->fill(cat.stage1_2_cat_pTjet25GeV%100 + off1_2, weight);
      m_hist_stage1_2_pTjet30->fill(cat.stage1_2_cat_pTjet30GeV%100 + off1_2, weight);
      m_hist_stage1_2_fine_pTjet25->fill(cat.stage1_2_fine_cat_pTjet25GeV%100 + off1_2_Fine, weight);
      m_hist_stage1_2_fine_pTjet30->fill(cat.stage1_2_fine_cat_pTjet30GeV%100 + off1_2_Fine, weight);
 
      // Fill histograms: variables used in the categorization
      m_hist_pT_Higgs->fill(cat.higgs.pT(),weight);
      m_hist_y_Higgs->fill(cat.higgs.rapidity(),weight);
      m_hist_pT_V->fill(cat.V.pT(),weight);
 
      m_hist_Njets25->fill(cat.jets25.size(),weight);
      m_hist_Njets30->fill(cat.jets30.size(),weight);
 
      m_hist_isZ2vv->fill(cat.isZ2vvDecay, weight);
 
      // Jet variables. Use jet collection with pT threshold at 30 GeV
      if (cat.jets30.size()) m_hist_pT_jet1->fill(cat.jets30[0].pt(),weight);
      if (cat.jets30.size()>=2) {
        const FourMomentum &j1 = cat.jets30[0].momentum(), &j2 = cat.jets30[1].momentum();
        m_hist_deltay_jj->fill(std::abs(j1.rapidity()-j2.rapidity()),weight);
        m_hist_dijet_mass->fill((j1+j2).mass(),weight);
        m_hist_pT_Hjj->fill((j1+j2+cat.higgs.momentum()).pt(),weight);
      }
    }
 
    void printClassificationSummary(){
      MSG_INFO (" ====================================================== ");
      MSG_INFO ("      Higgs Template X-Sec Categorization Tool          ");
      MSG_INFO ("                Status Code Summary                     ");
      MSG_INFO (" ====================================================== ");
      bool allSuccess = (numEvents()==m_errorCount[HTXS::SUCCESS]);
      if ( allSuccess ) MSG_INFO ("     >>>> All "<< m_errorCount[HTXS::SUCCESS] <<" events successfully categorized!");
      else{
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::SUCCESS] <<" events successfully categorized");
        MSG_INFO ("     >>>> --> the following errors occured:");
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::PRODMODE_DEFINED] <<" had an undefined Higgs production mode.");
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::MOMENTUM_CONSERVATION] <<" failed momentum conservation.");
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::HIGGS_IDENTIFICATION] <<" failed to identify a valid Higgs boson.");
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::HS_VTX_IDENTIFICATION] <<" failed to identify the hard scatter vertex.");
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::VH_IDENTIFICATION] <<" VH: to identify a valid V-boson.");
        MSG_INFO ("     >>>> "<< m_errorCount[HTXS::TOP_W_IDENTIFICATION] <<" failed to identify valid Ws from top decay.");
      }
      MSG_INFO (" ====================================================== ");
      MSG_INFO (" ====================================================== ");
    }
 
 
    void finalize() {
      printClassificationSummary();
      double sf = m_sumw>0?1.0/m_sumw:1.0;
      for (auto hist:{m_hist_stage0,m_hist_stage1_pTjet25,m_hist_stage1_pTjet30,m_hist_stage1_2_pTjet25,m_hist_stage1_2_pTjet30,m_hist_stage1_2_fine_pTjet25,m_hist_stage1_2_fine_pTjet30,
        m_hist_Njets25,m_hist_Njets30,m_hist_pT_Higgs,m_hist_y_Higgs,m_hist_pT_V,m_hist_pT_jet1,m_hist_deltay_jj,m_hist_dijet_mass,m_hist_pT_Hjj,m_hist_isZ2vv})
        scale(hist, sf);
    }
 
    /*
     *  initialize histograms
     */
 
    void initializeHistos(){
      book(m_hist_stage0,"HTXS_stage0",20,0,20);
      book(m_hist_stage1_pTjet25,"HTXS_stage1_pTjet25",40,0,40);
      book(m_hist_stage1_pTjet30,"HTXS_stage1_pTjet30",40,0,40);
      book(m_hist_stage1_2_pTjet25,"HTXS_stage1_2_pTjet25",57,0,57);
      book(m_hist_stage1_2_pTjet30,"HTXS_stage1_2_pTjet30",57,0,57);
      book(m_hist_stage1_2_fine_pTjet25,"HTXS_stage1_2_fine_pTjet25",113,0,113);
      book(m_hist_stage1_2_fine_pTjet30,"HTXS_stage1_2_fine_pTjet30",113,0,113);
      book(m_hist_pT_Higgs,"pT_Higgs",80,0,400);
      book(m_hist_y_Higgs,"y_Higgs",80,-4,4);
      book(m_hist_pT_V,"pT_V",80,0,400);
      book(m_hist_pT_jet1,"pT_jet1",80,0,400);
      book(m_hist_deltay_jj ,"deltay_jj",50,0,10);
      book(m_hist_dijet_mass,"m_jj",50,0,2000);
      book(m_hist_pT_Hjj,"pT_Hjj",50,0,250);
      book(m_hist_Njets25,"Njets25",10,0,10);
      book(m_hist_Njets30,"Njets30",10,0,10);
      book(m_hist_isZ2vv,"isZ2vv",2,0,2);
    }

 
    /*
     *    initialize private members used in the classification procedure
     */
 
  private:
    double m_sumw=0.0;
    HTXS::HiggsProdMode m_HiggsProdMode;
    mutable std::array<std::atomic<size_t>, HTXS::NUM_ERRORCODES> m_errorCount ATLAS_THREAD_SAFE {};
    Histo1DPtr m_hist_stage0;
    Histo1DPtr m_hist_stage1_pTjet25, m_hist_stage1_pTjet30;
    Histo1DPtr m_hist_stage1_2_pTjet25, m_hist_stage1_2_pTjet30;
    Histo1DPtr m_hist_stage1_2_fine_pTjet25, m_hist_stage1_2_fine_pTjet30;
    Histo1DPtr m_hist_pT_Higgs, m_hist_y_Higgs;
    Histo1DPtr m_hist_pT_V, m_hist_pT_jet1;
    Histo1DPtr m_hist_deltay_jj, m_hist_dijet_mass, m_hist_pT_Hjj;
    Histo1DPtr m_hist_Njets25, m_hist_Njets30;
    Histo1DPtr m_hist_isZ2vv;
  };
 
  // the PLUGIN only needs to be decleared when running standalone Rivet
  // and causes compilation / linking issues if included in Athena / RootCore
  //check for Rivet environment variable RIVET_ANALYSIS_PATH
#ifdef RIVET_ANALYSIS_PATH
  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(HiggsTemplateCrossSections);
#endif
 
}
 
#endif