Pythia8::DecayToSUEP Class Reference

Pythia8 UserHook to decay a given scalar particle to SUEP. More...

Inheritance diagram for Pythia8::DecayToSUEP:

Collaboration diagram for Pythia8::DecayToSUEP:

Public Member Functions
	DecayToSUEP ()
	~DecayToSUEP ()
virtual bool	canVetoProcessLevel ()
virtual bool	doVetoProcessLevel (Event &process)

Private Attributes
Pythia8_UserHooks::UserSetting< int >	m_pdgId
	PDG Id of particle to be decayed to SUEP.
Pythia8_UserHooks::UserSetting< double >	m_mass
	Mass of system decaying [GeV].
Pythia8_UserHooks::UserSetting< double >	m_darkMesonMass
	Dark-meson mass parameter [GeV].
Pythia8_UserHooks::UserSetting< double >	m_darkTemperature
	Temperature parameter [GeV].

Detailed Description

Pythia8 UserHook to decay a given scalar particle to SUEP.

Details on models available on arXiv:1612.00850. This is an adaption from the available public code at: https://gitlab.com/simonknapen/suep_generator by Simon Knapen.

Definition at line 37 of file DecayToSUEP.cxx.

Constructor & Destructor Documentation

DecayToSUEP()

Pythia8::DecayToSUEP::DecayToSUEP ( )

inline

Definition at line 41 of file DecayToSUEP.cxx.

                 : 
      m_pdgId("DecayToSUEP:PDGId", 25), 
      m_mass("DecayToSUEP:Mass", 125.0),
      m_darkMesonMass("DecayToSUEP:DarkMesonMass", 1.), 
      m_darkTemperature("DecayToSUEP:DarkTemperature", 1.) {
      
      std::cout<<"**********************************************************"<<std::endl;
      std::cout<<"*                                                        *"<<std::endl;
      std::cout<<"*             Enabled SUEP decay UserHook!               *"<<std::endl;
      std::cout<<"*                                                        *"<<std::endl;
      std::cout<<"**********************************************************"<<std::endl;
      
    }

~DecayToSUEP()

Pythia8::DecayToSUEP::~DecayToSUEP ( )

inline

Definition at line 55 of file DecayToSUEP.cxx.

{}

Member Function Documentation

canVetoProcessLevel()

virtual bool Pythia8::DecayToSUEP::canVetoProcessLevel ( )

inlinevirtual

Definition at line 58 of file DecayToSUEP.cxx.

                                       {
      return true;
    }

doVetoProcessLevel()

bool Pythia8::DecayToSUEP::doVetoProcessLevel ( Event & process )

virtual

Definition at line 92 of file DecayToSUEP.cxx.

  {
#ifdef SUEP_DEBUG
    std::cout << "[SUEP_DEBUG] " << "Start of user hook for this event." << std::endl;
#endif
 
    //First, find the particle to decay
    bool particleFound=false;
 
#ifdef SUEP_DEBUG
    for (int ii=0; ii < process.size(); ++ii) {
      std::cout << "[SUEP_DEBUG] " << ii << ": id=" << process[ii].id() << ", Final=" << process[ii].isFinal() << ", Status=" << process[ii].status() << ", daughter1=" << process[ii].daughter1() << ", daughter2=" << process[ii].daughter2() << std::endl;
    }
#endif
 
    for (int ii=0; ii < process.size(); ++ii) {
      if ( (process[ii].id() == m_pdgId(settingsPtr)) and (process[ii].daughter1()!=process[ii].daughter2() && process[ii].daughter1()>0 && process[ii].daughter2()>0) ) {
 
    Vec4 higgs4mom, mesonmom;
    vector< Vec4 > suep_shower4momenta; 
    particleFound=true;
 
    //setup SUEP shower
    static Suep_shower suep_shower(m_darkMesonMass(settingsPtr), m_darkTemperature(settingsPtr), m_mass(settingsPtr), rndmPtr);
 
#ifdef SUEP_DEBUG
    std::cout << "[SUEP_DEBUG] " << "Particle (pdgId=" << m_pdgId(settingsPtr) << ", isFinal=True) found. Decaying to SUEP now." << std::endl;
#endif
 
    // First undo decay
    process[ii].undoDecay();
 
    int originalEventSize = process.size();
 
    // Generate the shower, output are 4 vectors in the rest frame of the shower
    higgs4mom=process[ii].p();
    int nShowerAttempts=0;
    do {
      try {
        nShowerAttempts++;
        suep_shower4momenta=suep_shower.generate_shower();
        if( suep_shower4momenta.size()<3){
          //Failed to balance energy or less than 3 particles in the shower
          //Try again until nShowerAttempts >= 3
        } else {
          //All ok!
          nShowerAttempts = -1; //exit condition
        }
      } catch (std::exception &e) {
        //Failed to generate the shower!
        //Can happen in some rare circumstances, 
        //Try again until nShowerAttempts >= 3
      }
    } while ((nShowerAttempts > 0) && (nShowerAttempts < 3));
    if (nShowerAttempts >= 3) {
      //Something is seriously wrong then, print warning and skip to next event
      std::cout << "[SUEP] WARNING: Something went wrong in generating the shower. Skipping the event." << std::endl;
      return true; //veto the event!
    }
 
    // Loop over hidden sector mesons and append to the event   
    for (unsigned j = 0; j < suep_shower4momenta.size(); ++j){
      //construct pythia 4vector
      mesonmom = suep_shower4momenta[j];
            
      // boost to the lab frame
      mesonmom.bst(higgs4mom.px()/higgs4mom.e(),higgs4mom.py()/higgs4mom.e(), higgs4mom.pz()/higgs4mom.e());
            
      //append particle to the event. Hidden/dark meson pdg code is 999999.
      process.append(999999, 91, ii, 0, 0, 0, 0, 0, mesonmom.px(), mesonmom.py(), mesonmom.pz(), mesonmom.e(), m_darkMesonMass(settingsPtr)); 
 
#ifdef SUEP_DEBUG
      std::cout << "[SUEP_DEBUG] " << "Adding dark meson with px=" << mesonmom.px() << ", py=" << mesonmom.py() << ", pz=" << mesonmom.pz() << ", m=" << m_darkMesonMass(settingsPtr) << std::endl;
#endif
    }
 
    // Just to be sure, only modify Higgs status and daughters if a valid decay did happen
    if ( suep_shower4momenta.size() > 0 ) {
#ifdef SUEP_DEBUG
      std::cout << "[SUEP_DEBUG] " << "Setting original particle status-code as non-Final particle. Adding daughters with indices: " << originalEventSize << " - " << process.size()-1 << std::endl;
#endif
      // Change the status code of the Higgs to reflect that it has decayed.
      process[ii].statusNeg();
          
      //set daughters of the Higgs. Take advantage that we just appended them
      process[ii].daughters(originalEventSize, process.size()-1); 
    }
    
    //no need to continue the loop
    break;
 
      } // if particle to decay found
 
    } // loop over particles in the event
 
    if (not particleFound) {
      std::cout << "[DecayToSUEP] " << "Particle " << m_pdgId(settingsPtr) << " not found. Nothing to decay to SUEP for this event." << std::endl;
    } else {
#ifdef SUEP_DEBUG      
      std::cout << "[SEUP_DEBUG] " << "All Done for this event." << std::endl;
#endif
    }
#ifdef SUEP_DEBUG      
    std::cout << "[SUEP_DEBUG] Printing event after adding SUEP:" << std::endl;
    for (int ii=0; ii < process.size(); ++ii) {
      std::cout << "[SUEP_DEBUG] " << ii << ": id=" << process[ii].id() << ", Final=" << process[ii].isFinal() << ", mayDecay=" << process[ii].mayDecay() << ", Status=" << process[ii].status() << ", daughter1=" << process[ii].daughter1() << ", daughter2=" << process[ii].daughter2() << std::endl;
    }
#endif
 
    //return false: let the event continue
    return false;
  }

Member Data Documentation

m_darkMesonMass

Pythia8_UserHooks::UserSetting<double> Pythia8::DecayToSUEP::m_darkMesonMass

private

Dark-meson mass parameter [GeV].

Definition at line 81 of file DecayToSUEP.cxx.

m_darkTemperature

Pythia8_UserHooks::UserSetting<double> Pythia8::DecayToSUEP::m_darkTemperature

private

Temperature parameter [GeV].

Definition at line 84 of file DecayToSUEP.cxx.

m_mass

Pythia8_UserHooks::UserSetting<double> Pythia8::DecayToSUEP::m_mass

private

Mass of system decaying [GeV].

Definition at line 78 of file DecayToSUEP.cxx.

m_pdgId

Pythia8_UserHooks::UserSetting<int> Pythia8::DecayToSUEP::m_pdgId

private

PDG Id of particle to be decayed to SUEP.

Definition at line 75 of file DecayToSUEP.cxx.

---

The documentation for this class was generated from the following file:

• DecayToSUEP.cxx